Cat Allergy and Dog Allergy: A Gander at Dander

in Asthma, Features, Pets
Pet allergies are caused by proteins in the dander, saliva, and sebum of pets.Photo: Getty

The doctor’s advice sounds clear enough – if you have pet allergies that make you wheeze and sneeze, stay away. But anyone with allergies knows life isn’t always so simple.

Some people whose eyes are aflame after five minutes near a sheepdog can live with a poodle without ever cracking a tissue box. Others find that regularly bathing a pet greatly reduces allergic symptoms. But yet an unlucky few can react to dander inside a house where a cat hasn’t lived for years.

Who Reacts

Even our understanding of the prevalence of pet allergies is fuzzy. Although an estimated 20 to 30 percent of young adults will react to at least one airborne allergen, studies have shown early exposure to animals (which researchers now suggest can have a protective effect), where you live, and whether you experience asthma, hay fever or both can all influence the development of pet allergies.

Research from the U.S. National Institutes of Health shows that cats are the single biggest trigger for asthma, causing reactions in 29.3 percent of asthmatics. A Swedish study, meantime, found 40 percent of kids with asthma reacted to cats, 34 percent to dogs, and 28 percent to horses.

For the kids who got runny noses and itchy eyes, 49 percent reacted to cats, 33 percent to dogs, and 37 percent to horses.

Dr. Jeffrey Davidson, an allergist in San Francisco and a clinical professor at the University of California San Francisco, says it’s fair to expect that as the incidence of allergic disease grows, so does the number of people reacting to animals. And while cat allergies are by far the most prevalent, people can be sensitized to any animals with feathers and fur, including dogs, guinea pigs, mice, birds, and ferrets.

The Symptoms of Pet Allergies

The range and severity of symptoms is vast, and includes itchy, runny nose and sneezing, irritated, watering eyes, wheezing and shortness of breath, eczema and hives. “Some people say they don’t have a problem unless they touch the pet and touch their eyes,” Davidson said. “And there are other people who walk into a room where there is a cat, or there has been one, and they will have an asthma attack.”

The Allergens

The culprits setting of these reactions are a series of proteins found in concentrated amounts in dander (flakes of dead skin), saliva and oil called sebum that hair follicles secrete to protect fur and skin. In some animals, allergenic proteins that originate in the blood are released through urine. The cat’s most prominent allergenic protein is called Fel d1, and its counterpart in dogs is Can f1.

Dr. James Ransom, an allergist in Topeka, Kansas and clinical instructor at The University of Kansas Medical Center, says cats’ constant grooming and indoor litter boxes mean these allergens are continuously evaporating into indoor air. A pet lover might reason a hairless cat or a short-haired dog should be fine. Not necessarily. Ransom says that, regardless of their fur, pets still emit the allergy-causing proteins from their skin, glands, dander, urine and saliva.

Plan B Solution

Ransom says if a patient has a severe reaction to animals or develops asthma, he’ll advise that the pet has to go. But “getting people to get rid of pets is very difficult.”

His Plan B is to tell the family to minimize the exposure. First, someone not allergic to the animal should wash it once a week. Next, the pet should never be allowed into the allergy sufferer’s bedroom. The pet’s roaming area in the house should be reduced to exclude areas where the allergic person spends much of his or her time.

Finally, cloth-covered furniture and carpeting – which Ransom calls the “reservoir of allergens” – must be replaced with leather or vinyl furniture and hard floors such as linoleum or tile.

Although some shampoos and sprays claim to reduce how much allergenic protein your pet totes around, Davidson says washing a pet with water alone is probably just as effective. Wipe down a cat with a damp cloth instead of bathing him, the specialist advises, to avoid “losing your forearms.”

The Cat (and its Dander) Comes Back

Removing a pet may not be the end of the story for those with animal allergies. Cat and dog proteins are ubiquitous: one study found the proteins in 100 percent of U.S. homes tested, though only 49 percent actually housed a dog or cat.

Davidson explains that cat protein is dispersed in particles so small that some remain suspended instead of sinking to the ground. Enough protein to cause symptoms can be present for months, or even years after the cat has left the building.

After a pet has been removed, it’s time to get out the rubber gloves, and your wallet. Davidson says drapes, carpet and furniture should all be professionally steam cleaned, particularly if a cat was present, and removing carpets is worthwhile.

“All the dust in the room will contain a lot of cat protein,” he notes, stressing the need to get “onto the top of door jams and into light fixtures.” Ransom adds that if carpeting can’t be removed, brushing tannic acid powder into it, then later vacuuming, also helps to neutralize some allergens.

A Shot in the Arm

Immunotherapy is an option for some people for whom avoidance measures aren’t effective or prove impossible. (One of Davidson’s patients, a veterinary assistant, turned to allergy shots when wearing a mask and antihistamines could not eliminate all of her symptoms.)

Doctors give the desensitizing injections as a series of increasingly higher doses of the problematic animal’s protein, and the treatment can take up to five years. Davidson says these vaccines are more than 80 percent effective in significantly reducing symptoms.

There are risks, however, ranging from minor swelling and irritation at the injection site to anaphylactic reaction. (Davidson estimates there are three to six deaths a year in the U.S. from all allergy shots, with those with poorly controlled asthma at a higher risk.)

Safer Pets for Those With Animal Allergies

What is a good pet for those who duck for cover when the fur and feathers fly? “The textbook answer would be to get a fish or a reptile,” Davidson said, although he suggests “doing an audition” with a pet in your home for two or three days if you’re unsure how you’ll react. Just make sure you can return the pet.

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