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    External Conditions, Diseases, and Disorders

    External Conditions, Diseases, and Disorders

    By Arnold Plotnick, DVM

    The previous chapter gave you an idea how the body of the domestic cat is put together, the external parts as well as the complex internal systems and how they function. In the remaining chapters of this section, we take a look at some of most common and most serious conditions, diseases, and disorders affecting the different parts and systems of the cat. In this chapter, we discuss external conditions, injuries, diseases, and disorders of the skin and coat, ears and eyes, teeth, and paws and nails.

    Skin and Coat Injuries and Diseases

    Skin and Coat Injuries and Diseases

    The skin of cats is thinner than that of dogs and thus more prone to injury. Careless or rough handling, such as using improper grooming equipment or cat fights, can easily damage the skin, resulting in lacerations and punctures, which in turn can lead to infections and abscesses. Parasites, bacteria, and allergies can also lead to skins diseases as well as hair loss.


    Cat fights and their resultant injuries are a common reason for veterinary visits. Although cats living together indoors occasionally fight over territory or for owner attention, such scraps rarely lead to serious injury. Cats who encounter other cats outdoors, however, are more likely to fight, to fight more often, and to fight more seriously, usually over territory.

    Fights and overenthusiastic playing between cats are among the most common causes of injury to pet felines.

    Causes and symptoms

    Cats' teeth are sharp, and when they bite, they inflict puncture wounds. Cats have a tremendous amount of bacteria in their mouths, which are injected into the skin with a bite. Because puncture wounds in cats seal over quickly, this bacteria becomes trapped. The bone marrow sends out many white blood cells to help fight this infection. The white blood cells and bacteria accumulate to form a painful pocket of pus just beneath the skin. This collection of pus is an abscess. Abscesses are common in cats, owing to the tough, elastic nature of feline skin that so readily seals over contaminated puncture wounds and allows for pus to accumulate beneath it.

    Trauma and infection are not the only concern regarding cat bite injuries. Cat bites have the potential to transmit several life-threatening infectious diseases to other cats, such as the feline leukemia virus (FeLV), the feline immunodeficiency virus (FIV), and rabies.The majority of abscesses are seen in cats who go outdoors. Intact males are at higher risk than neutered males or females because they're more likely to roam and fight over territory. Typically, a cat who has been bitten appears fine after the encounter. Over the next two to four days, bacteria deposited in the wound begin to multiply, and as they do, the cat develops a fever, becomes lethargic, and often stops eating.

    Diagnosis and treatment

    Many cats are taken to the veterinarian at this stage, when the abscess appears as either a firm or soft painful swelling. In most cases, puncture wounds or small lacerations are present, and the area may feel warm. If not discovered in this early stage, the abscess will continue to swell, burrowing through tissues and accumulating more pus. The abscess may then burst through the overlying skin, releasing creamy yellow or brownish, foul-smelling pus. Overlying hair may become matted with dried discharge. Common locations for abscesses are the face and neck, tail, back, and legs, although any part of the body can be bitten during a fight. If a bite wound occurs in a location that does not have much loose overlying skin (a leg, for example), the infection can dissect its way through the tissues, causing a diffuse swelling instead of a discrete collection of pus. This diffuse swelling is called cellulitis.

    The earlier that treatment is instituted, the better the chances of the wound healing without complications. In most cases, the cat is anesthetized so that an incision can be made into the abscess. The wound is then flushed with an antibacterial solution to further remove pus and other debris. If the abscess is detected and addressed at an early stage, lancing and flushing (plus antibiotics) may be all that is required. If it's discovered at a later stage, when significant tissue damage has occurred beneath the skin, the veterinarian may need to debride the wound (that is, remove dead or compromised tissue). In some cases, the veterinarian may find it necessary to insert a drain (a piece of soft rubber tubing that exits the skin at the lowest point of the wound) to allow any future accumulation of fluid or pus to escape. After debriding, if the wound is large, sutures may be required to partially close it. Most wounds, however, are left open to drain and heal on their own. Very large skin defects may require some type of reconstructive skin surgery after the infection has resolved.

    The prognosis for a properly treated abscess is excellent. However, cats who engage in frequent fights are at high risk for contracting serious illnesses such as FeLV and FIV. Cats who contract these viruses may then spread them to other cats in future encounters. Cats with FeLV or FIV also have weakened defenses against infection and may have difficulty defeating an infection if bitten by other cats. Outdoor cats should be regularly tested for these viruses. Cats who go outdoors should also be current on their vaccinations, especially rabies and FeLV, and perhaps FIV. The best prevention is to keep all cats indoors and prevent them from roaming and fighting.

    Abscesses require veterinary care. This cat is having the abscess in her tail flushed and drained.


    A cyst is a hollow sac containing fluid or solid material. In cats, cysts appear as small bumps within the skin. They often feel like peas or marbles.

    Causes and symptoms

    One of the most common types of cyst that develop in cats is the sebaceous cyst, sometimes called an epidermal inclusion cyst or an epidermoid cyst. These cysts contain material secreted by the sebaceous glands. Sebaceous glands are located next to the hair follicles; they secrete sebum, an oily substance that protects and lubricates the skin. If a hair follicle becomes obstructed (blocked), sebum can accumulate abnormally and form a cyst.

    Diagnosis and treatment

    A diagnosis can be made by a technique called fine-needle aspiration. In this technique, the cyst is pierced with a needle, and the cyst material is aspirated into the hub of the needle and dispersed onto a microscope slide. Evaluation of the cystic material usually leads to proper diagnosis. In some instances, a skin biopsy may be necessary for definitive diagnosis. Sebaceous cysts are not painful (unless they become infected, which is uncommon) and are of no consequence. Treatment is rarely necessary. Other types of cysts that can be present in the skin include follicular cysts, dermoid cysts, and apocrine cysts. The vast majority of cysts are benign and have no clinical significance. Occasionally, however, a cyst may grow to a size large enough to bother the cat. In these cases, the cyst should be removed. Likewise, if the cyst material is infected, the material may need to be drained or the cyst may need to be surgically removed. Cats who cannot undergo surgery (due to ill health or financial concerns) can have the cyst drained rather than removed. Be aware, however, that although draining will reduce the size of the cyst, doing so is a temporary measure because the cyst will refill with material over time. Most cysts are discovered by the cat owner while petting the cat; sometimes the veterinarian finds them during a physical examination. If the veterinarian is unsure whether the skin lesion is a cyst, removal and biopsy may be recommended to make sure that it is not something dangerous, like cancer. If you find any kind of lump or bump on your cat, always bring it to the attention of your veterinarian.

    Allergic Dermatitis

    Skin allergies are a common finding in cats. When an allergic cat encounters an offending allergen, the immune system responds by sending inflammatory cells into the skin in an attempt to fend off the allergen. These inflammatory cells release substances that can cause the skin to become red, inflamed, and itchy. The most common types of allergic dermatitis in cats are food allergy, flea allergy, and atopy (allergy to inhaled substances). Clinical signs for each of these diseases often overlap, making diagnosis challenging.

    Food Allergy

    Allergy to food is a significant cause of itching and scratching in cats. Males and females are equally affected, and there is no particular age preference, although the majority of cats are young to middleaged (two to six years old). A sudden change in diet is not necessary for food allergy to develop, and, in fact, most cases of food allergy develop after a cat has been fed the same food for a long time.

    Causes and symptoms

    The most common offending substance in the food tends to be a protein source such as beef, lamb, or seafood. However, allergies can also develop to corn, soy, dairy components, and gluten. Food allergy can affect the gastrointestinal tract, causing vomiting and/or diarrhea, or it can affect the skin. In some cases, both systems are affected. When the skin is affected, the primary sign tends to be itching, which causes excessive licking, biting, scratching, and chewing at the skin. Hair loss is common because an itchy cat will pull out her hair. Ear infections are occasionally seen. Cats with food allergy also tend to show itching around the head and face. Itching tends to be year-round, not seasonal.

    Diagnosis and treatment

    Diagnosis of food allergy is made by conducting a food trial. This consists of feeding a food that contains a protein and carbohydrate source that the cat has never encountered before. Prescription pet food manufacturers offer diets that are designed for food-allergic cats, such as venison and green pea or duck and green pea. When undergoing a food trial, the cat can consume absolutely no other food items except the prescription diet and water or the results will be inconclusive. The diet should be fed for at least twelve weeks before making a final assessment of the response. Once the signs resolve, feeding the cat her original diet and seeing the clinical signs return will be definitive proof of food allergy.

    Your veterinarian may want to do some diagnostic tests to rule out other disorders that have similar clinical signs. These tests may include blood work, skin scrapings, fungal cultures, and a skin biopsy. Some veterinary laboratories offer a blood test for diagnosis of food allergy; most veterinary dermatologists, however, do not believe that these tests are accurate. Skin testing, which is accurate for diagnosing inhalant allergies in cats, is also ineffective for diagnosing food allergy. Conducting a hypoallergenic food trial is the only effective means of diagnosis. Once the diagnosis is made, treatment consists of avoiding the offending allergen and feeding only a hypoallergenic diet. Occasionally, a cat will develop an allergy to the new food. In these cases, switching to a diet with a novel protein and carbohydrate source may again be necessary. Some prescription pet food manufacturers offer a "limited antigen" diet, which is a diet in which the protein has been hydrolyzed (broken down and digested) into fragments that are small enough to escape detection by the immune system, thus preventing them from triggering an allergic response. These hydrolyzed diets may be necessary in cases of recurrent food allergy.

