Allergies are the result of an immune system run amok. They develop when your immune system overreacts to a normally harmless substance, such as pollen, cat dander, or dust. About one in five Americans are plagued by sneezing, coughing, wheezing, chest tightness, difficulty breathing, itchy eyes, hives, and rashes, which are all hallmarks of allergy symptoms.
Allergies come in almost infinite variety. But most triggers, called allergens, stimulate the immune system through four basic routes: ingestion (eating peanuts or shrimp, for example), injection (such as getting a penicillin shot), absorption through the skin (touching poison ivy), and inhalation (breathing in cat dander).
For food and drug allergies, avoidance is the only option. To prevent or treat contact allergies caused by poison plants, see Poison Plant Rashes. But when you want relief from inhalant allergies, the answer is probably right under your own nose, since house dust, pollen, pet dander, and mold are the most common triggers.
"You find a bit of everything in house dust," says Thomas Platts-Mills, M.D. "Different people are allergic to different things—pieces of cockroach are pretty potent, actually—but the single biggest cause of problems is the dust mite."
The dust mite is an almost microscopic relative of ticks and spiders. But living mites are not the problem. People react, instead, to the fecal material that mites expel on carpets, bedding, and upholstered furniture. The bodies of dead mites also trigger allergies.
When scientists visited 831 residents across the United States in the late 1990s to conduct the first national allergy survey, they discovered that almost one in four houses harbor dust mites. Only the western United States was relatively spared. Cockroach allergens were found in homes throughout America, especially in homes where scientists also found food debris.
The other common airborne allergens are equally hard to escape. Pollen fills the air in almost every region with seasonal regularity. Mold grows wherever it's dark and humid, under carpets, in dank basements, and in leaky garages and storage sheds. And with 75 million dogs and 88 million cats in America, it's not easy to escape pet dander. If you're sensitive to any of these allergens—most likely because you've inherited the tendency—contact with them will trigger a sneezing, wheezing, itchy reaction.
Fortunately, there's much you can do to minimize the misery. The following doctor-tested and recommended tips will plant you firmly on the path to easy breathing and dry eyes.
If you have a known allergy, notice any of the following symptoms, and have never experienced them before during an allergy attack, you should see your doctor.
• Welts that spring up in response to exposure to an allergen, also known as hives. They may indicate the onset of anaphylactic shock, an allergic reaction severe enough to kill. Anaphylactic shock is most commonly associated with bee or fire ant stings, but it can occur in response to other allergens, too. Seek medical attention promptly.
• Wheezing—a whistling sound when you breathe.
• Asthma—congestion of the chest severe enough to make breathing difficult, often accompanied by wheezing.
• An allergy attack that doesn't respond to over-the-counter medications within a week.
David Lang, M.D., is the head of Allergy/Immunology section in the Department of Pulmonary, Allergy and Critical Care Medicine at Cleveland Clinic.
Thomas Platts-Mills, M.D., is a professor of medicine and head of the division of allergy and immunology at the University of Virginia Medical Center in Charlottesville.
Richard Podell, M.D., is a clinical instructor in the department of family medicine at the University of Medicine and Dentistry of New Jersey—Robert Wood Johnson Medical School in Piscataway.