Exposing infants to dogs and cats does not seem to make them allergy-prone

THE QUESTION Does keeping a dog or cat in the home affect whether a child develops an allergy to the pet?

THIS STUDY involved 565 youths on whom data were collected from birth to age 18, when blood samples were drawn for allergy testing. At that point, 101 of them were allergic to dogs and 116 to cats. Teens who had lived with an indoor cat during their first year of life were about half as likely to be allergic to cats at age 18 as were teens who, during their first year, had not lived in the same house as a cat. For dogs, boys who had a dog living in the house until their first birthday were also half as likely, at age 18, to be allergic to dogs as other boys. No statistically significant effect was found for girls exposed to dogs at that age. Cumulative exposure from birth to age 18 to dogs or cats at home did not affect the likelihood that a child would become allergic, nor did exposure at any other specific age.

WHO MAY BE AFFECTED? Children who share a home with a dog or cat. Pet allergies usually are triggered by allergens carried on an animal’s dander, flakes of dead skin that it sheds. Proteins in the pet’s saliva are the main allergen. They get on the skin when the animal licks itself, the substance dries and eventually the skin flakes off. Common symptoms of a pet allergy are sneezing and a runny nose, although some people also have trouble breathing.

CAVEATS Data from the youths’ early years came from interviews with their mothers; some later information came from the teens’ answers on questionnaires. Although the researchers adjusted the data to reflect a family history of allergies, parents with severe pet allergies may have avoided having pets in the home. Why girls’ risk for developing a dog allergy was not affected by in-home exposure was not determined.

FIND THIS STUDY July issue of Clinical & Experimental Allergy.

LEARN MORE ABOUT pet allergies at and www.

— Linda Searing

The research described in Quick Study comes from credible, peer-reviewed journals. Nonetheless, conclusive evidence about a treatment's effectiveness is rarely found in a single study. Anyone considering changing or beginning treatment of any kind should consult with a physician.