    Food allergies can be tricky to diagnose. Doing so involves feeding the cat proteins and carbohydrates she has never eaten before and checking her reaction.

    Most cases of food allergy develop after a cat has been fed the same food for a long time, not when the diet is changed.

    Flea Allergy

    Flea allergy dermatitis (FAD) is a very common skin disorder in cats.

    Causes and symptoms

    When fleas bite a cat, they inject saliva into the skin. Cats who are allergic to the flea saliva will become very itchy after being bitten and will scratch themselves repeatedly, damaging the skin and increasing the risk of acquiring a skin infection. Any area of the body can be affected, although the lower back and base of the tail are the most common spots. Cats with flea allergy may show miliary dermatitis- tiny little scabs throughout the hair coat. Hair loss is common, resulting from excessive licking or pulling of the fur. As few as one or two flea bites can trigger the reaction. Unlike food allergy, FAD tends to be seasonal, being worse during the summer and early fall.

    Diagnosis and treatment

    FAD is diagnosed based on the clinical signs in conjunction with the discovery of fleas or flea dirt on the cat, and the ruling out of other skin disorders. This may require various tests, including blood work, skin scrapings, fungal cultures, and skin biopsy. Intradermal skin testing, in which a small amount of flea antigen is injected into the skin, is a more objective measure of the presence of FAD, but this test is rarely necessary. Treatment includes strict flea control using topical once-a-month flea control products that kill fleas before they bite. All cats in the household should be treated. Frequent vacuuming of carpets and upholstery is beneficial in removing flea eggs and larvae from the environment. In cases of severe infestation, treatment of the premises with flea sprays or bombs may be warranted. Antibiotics Biblemay be necessary if a secondary bacterial skin infection is present. Corticosteroids, antihistamines, and omega-3 fatty acids may be beneficial for controlling itchiness and inflammation.

    Allergic Inhalant Dermatitis

    Allergic inhalant dermatitis (atopy) is an allergy to airborne substances such as pollens or dust. It is a common cause of itching in cats. In most cases, the itching is seasonal; however, many cats with atopy can be itchy all year round if the allergen persists in the environment.

    Causes and symptoms

    Atopy is an inherited disease, passed on to the cat by one or both parents. Although it can strike cats at any age, most cats begin showing signs of atopy when young, usually by one year of age. Cats with atopy are itchy and may show red, inflamed skin due to constant scratching, particularly around the face, feet, and ears.

    Diagnosis and treatment

    Diagnosing atopy can be challenging. Clinical signs that are seasonal are suggestive of atopy. Intradermal skin testing, in which tiny amounts of allergenic substances are injected into the skin and the reaction recorded, is the chief way in which atopy is diagnosed. Blood tests designed to test whether a cat is allergic to plants native to a particular geographic region, as well as to common household dust and mites, are thought to be inaccurate and unreliable. Intradermal skin tests should be performed by an experienced veterinary dermatologist because the skin response to the injections can be subtle and more difficult to interpret in cats than in dogs.

    To rule out other common causes of itching and hair loss in cats, your veterinarian may need to perform some tests, such as blood work, skin scrapings, fungal cultures, and skin biopsy. The ideal treatment for atopy is avoidance of the offending allergen, although this is rarely possible. Treatment may include antibiotics to treat secondary bacterial skin infection if present; corticosteroids, antihistamines, and omega-3 fatty acids to control itching; and soothing shampoos. Immunotherapy, in which the cat is given a series of allergy shots to modify the immune response to the offending allergens, is another possible therapy. The allergy shots are prepared by a veterinary dermatologist based on the results of the cat's individual intradermal skin test results.

    Flea allergy dermatitis is very common in cats. The best way to prevent it is to keep your cat indoors and practice strict flea control.

    Bacterial Skin Infection

    The term pyoderma means bacterial infection of the skin. Bacterial infections of the skin are uncommon in cats.

    Causes and symptoms

    Signs of bacterial skin infection may include red, itchy skin, miliary dermatitis (tiny little scabs throughout the skin), small pimples, and oozing or draining sores. Skin-fold pyoderma occurs in folds of skin that are difficult for the cat to keep clean. Persian cats are especially prone to develop skin-fold pyoderma within the facial skin folds. This "dirty-face syndrome" commonly seen in young Persian and Himalayan cats is thought to be an inherited disorder and is usually accompanied by waxy ear infections.

    Most cases of pyoderma in cats occur secondary to some other itchy skin problem. Flea allergy, for example, can cause itching, and the self-trauma that the cat causes when scratching can damage the skin, compromising the protective barrier function of the skin and allowing bacteria to colonize it. Cats who are immunosuppressed, such as those infected with FIV, are at increased risk for infections, including bacterial skin infections. The most common skin infections in cats are caused bacteria of the genus Staphylococcus.

    Diagnosis and treatment

    Diagnosis is usually made by visual inspection of the skin; however, culturing the skin, microscopic examination of the contents of a pustule, and skin biopsy are occasionally required to make a definitive diagnosis, especially if the infection recurs after treatment. Antibiotic therapy is the appropriate treatment for bacterial skin infections. Antibacterial shampoos may be beneficial in stubborn cases. Cats with red, inflamed skin lesions may require clipping of the hair around the affected area and cleaning with an antiseptic solution. The development, several years ago, of a long-lasting injectable antibiotic for the treatment of skin infections in dogs and cats has been a significant advance in pyoderma therapy. One injection lasts for fourteen days, alleviating the need to administer oral liquid or tablet antibiotics. This is a very welcome development for cat owners because cats can be challenging to medicate orally.


    Ringworm is the most common infectious skin disease in cats. Despite the name, ringworm is not a worm; it is a skin fungus. Microsporum canis is the species of ringworm that most commonly affects cats. Ringworm is a zoonotic disease-meaning it can be transmitted to people.

    Causes and symptoms

    Cats become infected with ringworm when they're exposed to infective spores through contact with an infected animal, a contaminated object, or a contaminated environment. Spores are small and may also be carried on air currents and on dust particles. Once the spores reach the coat, if they survive the cat's natural defense mechanisms (for example, grooming and sunbathing), they adhere to and invade cells called keratinocytes on the hair shaft and skin (and occasionally, the nails) and they germinate, initiating the infection. Hair shafts become weak, brittle, and easily broken. Hair fragments and skin scales are shed into the environment, along with thousands of spores. Spores can remain in the environment for months or years, serving as a reservoir of infectious material for humans and other cats brought into the environment.

    Many factors, including young age, concurrent disease, drugs that suppress the immune system, compromised immune status, poor nutrition, stress, and overcrowding will predispose cats to acquiring ringworm. Cats in animal shelters and catteries are much more likely to harbor ringworm than pet cats, and isolation of this fungus from even one cat or kitten in a cattery warrants treatment of the entire cattery.

    Cats of any age, sex, or breed are susceptible to infection. Kittens and geriatric cats, however, are more frequently affected, as are longhaired cats. Longhaired cats are believed to be more susceptible because the long hairs protect the spores from being removed by grooming. Long hair can get matted, and matted hairs are also more susceptible to ringworm infection. When cats groom themselves, they're engaging in an important activity that helps limit ringworm infection. Kittens in general are the most susceptible population, with the head, face, ears, and forelimbs primarily involved. It is speculated that the face and ears are commonly affected spots in kittens because these areas, although groomed well by the mother, tend to be not very well groomed by kittens. Interestingly, lesions often appear in kittens at or around the time of weaning, which supports this hypothesis.

    Concurrent disease can have an effect on the susceptibility to infection. For example, cats infected with FIV are three times more likely to acquire ringworm than are uninfected cats. Genetics may also play a role in a cat's susceptibility to ringworm. Studies have shown that chronic ringworm problems are most common in catteries in which members were genetically related, and breeders may be unintentionally selecting for susceptible cats when they breed for certain coat characteristics.Grooming is one way that cats help to remove ringworm spores from their coat. Persians, Himalayans, and other longhaired cats tend to be less efficient groomers, making them more inclined to acquiring ringworm infection. Genetic influences, however, may play a role in these breeds as well.

    The classic clinical appearance of ringworm includes one or more areas of patchy hair loss with mild or moderate crusting, but ringworm in cats can have a wide variety of presentations. Infected cats can present with any combination of the following:

    • blackheads-ringworm infection occasionally causes blackheads on the chin in young cats
    • crusting and scaling-ringworm lesions tend to be exfoliative. Usually, the scaling is mild, but in some cats it's quite severe.
    • hair loss-ringworm causes hair loss; this may be subtle or dramatic, and may show a symmetrical pattern or be totally asymmetrical
    • hyperpigmentation-ringworm infection can cause a darkening of the skin in some cats
    • nail infection only-a few cats with ringworm develop crusty or greasy nail infections as their only clinical sign of ringworm.
    • overgrooming-cats with hair loss from apparent overgrooming will sometimes be found to have ringworm infection.
    • pruritus (itchiness)-in general, ringworm is not an especially itchy disease, although some cats have mild itchiness, while others are severely itchy and will scratch to the point of self-mutilation.
    • redness-areas of hair loss are often reddened when they first develop.

