December 10th, 2018
he domestic house cat (Felis domesticus) is a small, furry, do-mesticated, carnivorous mammal that is valued for its companion-ship and for its ability to hunt rodents. Cats have been associated with humans for at least 9500 years and are currently the most popular pet in the world.1 Because of their close association with humans, cats are now found almost everywhere on Earth. Allergies to furry animals other than cats and dogs have been extensively reviewed elsewhere and are not the topic of this practice parame-ter.2,3
According to the American Pet Products Manufacturers Associ-ation survey from 2010, it is estimated that there are 93.6 million cat owners in the United States.4 The same survey shows that 33% of US households (or 38.2 million) own at least 1 cat, and 56% of those own more than 1 cat.
The dog (Canis lupus familiaris) is a domesticated form of the gray wolf. Members of the Canidae family of the order Carnivora, dogs are the most widely kept companion animals in human his-tory. The 2010 American Pet Products Manufacturers Association survey estimates that there are 77.5 million dog owners in the United States.4 The same survey shows that nearly 40% of American households own at least 1 dog, of which 67% own just 1 dog, 25%own 2 dogs, and nearly 9% own 3 or more dogs.
Both cats and dogs have a number of identified allergens with a variety of biologic and immunologic properties. These allergens are present throughout the indoor environment of homes, with ani-mals living in them and in other buildings, such as schools and workplaces, regardless of whether the animals are present. For that reason, some degree of exposure to cat and dog allergens is inevi-table. It is recommended that cats and dogs be removed from the environment or at least kept out of the bedroom to reduce exposure to these allergens. In addition, the length of hair does not corre-spond with the allergenicity of a cat or dog, and there is no evidence of the existence of a completely nonallergenic furry animal. Be-cause carpeting and bedding serve as significant reservoirs, fre-quent vacuuming or ideally carpet removal should be considered.
The health effects of furry animal exposure include develop-ment of allergen specific IgE (defined as sensitization) in suscepti-ble individuals, often leading to manifestations of diseases, such as asthma and rhinitis, if the exposure persists. Once a sensitized individual develops an allergic disease, continued exposure to the allergens is likely to exacerbate symptoms and lead to poorer out-comes. It is with this background in mind that identification of exposure sources and their removal can be used as a form of treat-ment.