According to The National Institute of Allergy and Infectious Diseases, between 6 and 10 million Americans are allergic to cats or other pets. If you're an allergy sufferer who also happens to be a cat lover, you may be interested in low allergen cats. But what makes a cat hypoallergenic? Low allergen, or "hypoallergenic" cats are those that typically produce fewer allergens than "regular" cats. The operative word here is "fewer." Hypoallergenic is not synonymous with non-allergenic, and no breed is completely non-allergenic.
A protein (Fel D1) is the allergen in the cat's saliva is what causes problems for allergy sufferers. Once your cat licks her coat, the allergen-laden spit dries and becomes airborne, seeking a warm home in your nose and sinuses. Some cat breeds produce less of this protein than others, making them hypoallergenic.