    Feral kittens commonly have ringworm, something that anyone who works in shelters or does cat rescue should be aware of.

    Himalayans and other longhaired cats tend to be less efficient groomers, making them more inclined to acquire ringworm infection.

    Diagnosis and treatment

    Diagnosis is made through fungal culture. Hairs from affected areas are plucked with a sterile hemostat and placed on a special fungal culture medium. If the ringworm fungus starts to grow on the culture medium in a few days, the diagnosis is confirmed. Shining a fluorescent light, called a Wood’s lamp (named for its inventor, physician Robert W. Wood), on the hair coat may help better identify infected hairs, for better sampling for the fungal culture. Half of the strains of Microsporum canis will glow apple-green under the lamp.

    Cats who test positive for ringworm need some kind of treatment. Treatment plans may vary somewhat for each cat, but all plans involve some combination of clipping the hair coat, topical therapy, systemic (oral) antifungal medication, and environmental decontamination. Environmental decontamination suggestions when treating ringworm include:

    • Discard all blankets, brushes, cat rugs, collars, and fabric toys.
    • Discard any cat objects that cannot be easily disinfected, repeatedly scrubbed, and/or frequently vacuumed.
    • Purchase a new, inexpensive vacuum cleaner with hose attachments that can be thoroughly cleaned.
    • Remove and clean all drapes and decorations. In multicat households, remove and clean all heating duct and vent plates, and install disposable house dust filters behind the duct plates before replacing them. This will keep spores out of the heating ducts.
    • Put a fan in the window, if possible, so that it draws air out of the room to the outside.
    • Vacuum all surfaces of the room.
    • Dust all surfaces and ledges with a disposable electrostatic cloth (such as a Swiffer).
    • Scrub all surfaces with a detergent that is safe to use around cats. Rinse all surfaces well. Apply a 1:10 dilution of bleach to all nonporous surfaces. Leaving the bleach solution on the surface for fifteen minutes is ideal.
    • Using a portable dehumidifier is beneficial because humid environments allow spores to remain viable.

    Step 1 of therapy involves clipping the hair coat. Clipping the coat removes infected hairs and minimizes continued shedding of hair fragments and spores. It also allows for more thorough penetration of topical antifungal shampoos. As a general rule, if a shorthaired cat has five or more discreet spots of ringworm, the entire coat should be clipped. If a shorthaired cat has fewer than five discreet spots, the hair around the individual spots can be clipped. If the cat is longhaired, the entire coat should be clipped regardless of how many discreet ringworm spots are visible on the coat. Once the coat is clipped, cats are ready to undergo topical therapy with a medicated shampoo. Topical therapy minimizes the spread of infective spores into the environment and helps remove infective crusts, scales, and spores from the coat. Without topical therapy, treatment will take longer and will be more costly.

    There are many effective topical products. Shampoos containing a combination of miconazole and chlorhexidine are very effective against ringworm. Cats should be bathed twice weekly. For the shampoo to be effective, it is important that there be a contact time of ten minutes with the cat's fur. The cornerstone of treatment for ringworm is systemic therapy with an oral medication. Drugs that have been shown to be effective include griseofulvin, itraconazole, ketoconazole, and terbinafine. Cats receiving treatment for ringworm usually show marked improvement in clinical signs within two to four weeks of therapy. Four weeks after beginning treatment, cats should be reexamined. A fungal culture should be performed at every recheck. Once a negative culture is obtained, weekly fungal cultures should be performed. Two consecutive negative fungal cultures indicate successful treatment.

    Ringworm spores can persist in the environment for a long time, perhaps eighteen to twenty-four months. The spores are microscopic and can be spread easily by air currents and contaminated dust, and through heating ducts and vents. To minimize environmental contamination in households where only one single pet cat is infected, the cat or kitten should be kept in a small, easily cleaned room (such as a bathroom) that does not have carpeting. The cat should be quarantined in this room until it has received oral antifungal medication for two weeks, and a minimum of four medicated baths. At this point, the cat can be given greater access in the home, ideally in uncarpeted and easily cleaned rooms. Thorough and repeated vacuuming and wiping of surfaces on a daily basis should prevent the home from becoming contaminated. Cat beds and blankets should be washed daily in hot water and bleach. Bathrooms and smooth surfaces can be disinfected with a bleach solution (1 part bleach, 9 parts water). Routine cleaning and disinfecting should continue until the cat is considered cured of ringworm. Indoor cats are unlikely to become reinfected once the ringworm is treated successfully.

    Shampoos containing a combination of miconazole and chlorhexidine are very effective against ringworm.

    EGC can be triggered by an allergic response to mosquito bites, but most of the time, the underlying cause is never discovered.

    Eosinophilic Granuloma Complex

    The eosinophilic granuloma complex (EGC) is a collection of skin disorders that are often grouped together because they have the same basic underlying characteristic-infiltration of the skin by eosinophils. An eosinophil is a type of inflammatory blood cell that is commonly associated with allergic or parasitic diseases. There are three manifestations of the feline EGC: the indolent ulcer, the eosinophilic plaque, and the eosinophilic granuloma.

    Causes and symptoms

    The cause of EGC is not known; however, an underlying allergy such as flea allergy, atopy (allergy to inhaled environmental allergens), or food allergy has long been suspected. A genetic predisposition to EGC has also been postulated. In some cases, EGC are triggered by an allergic response to mosquito bites. Most of the time, the underlying allergen is never discovered. Any age cat may be affected, but EGC is most common in young to middle-aged cats. In some cats, more than one type of eosinophilic skin disease can occur at the same time.

    The indolent ulcer (sometimes referred to as rodent ulcer) commonly appears as an eroded spot on the margin of an upper lip. Both lips can be affected, but in most cases, it is unilateral. The ulcers appear reddish brown and are well-demarcated and hairless. Sometimes they are painful and affect a cat's willingness to eat. Eosinophilic plaques can appear anywhere on the skin, but they are most commonly found on the abdomen and the inside thighs. They may be singular, or there may be multiple lesions. They appear raised, red, moist, and well circumscribed. They are very itchy, and cats lick them constantly. Analysis of the blood often reveals an increased number of eosinophils in the bloodstream as well. Eosinophilic granulomas (also called linear granuloma or collagenolytic granuloma) often occur down the back of the thigh, on the face, and in the mouth, especially on the tongue or the roof of the mouth. When they occur on the skin, they tend to be yellow or pinkish in color, raised, hairless, with a characteristic linear configuration. When they occur on the face or in the mouth, they tend to appear more nodular. One manifestation is to cause the lower lip to swell, giving the appearance of a "fat lip."

    Diagnosis and treatment

    Diagnosis of eosinophilic skin disorders is usually made based on their visual appearance. However, a biopsy is sometimes necessary to rule out disorders with similar appearances. The optimal treatment is avoidance of the offending allergen. Strict flea control is essential because flea allergy may be a potential trigger for EGC. A feeding trial with a hypoallergenic diet may be needed to identify an underlying food allergy. In most cases, the allergen cannot be identified, and administration of immunosuppressive drugs is necessary to control the clinical signs. These drugs can be given in pill form or as a long-acting injection. The prognosis varies, with young cats often having a better prognosis.

    Keeping your cat indoors will reduce the chance she will ever become infested with lice or mites.

    Hair Loss

    The medical term for hair loss is alopecia. There are many possible reasons for hair loss in cats. Spontaneous hair loss (that is, the hair is falling out) can be the result of systemic diseases, especially glandular disorders. This is common in dogs, but uncommon in cats. Self-inflicted hair loss is the more common scenario in cats. Cats will lick, bite, or pull their hair out because the skin feels itchy or for a variety of psychological reasons. There are numerous causes for itchy skin, with parasitic infestations, fungal infections, and hypersensitivities/allergies being some of the more common reasons.

    Parasitic Infestations

    External parasites such as lice, mites, and fleas will always be a problem for companion animals. Few creatures living on earth today have had as much impact on world history as the common flea. From the black plague during the fourteenth century to the present day, fleas have been the cause of much grief. They make your cat itch, especially if she is allergic to flea bites, which is quite common. External parasites are a well-known cause of hair loss in cats.

    Causes and symptoms

    Pediculosis (lice infestation) has been reported to cause itching and hair loss in cats, although the condition is quite uncommon. Infestation with scabies mites is uncommon in cats, although it has been reported in cats with potentially immunosuppressive disorders, particularly FIV infection. Signs of scabies infestation varies widely, with some cats barely showing any itchiness and others showing intense skin discomfort and subsequent hair loss from overzealous grooming. Demodicosis (infestation with mites of the genus Demodex) can cause itching and hair loss, although it, too, is relatively uncommon in cats.

