According to a study by researchers at Henry Ford Hospital, hypoallergenic dogs produce just as much allergen as other dogs, suggesting that they're just as bad for people with dog allergies as other breeds are.

The origin and meaning of the term hypoallergenic dog is unclear. For several years, the American Kennel Club has suggested that 11 breeds of dog "generally do well with people with allergies." The AKC says that these breeds produce less dander but also mentions that there is no such thing as a truly hypoallergenic dog. Many people and organizations have come to call these 11 breeds hypoallergenic.

Exposure to a dog in early life does seem to prevent dog allergies from developing.

The breeds are: Bedlington Terrier, Bichon Frise, Chinese Crested, Irish Water Spaniel, Kerry Blue Terrier, Maltese, Poodle, Portuguese Water Dog, Schnauzer, Soft Coated Wheaten Terrier and Xoloitzcuintli.

But the Henry Ford study didn't find anything special about these breeds.

The study looked at dust samples from 173 single-dog homes, one month after a newborn was brought home. The dust samples came from the carpet or floor in the baby's bedroom and were analyzed for the dog allergen can f 1. This allergen is thought to be responsible for over half of all dog allergies. There were sixty different breeds of dogs in the study, including the 11 that are sometimes called hypoallergenic.

There was no significant difference in the amount of can f 1 produced by the hypoallergenic dogs and the non-hypoallergenic dogs. Even using different criteria for classing the dogs as hypoallergenic (purebred only, mixed breed only, one hypoallergenic parent, etc.), these dogs did not produce less can f 1.

The researchers acknowledge some limitations to their study. No record was kept of how much time the dog spent in the baby's bedroom. And the sample size was too small to compare individual breeds, just the so-called hypoallergenic breeds to non-hypoallergenic ones. But it's more thorough than previous studies, which looked at hair samples from only a handful of dogs.

The researchers do mention that other studies have shown that exposure to a dog in early life does seem to prevent dog allergies from developing. But they say their study offers no evidence that certain breeds of dogs will lessen allergy problems for anyone who is already allergic to dogs.

An article on the study is scheduled to be published online in July 2011 by American Journal of Rhinology & Allergy.