"Up to 30% of people who are allergic to dogs are actually allergic to one specific protein that's made in the prostate of a dog," said Dr. Lakiea Wright, an allergist at Brigham and Women's Hospital in Boston.
While the protein was identified years ago, a reliable blood test for the allergen was only approved by the US Food and Drug Administration last May.
"If you're allergic to only that specific protein in the male dog, you may be able to tolerate a female or a neutered dog," Wright said.
How pet allergies work
Allergies to animals with fur are common, especially in people who have asthma or other allergies such as pollen or dust. Three in 10 people with any allergy will also be allergic to their cat or dog, according to the Asthma and Allergy Foundation of America.
It's not the hair of the animal that triggers the allergic reaction. It's proteins in the urine, saliva and dander (or dead skin cells), of the dog or cat that trigger an oversensitive immune system to react. To date, science has identified six specific dog allergens.
And here's where the good news comes in: People can be allergic to one or more of the five dog proteins but not others, which may affect which breed or gender will send you into a sneezing fit.
Spoiler: Because all dogs make one or more types of proteins, there truly is no such thing as a "hypoallergenic" dog, Wright said.
"When we suspect a dog allergy, we're testing for that whole allergen," Wright explained. "But then we're also looking at specific proteins, the parts that make up the whole, to refine that diagnoses."
In the male dog, a protein called Can f 5 is made in the prostate. When the dog urinates, the protein can spread to the skin and hair throughout the body.
"These proteins are very lightweight, so they get dispersed in the air as the animal moves around," Wright said, "They can also stay in the air for a long time and land on our furniture, mattress, even our clothes."
Because we carry those on our clothes, pet allergens can be found in homes and other places where a pet has never been.
How do you know if you're only allergic to male dogs?
Start by giving your allergy doctor a good history of your symptoms, Wright said. When did the symptoms begin? Do you find yourself sneezing only -- or more -- around male dogs?
Also, ask: How many other allergies do you have? Allergies tend to gang up. More than three specific types makes you especially vulnerable to developing asthma or other breathing issues, Wright said.
If your history indicates, doctors can test for a reaction to Can f 5 via a skin prick or blood test, which was approved not long ago by the US Food and Drug Administration.
If you're not allergic to Can f 5 but still have a reaction, you can also reduce your exposure to allergens and the symptoms they produce by taking the following steps recommended by the Asthma and Allergy Foundation of America:
- Change your clothes after you've been around any dogs or cats.
- Ask a family member without a pet allergy to clean litter boxes or bedding and brush the pet outside.
- Keep your pet out of the bedroom. And consider a HEPA air cleaner in there, but first clean aggressively -- pet allergens can hang around for months.
- Dog and cat allergens are "sticky" and can remain in wall-to-wall carpet. Remove it if possible, and scrub the walls and woodwork. "Bare floors and walls are best."
- Vacuums stir up any allergens that have settled, so wear a mask and use a vacuum with a certified filter. Also use a certified filter for central heat and air units.
- Be sure to visit a specialist to check out your allergies. They may be able to recommend medications or immunotherapy treatments.
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