    Flea infestation and flea allergy, however, are very common causes of hair loss in cats. Fleas deposit their saliva into a cat's skin before they draw their blood meal, and flea-allergic cats may show a severe reaction to the saliva, even from one flea bite. The itching can be intense, and cats may lick and chew excessively at their skin, especially around the base of their tail.

    Diagnosis and treatment

    Parasitic infestations are diagnosed by carefully inspecting the skin for parasites (such as fleas), as well as by performing skin scrapings and microscopic examination to look for mites. Flea problems should be suspected if fleas or flea dirt is noted during the exam. Even if fleas are absent, flea allergy can be issue. For cats who are allergic to flea bites, it only takes a single bite to produce an intense and sometimes prolonged reaction.

    Flea infestation is easily remedied with once-amonth topical flea control products. These products can be obtained only through your veterinarian. (Do not purchase over-the-counter monthly flea control products from drug stores or pet stores. These often mimic the veterinary products in appearance, but may contain insecticides that can cause serious harm to your cat.) Cats with severe inflammation and itching may experience some relief with a short course of oral corticosteroids and/or antihistamines.


    Allergies are a common reason why cats overgroom and pull out their fur. Flea allergy, food allergy, and atopy (allergy to airborne substances) are the three common causes of allergy in cats.

    Causes and symptoms

    Adverse reactions to food may manifest themselves via the skin. Severe generalized itching; tiny little scabs and crusts throughout the hair coat (called miliary dermatitis); itching around the head, neck, ears, and face; and self-inflicted hair loss due to overgrooming may be seen. Food allergy may show up first in the skin as small red spots. These can turn into scabby or crusty sores that become infected as the cat rubs or scratches them. Allergies to airborne substances, such as pollens or dust, can lead to itching and subsequent excessive grooming and hair loss. Itching that is seasonal is suggestive of atopy, although many cats with atopy can be itchy all year-round as well.

    Diagnosis and treatment

    Itching around the head and face is a common sign of food allergy in cats; however, there are many cats whose only sign Bibleof food allergy is self-induced hair loss. Dietary elimination trials, in which the cat is fed a diet containing a protein source she hasn't encountered before (such as duck, rabbit, or venison) are necessary to obtain a definitive diagnosis. These trials require patience on the part of the cat owner, as it may take anywhere from three to twelve weeks before improvement is noted.

    Making a diagnosis of atopy can be challenging. Blood tests can be performed to see if the cat is allergic to plants that are native to a particular geographic region, as well as to common household dusts and mites, although many dermatologists feel the blood tests to be unreliable. Intradermal skin testing, in which tiny amounts of allergenic substances are injected into the skin and the skin reaction noted, is a more meaningful diagnostic test. Dust mites and molds are the most common airborne allergens, with some cats having concurrent reactions to seasonal pollens. Intradermal skin tests should be performed by an experienced veterinary dermatologist.Cats who are diagnosed with food allergy should continue to be fed their hypoallergenic diet.

    Specific treatment of an airborne allergy is possible if the allergen(s) can be identified and avoided or removed from the environment. Often, this is not practical, especially in patients allergic to airborne pollens. Hyposensitization—serial injections of progressively larger amounts of the offending allergen—is probably the most appropriate long-term control method for cats with a prolonged allergy season. Other therapies that can be considered are antihistamines, omega-3 fatty acids, and corticosteroids. Although steroids have the potential to have side effects, the doses necessary to control allergic dermatitis are unlikely to cause problems, especially in cats, because cats are more resistant to the undesirable side effects of steroids than are dogs.

    Fungal Infection

    The fungal infection best known to cause hair loss in cats is ringworm.

    Causes and symptoms

    Ringworm, as noted earlier, is the most common infectious skin disease in cats, and it may cause hair loss. Any age, sex, or breed of cat may be affected, although young cats, older cats, and longhaired cats are more frequently affected. Although ringworm, in general, is not thought of as an especially itchy condition, this is very variable. It can cause a lot of itching in some cats, so one has to consider ringworm in the list of itch-inducing skin disorders in cats. The itching may occasionally result in self-induced hair loss.

    Diagnosis and treatment

    Ringworm is a zoonotic disease-it can be transmitted to humans. If your cat has a circular crusty skin rash, and you have a similar rash, you can be almost certain that ringworm is the culprit. A definitive diagnosis is achieved through fungal culture. Ringworm treatment options vary, depending on the situation (an individual cat vs. cattery or multiple-cat household, longhaired cats vs. shorthaired cats), but may involve some combination of clipping the coat, topical therapy (usually shampooing), oral medication, and environmental decontamination. Treatment is often successful if clients are diligent about following the prescribed protocols.

    Cat showing evidence of self-inflicted hair loss or overgrooming. A variety of physical and psychological problems can cause this behavior.

    Tearing Their Fur Out

    "I've been tearing my hair out over this!" Sound familiar? If you haven't said it yourself, you've certainly heard other people use the phrase when they are frustrated or anxious over a situation. Fortunately (in most cases anyway), they're not speaking literally, and no bald patches appear on their heads.This is not the case with cats, however. Stressed or anxious cats often pull, chew, or excessively groom their fur. In fact, psychological disturbances are a very common cause of self-inflicted hair loss in cats. In many instances, the cause of a cat's stress is obvious: a move to a new apartment, a short stay at a boarding facility, a new pet or baby in the household, territorial competition in a multiple-cat household, to name a few examples. In some cases, the cause of the stress is not so obvious to us.

    Grooming is a comfort behavior, often used by cats to relax themselves. Think about the last time your cat did something foolish or klutzy, like misjudge a leap or accidentally tumble off the sofa. We might chuckle, but the cat immediately grooms. Whether they feel embarrassment is debatable, but cat lovers recognize this reflexive grooming behavior in their cats whenever uncertainty arises. It shouldn't be surprising that, in the face of stress, they may turn to excessive grooming to dispel their anxiety. Once parasites, allergies, and other medical problems have been ruled out, psychogenic alopecia-hair chewing and overgrooming due to psychological factors such as stress, fear, anxiety, or nervousness- must be considered. Psychogenic alopecia is a diagnosis of exclusion. Cats of Asian lineage (Siamese, Abyssinians, Burmese. and Himalayans) are apparently more susceptible to psychogenic alopecia, presumably because of their high-strung, nervous temperaments. Ideally, the treatment of psychogenic alopecia would involve the elimination of the potential stressors in the cat's environment. Unfortunately, this is often impossible or impractical, and antianxiety or antidepressant medications are often warranted to control the problem.

    Ears and Hearing Injuries and Disorders

    Ears and Hearing Injuries and Disorders

    Although ear infections are not as common in cats as they are in dogs, they do occur. If untreated, some can lead to compromised hearing and deformity.

    Ear infections are more common in dogs than in cats.

    Otitis Externa

    Otitis externa refers to any inflammatory disease of the external ear canal, although the term is mostly used to describe an outer ear infection. Most ear infections are due to bacteria.

    Causes and symptoms

    Most cases of ear infection occur secondary to some other disease state or because of some predisposing factor. Foreign bodies (such as plant material, dirt, sand), parasites (such as ear mites), trauma (excessive scratching by the cat), food allergy, ear canal tumors, atopy or some other kind of general skin disease, and excessive moisture in the ear are examples of possible causes of ear infections in cats. Once the skin inside the ear is compromised, bacteria and yeast that normally live in the ear can overgrow, causing an infection. The inside of the ear can become red, and a foulsmelling discharge can develop. Cats will often shake their heads, scratch at their ears, and react in pain when their ears are touched or rubbed. Severe, untreated infections can result in stenosis (a narrowing or closing) of the ear canal.

    Diagnosis and treatment

    A diagnosis is usually made on physical examination. Your veterinarian will look into the ear with a device called an otoscope to identify ear mites, the degree of debris buildup, foreign bodies, tumors or polyps, and whether the eardrum is intact. In some cats, this might require sedation. Examination of exudate (a mixture of fluid, cells, and debris) from the ear under the microscope provides immediate diagnostic information and helps determine the types of microorganisms and parasites that might be present within the canal. A culture of the exudate from the canal allows identification of any bacteria that might be causing infection. Yeasts do not usually grow on culture; yeast is best identified on microscopic examination of the exudate. If a tumor is visible in the ear canal, a biopsy may be necessary to identify the type of tumor.

    Successful treatment requires correcting any underlying factors; accurately identifying specific bacteria, yeast, parasites, or foreign bodies in the ears; thoroughly cleaning all of the debris, exudate, and wax from the ears; and administering the proper medications at home. Antibiotics are indicated when a bacterial infection is present. Antibiotics are given topically (instilled into the ear). In some cases, oral antibiotics are given in addition to the topical ones. Topical antifungal medication is given when fungal (yeast) infections are present. Insecticides are given (either in the ear or on the skin) if ear mites are identified.

    Otitis Media and Otitis Interna

    Otitis media refers to infection of the middle ear; otitis interna refers to infections of the inner ear.

