Feline allergic dermatitis (also known as feline hypersensitivity dermatitides) is characterized by an inflammatory response that causes chronic and recurrent pruritus.1,2 It is very similar to atopic dermatitis in dogs, but more is known about the pathogenesis of canine atopic dermatitis and the clinical signs are more distinct.3
The exact incidence of feline allergic dermatitis is not known. It is however, one of the most common reasons for cats to visit the vet.4 Twelve percent of all veterinary consultations are for dermatological problems and of these, 34% are for pruritus or alopecia.5 There is no recognized breed predisposition,1,2 however a genetic component is possible.3
Clinical signs of feline allergic skin disease usually occur before 2 years of age, but it is not uncommon for signs to appear later. It is also very common for cats to be first presented to a veterinarian after 2 years of age, as pet owners may miss the initial signs. Cats with allergic dermatitis are pruritic, but unlike dogs it can be hard to tell when a cat is itching. Pruritus is seen in cats as frequent grooming, licking, chewing, biting and sometimes scratching. Cats can be secretive and find a quiet place to lick and groom. Many owners can find it difficult to identify that their cat is showing signs of pruritus rather than normal grooming behavior.
Other signs of itching include vomiting fur, passing fur in feces or finding fur around the teeth. If the remaining hair is examined closely you may see that it is rough, due to the ends of the hair shafts being bitten off. This is known as 'barbering'.
Cats with allergic skin disease tend to show one or more of four patterns of lesion distribution. These patterns are not unique to allergic dermatitis caused by environmental allergens, but can be seen with other skin diseases, for example flea and food allergy.
References: 1. Scott-Muller and Kirk 6th ed (2001);580-581. 2. Favrot C et al. Vet Dermatol (2011);23:45-50. 3. Favrot C. J Feline Med Surg (2013);15:778-784. 4. Health News Digest, 22 May 2007. 5. Hill PB et al. Vet Record 2006;158:533-539.