If you are thinking about adopting a dog and someone in your household suffers from pet allergies, you may have been told that certain breeds, including the Portuguese water dog made famous when it was adopted by the Obamas, are less likely to cause symptoms. But this is likely a myth, a recent study suggests.

In the study, owners of poodles, schnauzers, and even Portuguese water dogs, widely promoted as hypoallergenic, have the same amount of a dog allergen known as “Can f 1” in their homes as owners of dogs not typically billed as hypoallergenic.

The study is published online in the American Journal of Rhinology and Allergy. Researchers collected dust samples from 173 homes taken one month after a newborn was brought home. The samples were collected from the carpet or floor in the baby’s bedroom. Data were analyzed from homes with one dog only. The study included 60 dog breeds, 11 of which are often promoted as hypoallergenic. The researchers found that 94.2% of homes showed detectable levels of the allergen, and there were no significant differences between breeds.

Dr. Kenneth Backman of Allergy & Asthma Care of Fairfield County points out: “We’ve known for years that dog breeds labeled ‘hypoallergenic’ had never been proven to be so. This label has typically been given by breeders to dogs that don’t shed. However, since the allergen comes from the saliva and dander, which all dogs have, even hypoallergenic dogs can unfortunately cause allergy symptoms.”