Many things can trigger an allergic reaction. That's when your body's defenses attack a usually harmless substance, such as pollen, animal dander, or food. The reaction can range from mild and annoying to sudden and life-threatening. About 1 in 5 Americans have allergies.
Pollen from grasses, trees, and weeds can trigger hay fever or seasonal allergies. You might be sneezing and have a runny or stuffy nose and itchy, watery eyes. Treat these with over-the-counter products, prescription drugs, and allergy shots. To prevent symptoms, stay inside on windy days when pollen counts are high, close windows, and run the air conditioning.
Pictured is a magnified view of sunflower pollen.
A reaction to proteins in an animal's saliva or in oil glands in their skin might take 2 years or longer to become an allergy. If your pet is the trigger, you may still be able to live with him. Make your bedroom a pet-free zone, opt for bare floors and washable rugs instead of carpets, and bathe him regularly. A HEPA filter and allergy shots may help, too.
Dust mites are tiny bugs that live in bedding, mattresses, upholstery, carpets, and curtains. They feed on dead skin cells from people and pets, as well as on pollen, bacteria, and fungi. They thrive in high humidity. To cut down on problems, use hypoallergenic pillows, cover mattresses, pillows, and box springs, and wash sheets weekly in hot water. Keep the house free of dust-collecting items such as stuffed animals, curtains, and carpet.
A sting or bite could cause swelling and redness that may last a week or more. You might feel sick to your stomach and tired and have a low fever. In rare cases, insect bites trigger a reaction that can be life-threatening, called anaphylaxis. If you're severely allergic, you'll need epinephrine right away. Your doctor may recommend allergy shots to prevent reactions.
Mold needs moisture to grow. It can be found in damp places such as basements or bathrooms, as well as in grass or mulch. Since breathing in or touching mold (magnified here) or mold spores can set off an allergic reaction, avoid activities that could trigger symptoms, such as raking leaves. Get air moving in moist areas of your home.
Milk, shellfish, eggs, and nuts are among the most common foods that cause allergies. Within minutes of eating the trigger food, you could have trouble breathing and get hives, vomiting, diarrhea, and swelling around your mouth. If your reaction is severe, you may need a shot of epinephrine.
Latex in gloves, condoms, and some medical devices can trigger a reaction ranging from itchy, red skin to anaphylaxis with trouble breathing. Symptoms can include a rash or hives, eye irritation, runny or itchy nose, sneezing, and wheezing. If you have a latex allergy, wear a medical alert bracelet and carry an epinephrine kit.
Penicillin, aspirin, and other drugs can cause hives, itchy eyes, stuffiness, and swelling in your face, mouth, and throat. If you're allergic to a drug, it's best to not take it. But if you do, your doctor could recommend treating mild symptoms with antihistamines or steroids. For severe symptoms, which can be life-threatening, you may need epinephrine.
Not only are cockroaches creepy, but a protein in their droppings can be a trigger. Roaches can be tough to get rid of, especially in a warm climate or if you live in an apartment building where they can pass back and forth between neighbors. Treat them with bug killer, and keep a clean kitchen. Repair cracks and holes in floors, walls, and windows to keep them out of your home.
(1) Altrendo images
(2) Susumu Nishinaga / Photo Researchers, Inc.
(3) Chris Amaral / Digital Vision
(4) David Scharf / Science Faction
(5) Charles Krebs / Science Faction
(6) Dennis Kunkel Microscopy
(7) Food Image Source / StockFood Creative
(8) PhotoAlto / Ale Ventura
(9) M Stock - The Stock Connection / Science Faction
Aerias Air Quality Sciences IAQ Resource Center.
American Academy of Allergy, Asthma & Immunology.
American Academy of Dermatology.
American Academy of Family Physicians.
American Academy of Ophthalmology.
American Academy of Pediatrics.
Asthma and Allergy Foundation of America.
Children's Hospital Boston.
Halken, S. Journal of Allergy and Clinical Immunology, January 2003.
National Institute of Allergy and Infectious Diseases.
The Food Allergy Initiative.
University of Kentucky College of Agriculture.
THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for general informational purposes only and does not address individual circumstances. It is not a substitute for professional medical advice, diagnosis or treatment and should not be relied on to make decisions about your health. Never ignore professional medical advice in seeking treatment because of something you have read on the WebMD Site. If you think you may have a medical emergency, immediately call your doctor or dial 911.