    Causes and symptoms

    Otitis media occurs, in most cases, when an external ear infection breaks through the eardrum and enters the middle ear. Other possible causes include polyps, tumors, and the spread of an upper respiratory infection from the throat, up the eustachian tube, and into the middle ear. Middle ear infections can extend into the inner ear, where the vestibular system resides, causing problems with balance and coordination. Signs of otitis media include shaking of the head and pawing at the ear, similar to that seen with otitis externa. Running through the middle ear is the facial nerve; when it is affected by otitis media, paralysis of the lip on the infected side occurs and a decreased or absent blink reflex of the eye on the affected side may be seen. If the inner ear becomes involved, cats may develop a head tilt and an uncoordinated gait, in which they lean, stumble, or fall when they walk.

    Diagnosis and treatment

    Diagnosis is made mainly by clinical signs. Head shaking, a head tilt, circling, rolling, stumbling, leaning to one side, involuntary beating of the eyes from side to side (this is called nystagmus), or signs of facial nerve abnormalities strongly suggests otitis media and/or otitis interna. Other signs may include pain when the head is touched or when the mouth is opened. Examination of the ear canal with an otoscope may reveal a ruptured or bulging eardrum. If the eardrum is bulging, a procedure called myringotomy, in which the eardrum is punctured with a needle, may be helpful for draining the fluid, obtaining samples for microscopic evaluation and culture, and flushing the middle ear. X-rays of the skull, taken with the cat under anesthesia, can reveal changes in the bony structures that house the ear. If they are available, computed tomography (CT) or magnetic resonance imaging (MRI) scans provide additional useful diagnostic information. Treatment involves administering antibiotics orally for four to six weeks. In recurrent or nonresponsive cases, surgery may be necessary.

    Nasopharyngeal Polyps

    Nasopharyngeal polyps are benign growths that can arise from several sites, including the nasopharynx (the back of the throat); the nose, where they occupy the nasal cavity; the middle ear, where they can break through the eardrum and enter the external ear canal; and the external ear canal itself, usually very close to the eardrum.

    Causes and symptoms

    The cause of the polyps is unknown. Nasopharyngeal polyps are most commonly seen in young cats, usually less than two years old. The clinical signs can vary depending on the location of the polyp. Cats with polyps in the nasal cavity often have loud, noisy breathing; heavy snoring; frequent sneezing; chronic nasal discharge; and occasional problems with swallowing. In the middle ear, they can affect balance and hearing. If she has a polyp in an ear canal, a cat may have discharge from the ear and an ear infection. A foul smell may be noted coming from the ear canal. A polyp in the ear may be misdiagnosed as a simple ear infection that does not respond to antibiotics. Nasopharyngeal polyps should be suspected in any young cat with very noisy breathing, chronic sneezing, nasal discharge, and difficulty swallowing. Polyps that occur in the nasal cavity may cause a downward displacement of the soft palate, which may be visible when the oral cavity is examined.

    Diagnosis and treatment

    Polyps that occur in the external ear canal may be seen with an otoscope. X-rays of the skull often reveal the presence of a polyp. If available, CT and MRI images are superior imaging techniques for detecting polyps, especially if the middle ear is involved. If the mass is above the soft palate, rhinoscopy, in which a flexible tube with a camera on the end is inserted into the mouth and then flexed backward, may allow direct visualization of the polyp. Treatment involves grasping the polyp with forceps at the base and applying gentle traction until the polyp is removed. Failure to remove all of it may result in regrowth. If a CT scan or an MRI shows a polyp in the bulla (the bony structure surrounding the middle ear), surgery should be performed to open the bulla and remove the polyp. This surgery is called a bulla osteotomy.

    If your young cat has noisy breathing, chronic sneezing, and difficulty swallowing, she may have nasopharyngeal polyps and will need veterinary care.

    Aural Hematomas

    An aural hematoma is a collection of blood that has accumulated between the inner and outer surfaces of the ear.

    Causes and symptoms

    Aural hematomas are believed to be caused by trauma, such as excessive shaking or scratching of the ear. Common reasons for excessive shaking and scratching are severe ear infection or ear mite infestation. Normally, the inner surface of the pinna (the external, visible part of the ear) is firmly attached to the skin. After trauma, hemorrhage occurs and accumulates between the cartilage and the skin. The blood dissects the skin away from the cartilage, forming a hematoma or pocket of blood. The pinna appears swollen, bulging mainly inward, partly occluding the ear canal. If left untreated, the hematoma matures and contracts, causing the ear to become thickened and deformed-the so-called cauliflower ear.

    Diagnosis and treatment

    Diagnosis is made on physical examination, where a large, warm, fluidfilled swelling is noted on the ear. A concurrent ear infection may also be noted. Aural hematomas are treated surgically. Any underlying problem, such as ear mite infestation or an ear infection, needs to be treated as well. Surgery will remove the hematoma, and it offers the best chance of retaining the natural appearance of the ear.

    Eyes and Vision Injuries and Disorders

    Eyes and Vision Injuries and Disorders

    The eyes are important and delicate organs. A veterinarian should be consulted-ideally within twelve hours-when an eye problem is suspected. Signs of an eye problem include squinting, tearing, swelling or redness of the eyelid or eyeball, protrusion of one or both eyes, or discharge from one or both eyes. If left untreated, many eye conditions can lead to visual impairment or even blindness, thus any abnormality should be reported to a veterinarian. Some of the most common eye disorders in cats include cataracts, conjunctivitis, corneal ulcers, glaucoma, and uveitis (inflammation of the inner layer of the eye). The third eyelid (known as the nictitating membrane in medical jargon) is a membrane located in the inside corner of the eye. It produces a portion of the tear film, helps distribute this tear film over the surface of the cornea, and protects the cornea from damage. Elevation of the third eyelid on one side only is often a sign of local irritation or trauma to that eye. General malaise from a variety of systemic illnesses can cause bilateral elevation of the third eyelid (often described by cat owners as a "film over the eyes"). Whenever this symptom appears, a thorough ocular and systemic examination is warranted.

    If left untreated, eye conditions can lead to visual impairment, so seek prompt veterinary care if your cat show signs of an eye infection.

    Veterinarian examining a cat who may have conjunctivitis.

    Eyelid Problems

    The eyelids of the cat, like those of humans and other animals, are designed to protect the eye. Although eyelid disorders are uncommon in cats, they do occur. Examples of eyelid disorders include blepharitis (inflammation of the eyelid) and eyelid agenesis (a birth defect in which the eyelids are missing).

    Causes and symptoms

    The most common eyelid defect in cats is entropion, a rolling inward of the edge of the eyelid, usually the lower lid. Entropion can affect one eye or both. Some cases are breed associated, especially in purebred cats with flat faces, such as Persians and Burmese. Entropion can also occur secondary to other conditions, such as spasm of the eyelid in cats with painful corneal ulcers, or as a result of chronic herpes virus infection. When the eyelid rolls inward, the hair on the eyelid rubs against the cornea, causing continual discomfort and irritation. Clinical signs include tearing, squinting, rubbing at the eyes, redness or swelling of the tissues surrounding the eyes, and wetness on the hairs adjacent to the eyelids.

    Diagnosis and treatment

    Entropion is diagnosed on physical examination. Surgery is required to roll the eyelid outward and correct the condition. This should be done by a veterinarian with experience in this technique.

    Corneal Ulcers

    Corneal ulceration is a painful and potentially vision-threatening condition that occurs when the corneal epithelium (the outermost layer of cells on the cornea) is damaged or lost.

    Causes and symptoms

    Superficial ulcers can occur as a result of trauma, such as from a fight with another cat, or as a result of herpes virus infection. Other causes include abrasion from hairs on the eyelid (entropion-see above), foreign bodies, and chemicals. Although any cat can be affected, breeds with naturally bulging eyes (such as Persians) are at increased risk. Regardless of the cause, ulcers must be treated promptly. The feline cornea is only 0.5 millimeters thick. Delaying therapy for corneal ulcers can result in perforation, leading to blindness. Signs that a cat might have a corneal ulcer include squinting, discharge from the eye, rubbing at the eye, excessive tear production, and inflammation of the soft tissues surrounding the eye.

    Diagnosis and treatment

    Diagnosis of a corneal ulcer is achieved through special staining techniques. A drop of a fluorescent dye is placed on the cornea. If the cornea is intact, the dye washes over the eye as a smooth film. If a scratch or abrasion is present on the cornea, the dye will adhere to the exposed tissue layer beneath the corneal epithelium, making the ulcerated area fluoresce bright green and allowing assessment of the size and depth of the ulcer. BibleCorneal ulcers are treated with antibiotic drops or ointment to prevent the cornea from becoming infected. Antiviral drops or ointment may be indicated if herpes virus infection is suspected. Atropine drops or ointment is administered to the eye to dilate the pupil and paralyze the ciliary muscle of the eye, preventing painful spasm. An Elizabethan collar may be necessary to prevent the cat from rubbing the eye and causing further damage. Deep corneal ulcers may require surgery to prevent potential rupture of the eye. A soft contact lens is sometimes warranted to protect the cornea from further damage. Oral antiviral medication, as well as the amino acid lysine, may be helpful in the treatment of ulcers caused by feline herpes virus. Most superficial, uncomplicated ulcers heal within seven days. Deep ulcers and nonhealing or progressive ulcers may require ongoing evaluation by a veterinary ophthalmologist.

