Hypoallergenic dogs not allergen free as claimed: Study

By Dr. Ananya Mandal, MDJul 13 2011

New research shows that the levels of dog allergens don't appear to be very different in houses with hypoallergenic dogs than in those with other dogs.

In this study, unlike previous studies, researchers didn’t inspect dander directly from dog hair. Charlotte Nicholas of Henry Ford Health System and her colleagues turned to the Wayne County Health, Environment, Allergy, and Asthma Longitudinal Study (WHEALS), in which urban and suburban Detroit women were recruited during a second or third trimester prenatal visit.

They measured allergen levels in the carpets or floors of 173 households with one newborn baby—and one dog. A month after the baby came home researchers collected dust samples from the baby’s room and measured levels of a common dog allergen, Canis familiaris.

Results showed that there was no significant difference in the allergen levels between households with hypoallergenic dogs and other dogs, even after taking into account factors such as whether the dog was allowed in the baby’s room, the dog’s size or how long the dog had lived in the house. The results of the small study were published online in the July/August volume of the American Journal of Rhinology and Allergy.

The authors write, “Clinicians should advise patients that they cannot rely on breeds deemed to be “hypoallergenic” to in fact disperse less allergen in their environment. Additional scientific investigation into dog-specific factors and whether hypoallergenic breeds truly exist is warranted.” The study's author, Dr. Christine Johnson, chair of Henry Ford's Department of Public Health Sciences, said, “We found no scientific basis to the claim hypoallergenic dogs have less allergen.”

The authors acknowledged some limitations of the study, including the lack of information on the amount of time the dog spent in the baby's bedroom, the reliance on maternal report of the dog breed, and a sample size that was too small to conduct analyses of individual breeds. In addition, they wrote, “collecting samples directly from the dog as opposed to from the floor of the baby's bedroom may have made our results more similar to the few in the literature; however, the goal was not to replicate these laboratory studies, but rather to learn if certain breeds of dogs were associated with lower levels of dog allergen in the home.”