Cats can have allergies just like humans. Unlike allergies in people, though, a cat suffering from inhaled or ingested allergies will exhibit signs of itching, including scratching, chewing, and biting. One such allergic condition is called feline atopic dermatitis.
What Is Feline Atopic Dermatitis?
Feline atopic dermatitis, sometimes called feline atopy or non-flea, non-food allergic dermatitis, is a common allergic condition seen in cats. In fact, feline atopic dermatitis is the second most commonly-diagnosed allergy in cats, behind flea allergy dermatitis. Feline atopic dermatitis occurs when they are exposed to an allergen, such as pollen, mold spores, and dust particles or even elements causing food reactions. Allergens can be inhaled or ingested. Feline atopic dermatitis may be seasonal or non-seasonal with many cats being diagnosed in early adulthood as this is when most allergies develop for cats.
Symptoms of Feline Atopic Dermatitis
A cat suffering from feline atopic dermatitis may chew, lick, or scratch all over. Generally, though, the paws, face, ears, axilla (or armpit areas), and the front of the legs are most affected. This is in contrast to the aforementioned flea allergy dermatitis, which causes cats to chew and lick their tail, rump, groin, and thigh area. Of course, it's entirely possible for a cat with feline atopic dermatitis to also suffer from flea allergy dermatitis, so you may see scabby spots and hair loss in both areas.
Unfortunately, as with allergies in people, we don't fully understand why cats get allergies. We can determine what they are allergic to, though, and that can actually help with treatment.
Treatment & Prevention
The first step in treating feline atopic dermatitis is to treat your cat's immediate skin infections. These infections are secondary to their scratching and biting. Your vet will want to take some cytology samples, most often obtained simply by rubbing a piece of scotch tape over a lesion, to determine if a crusty spot has an bacteria, yeast, or both. Bacterial skin infections are then treated with antibiotics while fungal infections are treated with antifungal medications.
To help to immediately relieve your cat's itching, your vet may recommend steroids. Corticosteroids can be very effective in keeping itching and inflammation at bay, but they aren't without their drawbacks. They have side effects with both short-term and long-term usage. They can cause your cat to experience an increase in appetite, thirst, and urination short term, so you may find yourself cleaning out the litter box more regularly and your cat may beg for food more often. Long-term use can lead to sequelae's like diabetes and affect the immune system. Your vet can help determine if corticosteroids are appropriate for your cat. They can also help you find the lowest effective dose of corticosteroid for your cat and will want to monitor your cat's bloodwork to check for any changes in organ function.
The most effective long-term treatment of feline atopic dermatitis involves determining what your cat is allergic to. Your vet may first want you to start with a food trial which involves putting your cat on a prescription, hydrolyzed diet, which helps to determine which protein your cat is allergic to (as cats are more likely to be allergic to proteins versus grains). Hydrolyzed is just a fancy way to say that the protein source is broken down into its individual amino acids, so your cat's immune system won't be able to tell if the protein is poultry, beef, or fish. Your cat will need to be fed this diet exclusively for 8 to 12 weeks as you wait to see if their symptoms resolve. This means no other foods or treats. If your cat's symptoms resolve while they are on the prescription food, their allergies are most likely due to a food allergy. If it's determined that your cat has a food allergy, it is recommended to keep them on the hydrolyzed food for life to prevent allergy flare ups.
Some cats will need to have testing done by a veterinary dermatologist. Often they will do an intradermal testing and even blood testing to help determine what allergens are affecting your cat. Once it is determined what in your environment your cat is allergic to, the lab can create immunotherapy drops that you can give to your cat orally to help build up their immune system. Many cat's will need to go on long term medications to help prevent flare ups such as cyclosporine but your veterinarian will discuss their recommendations based on how your cat is doing.
Unfortunately, there no current prevention for the development of feline atopic dermatitis. Recognizing the symptoms and keeping up with your cat's flare ups, though, can help keep your cat as comfortable as possible when their allergies are bothering them.