    Administering Eye Medication

    Therapy for most eye disorders entails administering drops or ointments. Drops are often easier to administer, although many drops require frequent administration. Ointments have the advantage of providing lubrication and allowing for increased contact time for the medication; they are especially useful given at bedtime. Application involves using the thumb or forefinger to gently roll the cat's lower eyelid downward. Ointment is then squeezed into the exposed space (called the conjunctival sac), and the eye is opened and closed by hand several times to evenly distribute the ointment over the eye. Approaching the eye from the outside corner can prevent the cat from seeing the tip of the tube, making administration a bit easier. Eye drops are instilled with the cat's nose tilted slightly upward. To prevent contamination, the tip of the dropper bottle or ointment tube should not be touched by fingers or any other surface; to prevent injury it should not come into direct contact with the eye.


    Disorders of the conjunctiva— the membrane that lines the lids and covers the eyeball—are some of the most common eye conditions affecting cats. Inflammation of this structure is called conjunctivitis.

    Causes and symptoms

    By far the most common cause of conjunctivitis in cats is a viral upper respiratory infection (mainly the herpes virus and the calici virus). Bacterial infections of the conjunctiva often develop secondarily in cats with viral conjunctivitis, as bacteria take advantage of the inflamed conjunctiva and colonize the eye. Chlamydophila (formerly Chlamydia) is a common cause of bacterial conjunctivitis in cats. Herpes conjunctivitis is usually bilateral, whereas Chlamydophila often begins in one eye and progresses to bilateral involvement in about a week. Kittens are particularly susceptible. Other reasons for conjunctivitis include any other cause of infection and inflammation of the eyelids and cornea, as the conjunctiva is so closely associated with these structures.Signs of conjunctivitis include redness of the eye, excessive squinting or blinking, and discharge from the eye. If concurrent upper respiratory infection is present, sneezing, nasal congestion and discharge, fever, lethargy, and poor appetite may also be present.

    Diagnosis and treatment

    Diagnosis is based on physical examination findings of a red, inflamed conjunctiva. Treatment of conjunctivitis involves treating any underlying causes, if identified. Topical antibiotic and antiviral drops or ointments are the standard treatment. Oral medications may be recommended in severe cases. Lysine, an amino acid, may be beneficial in treating conjunctivitis due to the herpes virus.

    The treatment of conjunctivitis varies depending on the cause.


    Glaucoma is excessive pressure inside the eyeball. The normal pressure inside the eye is maintained through a delicate balance in the production and exit of aqueous humor, a watery fluid inside the eye.

    Causes and symptoms

    Glaucoma occurs if the normal outflow pathway of aqueous humor becomes obstructed. If the fluid cannot drain properly, the pressure in the eye increases, causing damage to the retina and optic nerve. This ultimately leads to vision loss. Primary glaucoma is a type of glaucoma that occurs spontaneously, for no apparent reason. In cats, this type is uncommon. The more common form is secondary glaucoma, in which the condition occurs secondarily to some other eye disorder, such as inflammation, displacement of the lens, trauma, or cancer. Signs of glaucoma include an enlarged bulging eye, squinting, tearing, redness, a cloudy or "steamy" appearance to the cornea, and a dilated pupil. Most cases are unilateral (one eye affected).

    Diagnosis and treatment

    A diagnosis is made by measuring the pressure inside the eye with an instrument called a tonometer. Normal pressure within the eye is 15–25 mm Hg. Elevated pressure inside the eye (greater than 25 mm Hg) confirms the diagnosis. A thorough eye examination is necessary to determine if concurrent eye diseases are present because glaucoma can occur secondarily to other eye problems, and correcting the underlying problem may help control the glaucoma. Treatment is either medical or surgical. Medical therapy consists of giving medication, both oral and topical, to decrease the production of fluid inside the eye and to reduce eye inflammation. If medical therapy isn't successful, surgery can be attempted. Surgery is aimed at destroying the structure in the eye that produces aqueous humor. This is achieved through cryosurgery (freezing) or laser surgery. In cases in which the glaucoma cannot be controlled, or those in which the glaucoma is caused by a tumor in the eye, enucleation (surgical removal of the eyeball) may be necessary. The prognosis for glaucoma is guarded. Glaucoma is difficult to treat. Medications are necessary for the rest of the cat's life and must be given at the proper intervals.

    If your cat contracts an infectious eye condition, you may need to administer eye drops.


    A cataract is a cloudiness or opacity of the lens of the eye. The function of the lens is to focus light onto the retina in the back of the eye. To do this properly, the lens must be clear. A cataract within the lens may block the transmission of light onto the retina, affecting vision. Cataracts are much less common in cats than they are in dogs.

    Causes and symptoms

    Most cataracts develop secondary to some other eye problem, such as inflammation. Trauma is another cause of cataracts. Any penetrating injury to the eye has the potential to cause a cataract. Diabetes can result in cataracts in dogs, but not in cats. Inherited cataracts are rare in the cat. As cats get older, the lens can become cloudy simply as a result of aging. This benign condition, called nuclear sclerosis, is often mistaken as cataracts. Unlike cataracts, however, it does not affect vision. Signs of cataracts may include a white or gray color change within the eye, redness or inflammation of the eye, signs of pain or squinting, or signs of blindness (such as bumping into things, reluctance to jump on furniture, avoidance of the stairs).

    Diagnosis and treatment

    Diagnosis is usually made during a complete eye exam with your regular veterinarian; however, consultation with a veterinary ophthalmologist may be necessary. Surgery is the only option to restore vision. Whether a cat is a candidate for cataract surgery can be determined by a veterinary ophthalmologist. There is no medical treatment to reverse or shrink a cataract. Because most cataracts in cats are a result of some underlying systemic disease, cats with cataracts should be evaluated thoroughly by a veterinarian for concurrent illness.

    Feral kitten with severe eye inflammation and secondary cataracts.

    Retinal Detachment

    Retinal detachment occurs when the retina at the back of the eye peels away from the layer beneath it.

    Causes and symptoms

    The most common cause for this is high blood pressure. When cats have high blood pressure, fluid will leak out through blood vessels beneath the retina. This fluid accumulates beneath the retina, causing the retina to detach from the underlying layer. High blood pressure in cats is usually caused either by chronic kidney failure or by hyperthyroidism. Less commonly, retinal detachment can occur secondary to conditions that cause excessive viscosity or thickness of the blood. Excessive viscosity can occur in certain cancers, such as multiple myeloma or leukemia, or from excessive production of red blood cells (a condition called polycythemia). Retinal detachment may also occur if blood accumulates beneath the retina. This can happen if the cat has a blood clotting disorder, such as a low platelet count, or because of the ingestion of some types of rat poison. Trauma to the eye, with subretinal hemorrhage, can lead to detachment. Any infection that causes retinal inflammation can lead to retinal detachment, for example, fungal infections such as histoplasmosis and cryptococcosis. Congenital retinal detachment (being born with detached retinas) is another possibility, but this is rare in cats.

    Cats with retinal detachment will experience vision loss in the affected eye. The amount of vision loss depends on the severity of the detachment. If only one eye is affected, it may be difficult to tell if the cat is blind in that eye. If only a small section of the retina is detached (partial detachment), the cat often retains some degree of vision. Detachment secondary to high blood pressure is usually sudden in onset and affects both eyes.

    Diagnosis and treatment

    The most striking clinical sign of retinal detachment is widely dilated pupils that do not respond to a bright light. Evaluation of the retina using either an instrument called an ophthalmoscope or using a bright light and a special hand-held lens confirms the diagnosis. Some cases are difficult to diagnose, however, and may require special instrumentation and consultation with a veterinary ophthalmologist. Once a diagnosis of retinal detachment is made, further tests may be necessary to determine an underlying cause. Since high blood pressure is the most common cause of retinal detachment, measurement of the blood pressure is of paramount importance. Other tests include a chemistry panel and urinalysis to determine if kidney failure is present and thyroid hormone measurement to check for hyperthyroidism. Blood clotting assessment, chest and abdominal x-rays, and other tests may be warranted.

    Treatment involves addressing the underlying cause if possible. The detachment itself is difficult to treat. Detachments due to high blood pressure should be addressed immediately because a rapid normalization of the blood pressure may lead to partial reattachment and some restoration of lost vision. Depending on the cause of the detachment, other therapies may include antibiotics or antifungal drugs for bacterial and fungal infections, respectively. Chemotherapy may be warranted in some cases that are caused by cancer. Vitamin K therapy is the treatment for rat-poison induced hemorrhage. Hyperthyroidism is treated with oral medication, surgery, a prescription diet, or radioactive iodine.

    Dental Problems

    Dental Problems

    Dental problems are among the most common medical conditions seen in pet cats. They can lead to bad breath, swollen and bleeding gums, loose teeth, oral pain, and difficulty eating. Cats are secretive by nature, and sometimes it can be difficult to tell if a cat is experiencing oral discomfort. Occasionally, cats will reveal that their mouths are hurting by pawing at them, drooling, or deliberately turning their heads to one side as they eat to avoid chewing on the side of the mouth that's painful. Some cats will completely stop eating due to dental pain. Others may stop eating dry food and only eat wet food. Owners often mistakenly think their cats have become finicky about their food when in actuality the cats would prefer to eat the dry food but can't because it's become painful to crunch on kibble.

