Even a shorthair (or hairless, like this Canadian Sphynx kitten) can cause allergies in humans.

Photo courtesy Oleg Nikishin/Getty Images

Fel d 1 and You

It's not your cat's fault that you are allergic to it. Most cat allergies result from a reaction to the Fel d 1 glycoprotein, which cats secrete through their skin and saliva. This glycoprotein is smaller than dust and can hang around your home for months [source: Asthma and Allergy Foundation of America].

A person's best bet for reducing pet allergies is avoiding pets altogether, says the Asthma and Allergy Foundation of America. But living a pet-free life simply won't do for some people. As such, pet owners who have allergies have developed some tips for cutting down on the allergic effects. Washing your cat twice a week, avoiding wool sweaters, opting for females or neutered male cats and keeping only short-haired cats are all examples of plausible ways to help cut down on allergic reactions to cats [source: Cat World].

The problem is that there's no such thing as a hypoallergenic cat -- that is, until now. So allergic cat owners have traditionally had to look to the field of medicine for relief. And it's not just cat owners who suffer -- dog, horse, and even bird owners can suffer similar allergies.

The Fel d 1 glycoprotein, however, is naturally produced exclusively by cats (the "Fel" is short for "feline"). Cats emit the allergen through their saliva or skin, so when you pet a cat or it licks you, the Fel d 1 protein is transmitted. It can also rub off on anything the cat touches -- especially fibers -- and the protein is tough to get rid of. What's worse, this allergen can be transferred from a home where a cat lives to other cat-free places. The allergen can also build up quickly, which was proven by a study of a mattress store in Sweden. ­ [source: National Center for Biotechnology Information]. Researchers found that new mattresses in stores had high levels of allergens just from customers who own pets trying out the mattresses.

The Fel d 1 protein can cause a bad reaction is some humans. People with sensitized immune systems have undergone a process of becoming allergic. After being exposed to the glycoprotein, the sensitized person's body creates immunoglobin E (IgE) -- an antibody to fight what the body sees as an invader. (In people who don't become sensitive to pets, the Fel d 1 glycoprotein is basically inert -- it has no effect.) The next time the person encounters the protein, the body releases the IgE antibodies. These, in turn, trigger a release of histamines -- a compound that relaxes the capillaries and smooth muscle tissue, allowing them to become more permeable. This makes the soft tissue areas around the eyes, nose and throat become much more sensitive to everyday irritants. So allergy sufferers end up with watery eyes, runny noses and scratchy throats [source: Mayo Clinic].

At its worst, the Fel d 1 glycoprotein can even cause asthma in allergy sufferers. This is not uncommon. A study published by the National Institute of Health showed that about 50 percent of asthma cases were allergy-related and that 30 percent of those cases came from cat allergies [source: NIH].

So how did Allerca come up with the hypoallergenic cat? Read the next page to find out.