Cat Dermatitis

Introduction

Dermatitis is defined as any inflammation of the skin. It can manifest in a number of ways and is one of the most frustrating conditions for owners of companion cats. In many cases, the cause of dermatitis is never discovered; in other cases, it takes prolonged diagnostic work to identify the causative agent.

How Dermatitis Affects Cats

The clinical signs of feline dermatitis usually involve chronic and sometimes frantic scratching, itching, pawing and rubbing of affected areas – commonly the paws, face, underarm area and base of the tail - which may or may not fluctuate seasonally. Their skin typically becomes inflamed and irritated from the underlying irritant, self-trauma or both. Another common sign is hair loss due to damage to the hair follicles. "Hot spots" can develop, along with ulceration, raised red eruptions or other sores. The cat's skin may become oily or dry and scaly, and is often accompanied by ear infections and a foul smell. Feline dermatitis tends to be progressive, regardless of its cause, unless it is treated appropriately.

Causes & Prevention

Causes of Dermatitis in Cats

The causes of feline dermatitis are elusive and can vary widely. They can include contact with irritating animal, vegetable or chemical substances, exposure to extreme temperature conditions, mechanical irritation, self-trauma, malnutrition, immune-mediated disorders and viral, bacterial, fungal or other infectious disease. Allergic reactions to external parasitic bites (fleas, ticks, mites, lice) or to certain foods, grasses, detergents, plants or other environmental allergens, are among the most common causes of dermatitis in cats. Incidents of dermatophytosis (a non-parasitic fungal disease affecting the hair, nails and skin, commonly called "ringworm") tend to be higher in cats than in dogs and probably are underdiagnosed in cats as a cause of dermatitis. Sometimes, the underlying cause will never be discovered. In those cases, prescription oral and topical medications may be helpful to soothe the cat's symptoms. If not treated, feline dermatitis can predispose affected animals to secondary bacterial skin infections, or worse.

Preventing Dermatitis in Cats

Prevention of dermatitis depends upon the underlying cause of the condition. Many topical preventatives are available to minimize allergic reactions to or infection by external parasites. In addition, all companion cats should be fed a high-quality, balanced diet. Medicated shampoos and other lotions or salves often are helpful to moisturize and soothe skin affected by dermatitis and to relieve the accompanying itchiness.

Special Notes

Successful treatment of feline dermatitis requires identifying the source of the condition through a number of available veterinary diagnostic techniques and then eliminating or removing the source once it is identified. As long as the cause can be addressed, the outlook for cats with dermatitis is fairly good to excellent. Dermatitis caused by a systemic disease or condition (such as one contributing to immunodeficiency) typically will not resolve unless that condition can be treated successfully. Dermatophytosis caused by Microsporum canis (cats and dogs are the normal hosts) is a zoonotic disease, making humans at risk of infection if they are exposed to an infected cat.

Symptoms & Signs

Dermatitis in cats is a condition in which the skin becomes inflamed and irritated. This is a particularly frustrating condition in cats because it can be caused by a number of different sources. Allergies to parasitic bites, certain types of foods, grasses, detergents, or plants are some of the leading causes of dermatitis in cats; many other cats suffering from dermatitis experience this condition from exposure or reaction to a fungus, or as a result of high temperatures and humidity. Whatever the cause, dermatitis can cause symptoms that range from mildly irritating to severely painful.

Symptoms of Dermatitis in Cats

The symptoms of dermatitis in cats generally depend on what caused the dermatitis, and how severely the cat's skin reacted to the cause. Most pet owners notice that their cat begins to develop dermatitis symptoms in the spring and summer months. The beginning symptoms of dermatitis are often itchy and red skin. The cat may begin to scratch a lot more than usual, or perform various body rubs on the floor to ease itching sensations; the cat may also begin to lick the paws and the base of the tail a lot. Often the pet owner will notice that the areas around the groin, under the neck, and under the legs have become inflamed and irritated.

Advancing cases of dermatitis cause symptoms that are progressively worse. The skin will often become scaly or will have a lot of dandruff. Upon petting the cat the pet owner may notice small bits of skin that is coming off. Constant licking on the paws and base of the tail, or any other area of the body, can cause hot spots to occur; these are sores which develop, then become infected, and continue to worsen if the dermatitis is not treated. Sometimes small red bumps will be noticed all over the cat's body, and often dermatitis is accompanied by ear infections and a strong odor from the body and ears.
While the cause of the dermatitis can often be elusive, treatments to calm the symptoms should begin as soon as possible.

Diagnosis & Tests

Dermatitis in cats is an inflammatory, irritating, often pruritic (itchy) and painful condition that can be somewhat simple to diagnose but difficult to treat. Cats in particular seem prone to inflammatory skin reactions caused by parasites, bacteria, fungi and food or drug allergens. The general terms "feline miliary dermatitis" or "scabby cat disease" are sometimes used to describe this crusting and itchy skin condition in cats, which presumably is caused by some adverse reaction to an irritant. A number of tests are available to help veterinarians diagnose dermatitis generally, and hopefully to determine the cause of the condition specifically.

Diagnosing Feline Dermatitis

When a cat presents with signs of skin inflammation, the veterinarian will begin a search for the underlying cause of the condition. This diagnostic journey normally begins with a thorough history and physical examination, focusing on whether any outside factors (fleas or other external parasites, exposure to any potential environmental allergens, etc.) are easily identifiable as possible causes. Flea bites can cause horrible dermatitis in cats, and demodectic mange can also cause similar symptoms. Your veterinarian will examine your cat's hair coat to look for signs of external parasites and probably will perform a fecal analysis to check for internal parasites which might be causing or contributing to a weakened immune system. She may also do a skin scraping to help identify any parasites that have burroughed deep into the cat's hair follicles. Other initial tests usually include taking swabs of ear residue and examining them microscopically (to check for ear mites or other organisms), and in some cases a quick Wood's lamp test to see if the cat's skin has been infected with ringworm.
If no obvious cause of dermatitis is found, the search must go on. Blood tests can help to rule out systemic causes of dermatitis, such as immune disorders. If blood tests are normal, the veterinarian probably will focus on possible causes of hypersensitivity (allergic) reactions that could contribute to skin inflammation. Dietary changes may be recommended to rule in or out possible food allergies, and shampoos or other topical products may be considered as well.

If an external parasitic, bacterial or fungal infection is isolated, the cat will be treated appropriately with topical, oral or injectible medications to eliminate the causative irritants and calm and soothe the inflammatory skin reaction.
Sometimes, the underlying cause of feline dermatitis is never discovered, but certain prescription medications and shampoos still may help to reduce the severity of the symptoms. If left untreated, dermatitis can progress to secondary bacterial skin and possibly systemic infections. If your cat shows signs of dermatitis, make an appointment with your veterinarian as soon as possible.