Introduction
Atopy, also known as allergic inhalant dermatitis and atopic dermatitis, is an immune-mediated inflammatory and pruritic allergic disease which affects the skin and respiratory system of cats. The symptoms of atopy normally begin between 6 and 36 months of age and generally worsen as the cat becomes older. Atopy also tends to worsen during the spring and summer months in the United States, although over time it can become chronically non-seasonal. The hallmark of feline and canine atopy is intense pruritus (itchiness). However, atopy is much less commonly diagnosed in cats and the characteristic signs in cats differ somewhat from those in dogs.
Symptoms of Atopy in Cats
There is no reported gender or breed predilection for atopy in cats. The most common clinical signs of feline atopy are intense itching, scratching, licking, biting, chewing and hair loss around the feet, face, ears, tail base and underbelly. In cats, atopy also tends to manifest with symmetric alopecia (hair loss), miliary dermatitis or one of several eosinophilic granuloma complex lesions (these are eosinophilic plaques, eosinophilic granulomas and indolent ulcers, the description of which is beyond the scope of this article). Self-trauma, sores and scabs followed by secondary bacterial or yeast infections occur, but less frequently in cats than in dogs. In addition to these cutaneous signs of pruritis, many atopic cats develop recurrent or chronic otitis (ear infections). Their ears can become swollen and inflamed, itchy and irritated, and in many cases develop a nasty odor accompanied by profuse amounts of ear wax. Atopic cats also tend to develop respiratory symptoms which mimic feline asthma. Most clinical signs of feline atopy worsen with time.
True immune-mediated atopy in cats cannot be “cured,” but it can be controlled with appropriate medical management and identification and removal of the inciting allergens.