    Periodontal Disease

    Periodontal disease is an inflammation of the periodontium-the tissues surrounding the teeth.

    Causes and symptoms

    Periodontal disease is caused by plaque-the sticky bacteria-laden coating on the tooth surface-and the body's response to those bacteria and the toxins they release. As the immune system responds to the plaque, the gums become inflamed. This is the first phase of periodontal disease: gingivitis. As the inflammation progresses, the second phase of periodontal disease-periodontitis-occurs. Periodontitis is a condition in which both soft and bony tissues are affected, and cats may develop receding gums and experience bone loss. If not removed, plaque mineralizes into tartar (also called calculus) in a few days. Calculus requires mechanical removal by your veterinarian.

    Periodontal disease is very common in cats. Untreated, it can lead to oral pain, abscess formation, osteomyelitis (bone infection), and tooth loss. Oral bacteria can enter the bloodstream through diseased oral tissues, affecting other organs as well, most notably the heart valves and kidneys.

    Dental problems are among the most common medical conditions seen in pet cats.

    Diagnosis and treatment

    Fortunately, the first stage (gingivitis) is reversible, so long as a professional cleaning is performed and a home care program is instituted. The early stages of periodontal disease are characterized by gingivitis and halitosis (bad breath). Up to 80 percent of cats three years of age and older suffer from gingivitis. The signs of gingivitis include red, swollen, or bleeding gums; bad breath; finicky eating habits; and reluctance to eat hard food. Veterinarians must look for these red flags of gingivitis and begin professional cleaning when warranted.

    In cats, however, gingivitis can occur as young as 6 or 8 months, often associated with little or no calculus accumulation. We call this condition "juvenile-onset gingivitis." If left untreated, by 1 to 2 years of age, there may be irreversible periodontal disease. The exact cause of this condition is unknown, but genetics may play a role, since purebred cats, especially Siamese, Abyssinians, and Persians, are predisposed. Daily home care is essential in cats with this condition to avoid tooth loss. If not addressed promptly, gingivitis develops into periodontitis and advanced periodontal disease. Treatment of periodontal disease requires professional cleaning. This is done under general anesthesia. Most cases of advanced periodontal disease can be prevented if detected early and treated appropriately. By taking care of your cat's teeth, you're helping care for her overall health. Regular veterinary checkups and follow-up exams are necessary to maintain good dental health, especially if home dental care is not provided or tolerated by your cat.

    Tooth Resorption

    Tooth resorptions, formerly known as feline odontoclastic resorptive lesions (FORLs), are cavity-type erosions that develop in the teeth of some cats.

    Causes and symptoms

    FORLs are not caused by bacterial enzymes and decay and therefore are technically not cavities. Rather, they are the result of the cat's own body resorbing the teeth. In fact, the veterinary dental community now prefers the term tooth resorption rather than FORLs. Conceptually, however, it is easiest for us to think of them as cavities. They occur typically at the gumline or just below it. Tooth resorption is often classified according to the severity, with stage 1 being the mildest and stage 5 being the most destructive. Although there are several theories as to why some cats develop tooth resorption, the exact cause remains unknown. In the early stages, most affected cats do not show any clinical signs. As the erosion progresses into the pulp cavity of the tooth, the tooth becomes sensitive to heat, cold, and touch and becomes very painful. Affected cats may salivate and experience difficulty eating. Some cats may switch from eating hard food to soft food due to pain experienced from crunching on the hard food. With the pulp cavity exposed, bacteria in the mouth may infect the pulp cavity and travel to the apex of the tooth root, causing a tooth-root abscess.

    Diagnosis and treatment

    A diagnosis of tooth resorption is usually made upon visual inspection of the mouth during a routine veterinary visit. Touching the tooth with a cotton-swab at the site of a resorptive lesion often causes pain, evidenced by jaw spasm. Often, the gums will overgrow and cover the erosion in the tooth, giving the appearance of a red spot on the tooth. Dental radiographs confirm the diagnosis. Because tooth resorption can be progressive and painful to the cat, extraction of affected teeth is the recommended treatment. To date, there is no known proven method to prevent tooth resorption.

    Tooth Root Abscesses

    A tooth root abscess is an infection involving the root(s) of a tooth.

    Causes and symptoms

    Oral bacteria may enter the central pulp cavity of diseased or broken teeth and migrate to the root of the tooth, where they can cause infection. A pocket of pus develops at the root of the tooth. The abscessed tooth root is painful and uncomfortable for the cat. A swelling may develop on the cat's face near the infected root.

    Diagnosis and treatment

    Treatment of these abscesses requires drainage of the accumulated pus, followed by antibiotic treatment. Antibiotic therapy alone is rarely effective for these abscesses because the infection is trapped inside the tooth root. Drainage is best achieved through extraction of the affected tooth. Sometimes the abscess is so severe that the trapped bacteria tunnel a hole through the skin of the face to allow drainage. Once the tooth is removed, the gums will heal and the cat's mouth will no longer be painful.

    Veterinarian extracting a tooth from a cat.

    Lymphocytic/Plasmacytic Gingivitis and Stomatitis

    Lymphocytic/plasmacytic gingivitis and stomatitis (LPGS) is a painful inflammatory condition that causes a great deal of discomfort to many cats.

    Causes and symptoms

    Cats with LPGS exhibit chronic, severe inflammation and ulceration of the gums, back of the throat, and often other structures inside the mouth. The exact cause of LPGS is unknown, but it is most likely a combination of various factors. One theory is that some cats' gums are hypersensitive to bacterial plaque. Small amounts of plaque will cause the immune system to overreact and mount an exuberant inflammatory response, sending large numbers of inflammatory cells, mainly lymphocytes and plasma cells (hence the description "lymphocytic/plasmacytic"), into the gums and oral tissues. Suppression of the immune system has also been theorized as a cause or contributing factor in LPGS. Infection with FeLV and/or FIV is known to suppress the feline immune system and may play a role in some affected cats, although many other factors including stress and other environmental influences can weaken a cat's defenses and predispose her to illness. Other infectious causes have been implicated, including feline calicivirus. Some veterinarians feel that infection with the bacterial organism Bartonella may play a role in the disease, but this remains controversial. It has been suggested that a genetic predisposition is likely in some breeds.

    Oral pain is probably the most common sign of LPGS. This can manifest in a variety of ways. Cats may have difficulty eating or may stop eating entirely. Some will drool excessively, with the drool being blood tinged on occasion. Some cats approach the food dish as if they're interested in food (which they usually are), but then run from the food dish because eating is painful. A few cats will paw at their mouths and may develop an aversion to having their faces touched. Some cats stop eating their dry food, which can be painful to chew, and will only eat canned food. (This is often misinterpreted as being "finicky.") Cats tend to be relatively secretive about their illnesses and may manifest their oral discomfort in more subtle behavioral ways, such as being reclusive, irritable, or aggressive. Grooming may become uncomfortable, and cats may develop an unkempt hair coat as a result. Often, cats with LPGS have halitosis (bad breath).

    Diagnosis and treatment

    A definitive diagnosis of LPGS is achieved by biopsy of the affected tissues, although a presumptive diagnosis is often made based on the results of a thorough oral examination. General findings include extremely red, proliferative (swollen and overgrown), and ulcerated oral tissue that bleeds easily when touched. The most frequently affected tissues are the gums, although other areas of the mouth are commonly affected, such as the roof of the mouth, the fauces (the lateral walls at the back of the throat that surround the tonsils), the tongue, and sometimes the lips. Various degrees of dental and periodontal disease may be present because this often contributes to the severity of LPGS. Oral x-rays may reveal the presence of retained tooth roots and resorptive lesions-painful tooth erosions similar to cavities. In most cases, the cat needs to be sedated for a proper, thorough oral examination to be performed; general anesthesia is usually required if dental radiographs are to be taken.

    The goal of treatment is to decrease the inflammatory response. Control of plaque and tartar is the cornerstone of therapy, and therefore a thorough dental scaling and polishing should be performed. Ideally, cats' teeth should be brushed regularly after the dental scaling; however, cats with LPGS have mouths that may be too painful to tolerate brushing. Oral rinses or gels may be of benefit, but again, many cats find any manipulation of their mouths intolerable. Unfortunately, even with thorough dental scaling and subsequent home care, the condition often progresses. Antibiotics may help some cats during flare-ups of oral pain. Many cats need an occasional short course of antiinflammatory drugs during flare-ups. Ideally, the anti-inflammatory medication is given at initially high doses to control the inflammation, and then the dosage is tapered to the lowest dose that keeps the condition under control. However, as stated earlier, most cats won't allow oral administration of medication. In these cases, an injection of a longacting steroid is often the only alternative. The use of antibiotics and anti-inflammatory drugs, however, offers only a short-term "fix." Eventually, most cats become nonresponsive to medical treatment and will require extraction of all of the teeth except the canines (the "fangs"). In most cases, extraction alone successfully reduces the inflammation and allows the cat to eat and live normally. Cat owners often worry that their cat won't be able to eat after full-mouth extraction. Most cats, however, tolerate extractions very well and can eat moist food readily, Biblewith many cats able to crunch on dry food after the extraction sites have fully healed.Cats with LPGS are likely facing a lifetime of frequent veterinary visits and treatments. With vigilant monitoring and conscientious veterinary care, cats with LPGS can live comfortable happy lives.

