Nov. 12, 2008 -- Hypoallergenic dogs have gotten a lot of buzz lately as the Obama family searches for a dog to bring with them to the White House -- without triggering dog allergies in older Obama daughter, Malia.
A quick glance at the Internet shows lots of web sites devoted to "hypoallergenic dogs" and "hypoallergenic dog breeds." But no dog may be free of potential allergens, cautions allergy and asthma expert Corinna Bowser, MD, of Havertown, Pa.
Is there such a thing as a hypoallergenic dog?
"I don't think there is such a thing as a hypoallergenic dog," Bowser tells WebMD.
She explains that the major allergen in dogs is a protein found in dog serum, and dogs excrete that allergen in sweat and shed it from their skin. "It also gets secreted into the saliva, and possibly a little bit in the urine," Bowser says.
Since all dogs have that protein, no dog is completely allergy-free, according to Bowser.
Karl Jandrey, DVM, an assistant professor at the University of California, Davis' School of Veterinary Medicine, agrees with Bowser. "There really is no truly allergy-free dog," Jandrey tells WebMD via email. But Jandrey also notes that "low-allergen" dog breeds may include poodle, bichon frise, and Maltese.
What about dog breeds?
Bowser says she didn't find much evidence in medical literature about dog breeds being better or worse for allergies.
But she did find a German study, published this year, that tracked allergies among people exposed to various dog breeds. "They said factors related to individual dogs seem to influence the allergenicity more than breed or gender, which I thought was interesting," says Bowser.
In other words, it was a dog-by-dog issue more than a breed-by-breed issue in that particular study, which Bowser says is the only one she found that involved specialized allergy tests.
Jandrey agrees that "some people who have been allergic to one dog may be less allergic to other dog breeds or individual [dogs] within the same breed."
Does the dog's size or hair length matter?
"The size of dog could matter in terms of the overall amount of allergen," with smaller dogs contributing less allergen, says Bowser.
"Hair length could have something to do with how it spreads in the house," Bowser says. She explains that shorter dog hairs may not stick as much as long hair to furniture, clothes, and other surfaces, "so maybe the allergen does not stick as much, but the amount of allergen should be the same."
What about dogs with no hair? "Hairless animals have a lower allergenicity but the dander from the skin can still pose a problem for anyone sensitive to it," Jandrey says.
So are all dogs off limits to the Obamas?
Bowser has no ties to the Obamas, but she says that "if this was my patient ... I would say it's probably better not to get a dog."
"Of course, now he [Obama] made the promise and he kind of has to," she says. So Bowser recommends doing two things before bringing a puppy home: Dog-sit and see how Malia's allergies fare, and set some rules about how they'll handle any allergy issues.
"What we tell our patients is draw an imaginary line in the sand. If the child has an ER visit for asthma or needs significantly more medication, or whatever you want to determine as the line, that's when the dog has to go. And set these rules ahead of time, because then everybody knows that's when the dog has to go," Bowser says.
What can a family do once they've brought a dog home?
Here are Bowser's tips:
- Keep the dog out of the allergic child's bedroom, since the child spends a lot of time there.
- Wash your hands after petting the dog.
- Keep the house clean.
- Consider using an air purifier.
Bowser speaks from experience. She's allergic to cats, but her husband had a cat when they married. So their cat is banned from their bedroom, and they use air filters; she washes her hands after petting the cat so that she doesn't rub her eyes and wind up with swollen, itchy eyes.
Bowser also mentions the "hygiene hypothesis," which holds that exposure to animals and less-than-sterile environments may reduce the risk of developing allergies.
Could a dog allergy fade?
Allergies to dogs and cats may shift over time, notes Bowser.
For instance, she says some patients who grew up with a dog develop symptoms of dog allergies after being away from home for a long time, such as college students returning home for the holidays. "They visit their parents for Thanksgiving ... and they have symptoms where they never had symptoms before," says Bowser.
"We know of certain allergens that are always bad for people with allergies. For example, the dust mite or cockroach -- they're always bad. But dog or cat are kind of in the gray zone," Bowser says, adding that she's getting used to her husband's cat. "That's my experience," she says. "I'm actually not really doing bad with this cat."