Having an affectionate pet dog is one of life’s great pleasures. For me, watching Lassie on TV when I was a child was the canine gold standard. Seeing my middle daughter snuggle a Lassie dog at Universal Studios in LA when she was 10 years old was very special.
The end of this month marks 24 years, since completing fellowship training, that I have treated allergic conditions. One of the most difficult topics, especially since I started to hear the term ‘hypoallergenic dog’ around 2000, is advising a patient or parent of a child who is allergic to dogs. As allergists, we are supposed to heed the teachings of clinical scientists and say that there should be no dog in the home. That is easier said than done when the desire to have a dog is so compelling. When I hear multiple times every month that the patient has a hypoallergenic dog, or that there is a plan to buy a hypoallergenic dog, the science must be reconciled with what actually happens for each affected person.
Many web sites will tout that certain dog breeds are hypoallergenic. The American Kennel Club, a well-recognized and respected organization, listed in 2016 on their website a list of “the best dog breeds to own that don’t shed.” Among those considered to have hypoallergenic coats were the Bedlington Terrier, the Bichon Frise, the Kerry Blue Terrier, the Lagotto Romagnola, the Maltese, the Poodle and the Portuguese Water Dog. However, no significant references on this site or on other websites are given to support the hypoallergenic claims.
Meanwhile, the scientific literature does not support the existence of hypoallergenic dogs. There are just a few studies that compare hypoallergenic dog breeds to other breeds considered not to be hypoallergenic. The last such article was published in 2012 and compared four hypoallergenic breeds—labradoodle, poodle, Spanish water dog and Airedale terrier—to Labrador retriever and a control group of 47 different other nonhypoallergenic breeds and cross breeds. The data of measuring the major protein allergen in dog hair, dog coat, floor dust and airborne samples of homes showed (a) higher allergen levels were found in hair and coats of hypoallergenic breeds and (b) airborne levels were similar across different breeds. The results did not support the belief that hypoallergenic dogs produce less allergen.
Some features of the data pointed out by the authors of the paper, though, should be considered in the decision about the existence of hypoallergenic dogs. Owners reported fewer allergic symptoms to hypoallergenic dogs; the answers, however, may be the result of selective recall. Other dog allergens besides the major one Can f 1 may be relevant but no techniques to measure them in large studies were available. Another very important recognition is that “enormous” variability was seen between individual dogs of the same breed.
Medicine is both an art and a science. Some balance must be struck between rigorously controlled research findings and what each individual wants and observes with a specific dog. Since food allergy research in recent years establishes the concept of eliciting/threshold doses of a food and that this can vary between allergic individuals, then the same biological concept should apply for animal allergens. As long as the person is not in denial about his or her symptoms and the underlying allergic problems are not severe, having a smaller dog—which sheds less dander than larger dogs—would seem to be a rational choice for having a pet dog. The standard allergists’ recommendations still apply: no dog in the bedroom, no carpeting in the home, no personal cleaning or grooming of the dog, bathing the dog 1 or 2 times per week and using a HEPA air purifier.
Personalized medicine occurs when we apply general findings from studies to each person’s unique physiology and immune system. When that occurs in dog allergy treatment, all humans and dogs will live together—instead of their immune systems fighting like cats and dogs.