    Regular veterinary checkups and follow-up exams are necessary to maintain good dental health.


    Cats show that they're happy in a variety of ways. They will purr, knead their paws, and sometimes offer up a couple of head butts. Occasionally, cats who are really on cloud nine will drool on their owners. If you are not doing something to make your cat super-happy, however, drooling is more likely to be a sign that something is amiss. Saliva is continuously produced by the salivary glands. Excessive production and secretion of saliva is called ptyalism. Oral problems and nervous system disorders are common reasons for ptyalism and subsequent drooling. Ptyalism should not be confused with pseudoptyalism, in which a normal amount of saliva is being produced and overflows from the mouth due to anatomic abnormalities such as malocclusion (abnormal alignment of the teeth) or to an inability or reluctance to swallow because of pain associated with swallowing.

    Disorders of the teeth and gums are the most common reason for drooling. Periodontal disease and the accompanying gingivitis, if severe, can lead to halitosis (bad breath), dysphagia (difficulty eating), and drooling. The initial step in determining the cause of a cat's drooling is a thorough oral examination. This may require sedation, tranquilization, or even general anesthesia because cats with painful mouths are often head shy and won't allow a comprehensive exam. During the oral exam, your veterinarian will check to see if your cat can close her mouth properly. Some cats cannot, due to malocclusion. Although congenital and developmental disorders are common causes of malocclusion, oral tumors can cause misalignment of the teeth and/or jaw leading to improper closing of the mouth and subsequent drooling.

    Paw and Nail Injuries and Problems

    Paw and Nail Injuries and Problems

    Cats claws are made of the protein keratin. Beneath the claw is a pink structure, the quick, which contains blood vessels, nerves, and cells that give rise to the keratin that makes the nail. Cats use their claws for climbing, for defense, and for killing prey. Like any part of the body, the feet are susceptible to injuries and illnesses.

    Paw Injuries and Diseases

    Your cat's paws serve a greater purpose than just standing and walking. Cats use their paws for predation, for territorial marking (via secretions from glands located on the pads), and for regulating body temperature through sweating. Like any part of the body, paws are susceptible to injury and illnesses.

    Eosinophilic Granuloma

    Eosinophilic granulomas are inflammatory lesions that commonly affect feline skin, including the lips and occasionally inside the mouth. This condition can also present as ulcerative lesions around the edges of the foot pads, often on several feet. It tends to occur in young cats (most affected cats being less than one year of age.) In most cases, it does not affect the cat's ability to walk; however, because the feet come into contact with dirty surfaces like the floor and the litter box, the ulcerated areas are susceptible to infection. Treatment with antibiotics can control infection, but anti-inflammatory medications must also be given so that the lesions resolve.


    Pemphigus foliaceus (PF) is a skin disorder in which blisters and pustules develop on the skin, affecting primarily the face, feet, and ears. It is more common in middle-aged and older cats. PF is an autoimmune disorder, a disorder in which the cat's immune system attacks a specific component of its own body-in this case, the skin. This causes the outermost layer of the skin to separate from the layers below, forming blisters or pustules. Although the face and ears are initially affected, the feet usually become affected, including the footpads. Eventually, the entire body becomes involved. Biopsy of the affected skin is usually required to make a definitive diagnosis. Treatment with antiinflammatory medications often brings the disorder under control; however, the drugs must be given for the remainder of the cat's life.

    Plasma Cell Pododermatitis

    Feline plasma cell pododermatitis is an uncommon disorder characterized by soft, usually painless swelling of several of the foot pads. In some cases, ulcers may develop on the swollen pads and may lead to secondary infection and pain. A tentative diagnosis is made on physical examination, due to the characteristic swollen, puffy appearance of the main weight-bearing pads (leading to the nickname "pillow paw" disease). Definitive diagnosis requires biopsy of an affected pad. The cause of the disorder is unknown, although the response to immunosuppressive medications suggests an autoimmune disorder (i.e., one in which the immune system inappropriately sends inflammatory cells into the pads).

    Nail Injuries and Problems

    Toenail injuries in cats are relatively common; however, they are usually of minor significance. The most commonly seen disorders of the nails in cats are broken nails and overgrown nails.

    Broken Nails

    Broken nails are a common problem in cats; if not removed promptly, they can result in pain and infection.

    Causes and symptoms

    Cats can get their claws stuck in a carpet or something similar, and when they pull their feet loose, they can tear a nail. Sometimes the tail is torn completely off. In most cases, the nail is partially torn and is dangling, causing pain every time the nail is moved. A partial or total avulsion of the nail will expose the underlying tissue, which is called the quick. The quick contains many nerve endings and is very sensitive. Cats may limp on the foot or refuse to bear any weight on it at all.

    Diagnosis and treatment

    Torn nails should be evaluated by a veterinarian. If the nail is partially torn, your veterinarian will remove the dangling nail. The exposed quick, besides being sensitive, is also at risk of becoming infected since cats scratch around in their litter boxes, which contain many bacteria. Your veterinarian will prescribe antibiotics and possibly pain medication. Switching to a new type of litter, such as shredded or pelleted newspaper, may help minimize the chance of infection. A new nail will regrow from the exposed quick over the course of a few weeks. Keeping the nails trimmed will prevent torn nails from occurring.

    Keeping your cat's claws trimmed will prevent her from getting them stuck in something and possibly pulling out the nail.

    Overgrown Nails

    If a cat's nails are not trimmed regularly, they can grow too long and inflict injuries.

    Causes and symptoms

    Normally, when cats groom their feet, they remove the outer nail sheath with their teeth. They also remove their outer nail sheaths when they use their scratching posts. If these sheaths don't get removed, they can grow too long, curling all the way around and piercing the pad of the affected toe.

    Diagnosis and treatment

    If the nail pierces the pad, your veterinarian will have to trim the nail and treat the wound that it created. If the wound is infected, antibiotics will be prescribed. In some cases, soaking the foot in an antiseptic solution may be beneficial. Overgrown nails can be prevented by keeping your cat's nails trimmed. If you cannot trim your cat's nails yourself, take your cat to your veterinarian or a groomer to have it done regularly, approximately every six to eight weeks.



    Normally, a cat has eighteen digits. The front paw has five toes: four toes and one dewclaw (the small toe on the medial side of the foot that doesn't touch the ground). The normal rear paw has four toes. Polydactylism (from the Greek: poly = "many," daktulos = "fingers") is the anatomical abnormality of having more than the usual number of digits on the paws. It is a natural genetic variation that occurs in many animals (as well as in humans), and it is a common trait among cats. Polydactyl cats are occasionally referred to as "mitten cats," "thumb cats," and "Hemingway cats," the latter name referring to the writer Ernest Hemingway. In the 1930s, Hemingway established a home on the small island of Key West, Florida, which he eventually shared with several cats, including a six-toed polydactyl named Snowball. Today, Hemingway's home has gone to the cats-some fifty of them-at least half of them polydactyls, all descendants of Snowball. Many other six-toed cats can be found elsewhere on the island as well

    Most polydactyl cats have one or two extra toes on each foot, with the extra toes appearing on the thumb side of the foot. Most cases of polydactylism affect the front feet only. The hind feet are less often affected. When they are, it is usually in addition to having polydactyl front feet. It is quite rare to find a cat with polydactyl rear paws and normal front paws. The gene for polydactylism can give rise to either extra toes or extra dewclaws. When polydactylism occurs on the hind paws it tends to cause extra toes rather than a dewclaw. Genetically, polydactylism is a simple autosomal (not related to gender) dominant trait. Cats with extra toes have the dominant gene. A cat needs only one copy of this gene from either parent to have the trait. If one parent has it, 40–50 percent of the kittens will have it, too. Because many polydactyl cats carry the gene for normal toes, the trait is never "fixed." In other words, even breeding two polydactyls doesn't guarantee all the kittens will be polydactyl. There will always be a few normal-toed kittens in the litter because of the recessive gene. Polydactylism doesn't affect cats adversely. It offers them no advantages, nor does it yield any disadvantages. It is an anomaly-a deviation from the norm-rather than a deformity, and most cat owners regard it as an enchanting quirk. The toenails associated with the extra toes tend to be normal nails, although occasionally, the extra toe is incompletely formed, and the nail bed is deformed, leading to claw problems like ingrown or overgrown claws. The extra nails of polydactyl cats, like all nails, require regular trimming.

    Normal, healthy cat's paw. Toepads on the same foot may be different colors.

    From The Cat Bible, Copyright by Sandy Robins, licensed through ContentOro, Inc and used by arrangement with I-5 Press

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