The researchers examined dust samples from 173 homes with 60 different breeds of dogs, including 11 breeds considered hypoallergenic. Samples were collected from the floor or carpet of the baby's bedroom one month after a newborn was brought home, and only from homes with just one dog. Researchers then analyzed the dust samples for the dog allergen Can f 1. There were no significant differences in allergen levels between homes with hypoallergenic dogs and those with other dogs.
Christine Cole Johnson, chair of the Henry Ford Detroit Hospital's public health sciences department stated:
"Based on previous allergy studies conducted here at Henry Ford, exposure to a dog early in life provides protection against dog allergy development. But the idea that you can buy a certain breed of dog and think it will cause less allergy problems for a person already dog-allergic is not borne out by our study."
While the sample size did not allow the researchers to test specific breeds, they said parents should not choose a pet based on hypoallergenic classifications. It is not even clear how a hypoallergenic breed earns the title. There is no single "official" list of them. Various breeds, often dogs that shed little hair, appear on lists posted on the Internet, and the American Kennel Club suggests 11 "hypoallergenic canine candidates," including poodles, soft-coated wheaten terriers, schnauzers and the Portuguese water dog, made famous two years ago when the Obama family adopted one.
"I have no idea where this whole concept came from. It's been around for a long time, and maybe people associated it with shedding. I think it's just a legend. You can't be assured that some breed is going to produce less allergen than another. Allergists, based on their experience, really think that it's just individual dogs that have some variations based on genetics or behavior, which produce more allergens than others. But it's not going to be a breed classification that predicts that."
Nearly half of U.S. households have a dog or cat. An estimated 10% of the population may be allergic to animals. A higher rate of 20 to 30% of individuals with asthma have pet allergy symptoms.
Pets can cause problems to allergic patients in several ways. Their dander, or skin flakes, as well as their saliva and urine, can cause an allergic reaction. The animal hair is not considered to be a very significant allergen. However, the hair or fur can collect pollen, dust, mold and other allergens.
Those pets that are known to cause significant allergic reactions should be removed from the home of the allergic patient to avoid possible progression of symptoms. A "trial" removal of a pet for a few days or even weeks may be of little value since an average of 20 weeks is required for allergen levels to reach levels found in homes without pets.
Sources: Veterinary Dermatology and The Allergist Online