Skin allergies, often called “atopy” or “atopic dermatitis,” are predispositions to becoming allergic to normally innocuous substances. Atopic dermatitis is classically characterized by severe pruritis (itchiness) and is triggered by inhalation or absorption of the allergen through the skin. Atopy is much less common in cats than in dogs, but it certainly does occur in cats.
Types of Skin Allergies in Cats
Skin allergies in cats can be mild, moderate or severe and can be caused by exposure to a number of different allergens.
Pollens and other components of grasses, weeds, trees and bushes are common environmental allergens causing skin allergies in cats. Indoor or outdoor mold spores, household dust mites, drugs, chemicals and animal dander are other common triggers of feline atopy.
One of the most common types of skin allergy in cats is hypersensitivity to external parasites, including fleas, mosquitoes, ear mites and/or ticks. Cats that are allergic to these parasites develop an immune-mediated hypersensitivity to the saliva from their bites that causes raised bumps, intense itching, vigorous scratching to the point of self-trauma and often nasty skin sores. Once exposure to the parasite is eliminated, the skin symptoms typically resolve.
Food allergies technically are not classified as atopy but definitely can cause adverse skin reactions, as well as periodic vomiting and diarrhea, in cats.
Feline miliary dermatitis, sometimes called “scabby cat disease,” is a particular crusting skin disorder that occurs predominantly on the cat’s back and usually is accompanied by varying degrees of itchiness. It can be caused by ectoparasites, hypersensitivity to food, drugs or chemicals, and fungal or bacterial infection. Other suggested causes of feline military dermatitis are malnutrition, hormonal disturbances and possibly underlying systemic medical conditions.