Allergies to Animals

Excerpted from
Allergic to Pets? The Breakthrough Guide to Living with the Animals You Love
By Shirlee Kalstone

The primary focus of this book is allergic reactions to pets that live indoors (as well as horses) and secondarily, to the other indoor airborne allergens in our homes. As you read in the previous chapter, coming into contact with your pet can cause hives or a skin rash when you touch or otherwise handle the animal. More common, though, are sensitivities to pets from airborne allergens. Microscopic flakes of dried secretions from the animal's skin, saliva, and urine circulate through the air and, when you inhale them, your immune system shifts into overdrive to protect you. As a result, you sneeze and get a stuffy or runny nose, and suffer from other symptoms of allergic rhinitis.

Rhinitis is the most common allergy; millions of Americans suffer from it. Allergic rhinitis takes two different forms: seasonal and perennial. Seasonal allergic rhinitis is caused by sensitivity to pollens, trees, grasses, weeds, and airborne mold spores. Symptoms generally surface in spring, summer, or early autumn, depending on where you live. Perennial allergic rhinitis, as its name implies, is a year-round problem caused by sensitivities to a range of indoor allergens including dust mites, molds, cockroaches, and, most importantly for readers of this book, allergens from pets with hair, fur, or feathers. People can have both seasonal and perennial allergies.

Allergies to pets can vary dramatically between individuals. In some cases, merely walking into a house where a car or dog lives may be enough to produce an allergic reaction within minutes. In other cases, an allergy can develop over time and exposure, and may not occur until a pet has been in your home for years. And occasionally, an allergic person develops a tolerance to symptoms and is able to live harmoniously with a pet, but why a specific individual becomes desensitized is not clear. An abstract published in 2003 reports that "increasing evidence shows that exposure to cats, dogs, and other animals can induce a form of immunologic tolerance without causing allergic disease."

The Animals That Cause Allergies

Any warm-blooded animal with hair, fur, or feathers can cause allergies in humans at home or at work: cats, dogs, horses, rabbits, ferrets, gerbils, guinea pigs, hamsters, chinchillas, mice, rats, monkeys, goats, sheep, cattle, pigs and other farm animals, donkeys, mules, zebras, all species of large cats, and all kinds of birds, including chickens, turkeys, ducks, and geese. Cats, by far, cause the most allergic reactions, followed by dogs, rabbits, and horses. Let's focus for a moment on cats and dogs, the most popular housepets in the United States.

All cats and dogs-purebred, mixed-breed, short-haired, long-haired, wire-haired, curly-haired, and even hairless-are potentially allergenic. However, choosing the right cat, and especially the right dog, may make a big difference in successfully managing your child's, spouse's, significant other's, or your own allergies. What is important is not so much the length or amount of hair, but the quantity of hair that is or is not shed. All cats and dogs (except hairless breeds) shed, but those that shed excessively seem to trigger more sensitivities, due to the excessive amount of allergens the dead hair may carry. And when pets have an illness or skin condition that leads to excessive shedding, more dander is temporarily produced. Most people think short-hairs don't shed much around the house but, in fact, they shed a great deal and can spread as many allergens into the environment as pets with medium or long hair. Others may have more problems with double-coated pets (a longer outer coat with soft undercoat), especially dogs that shed profusely. Pets with soft, curly, or silky hair (with no undercoats) seem to cause fewer allergy problems.

While some animals may produce more or less allergens than others, there are no "hypoallergenic" cats or dogs. We know that some dogs and cats produce far more allergens than others but the differences are not specific to any particular breed. In fact, studies have found that the differences in allergen production within a single breed can be as great (or even greater) than the differences between multiple breeds. Studies also show that allergen production is controlled by hormones: males produce more allergens than females, and when males are castrated, the amount of allergens produced decreases within a month. Still, according to Dr. Robert A. Wood, of Johns Hopkins University, "It is not possible to predict with any accuracy which animals are likely to be more or less allergenic based on a particular breed, size, hair length, or propensity to shed."

Animals that do not disperse allergens into the environment and are nonirritating are those with no hair, no fur, and no feathers: fish, snakes, turtles, lizards, frogs, toads, and so forth. These are the only 'safe" pets for allergy sufferers. But be aware of the mold that can accumulate on damp fish tank lids.

Identifying the Major Animal Allergens

There are several sources of pet-related allergens, all accomplishing the same end: being inhaled into your lungs and triggering allergic or asthmatic reactions. They are:

• Secretions from the sebaceous glands of the skin, located at the base of the hair follicles. These are oily lubricants that keep the skin supple; they are deposited on the hairs inside the follicles and brought up to the surface of the skin along the hair shaft.

• Saliva spread on hair or fur when an animal licks or cleans itself.

• Urinary secretions that are frequently deposited on the hair, especially on long-coated animals.

All these are liquid proteins that are microscopically small, and light enough to remain airborne almost indefinitely. Equally important is an animal's dander-dead particles that shed regularly from the skin and are similar, but much smaller in size, to skin cells that exfoliate from your own body and scalp. Combine all these particles and you virtually load your home with pet allergens.

Pet hair itself is not an allergen; it merely serves as a carrier. The sebaceous gland, salivary, and urinary allergens dry on the hair and subsequently flake off into the environment, along with dander, to become airborne for extended periods of time.