As in the human population, the incidence of allergies in pets seems to be increasing. While allergic
humans may often sneeze, wheeze or even have serious respiratory difficulties, allergic reactions in
pets are characterized by skin problems, exacerbated by their primary symptom—itching and
scratching. Cat and dog allergies fall into three main categories: flea allergy dermatitis, atopy, and
food allergy. Many pets can be affected by one or more allergy.