Cat allergies are caused by the proteins found in the dander, saliva, blood and urine of cats.

Dander (tiny flakes of dead skin) is continually shed by animals. Proteins that are secreted by oil glands in the cat’s skin are also attached to this dander. Since cats are constantly shedding dander, allergens are deposited around any area in which the animal is present. Dander and dried saliva are also carried by air currents, even into areas the cat has not been (e.g., air ducts, walls). The proteins in dried urine tend to stay indoors because many cats use indoor litter boxes. In contained areas, such as a home, the overall accumulation of dander, urine, blood and saliva proteins is often enough to trigger an allergic reaction in people with cat allergies.

Saliva, urine, blood and dander allergens are present in all cats, even breeds labeled as non-allergenic. There is no such animal as a hypo-allergenic cat. Regardless of breed, size and hair, all cats may cause allergic reactions. Hairless cats have dander and release that dander by grooming themselves as often as haired cats. However, male cats may produce more of the proteins that trigger allergic reactions than females or neutered male cats.