Allergy Slideshow Pictures: 10 Common Allergy Triggers

Reviewed by Varnada Karriem-Norwood, MD on Monday, September 26, 2011

Uncover your allergy triggers

Nearly 20% of Americans suffer from allergies. Allergies are an abnormal response of the immune system where the body's defenses react to a usually harmless substance in the environment, such as pollen, animal dander, or food. Almost anything can trigger an allergic reaction, which can range from mild and annoying to sudden and life-threatening. Here are 10 of the most common triggers.

Pollen

Exposure to pollen from trees, grasses, and weeds can trigger hay fever or seasonal allergies. Symptoms include sneezing, runny nose, nasal congestion, and itchy, watery eyes. Treatments include over-the-counter products, prescription drugs, and allergy shots. Prevent symptoms by staying indoors on windy days when pollen counts are high, closing windows, and running the air conditioning.

Seen here is a magnified view of sunflower pollen.

Animal Dander

Proteins secreted by oil glands in an animal's skin and present in their saliva can cause allergic reactions for some. The allergy can take two or more years to develop and symptoms may not subside until months after ending contact with the animal. If your pet is causing allergies, make your bedroom a pet-free zone, avoid carpets, and wash the animal regularly. A HEPA filter and frequent vacuuming may also help. Allergy shots may be beneficial.

Dust Mites

Dust mites are microscopic organisms that live in house dust. They thrive in areas of high humidity and feed on the dead skin cells of humans and their pets, as well as on pollen, bacteria, and fungi. Help prevent dust mite allergies by covering mattresses, pillows, and box springs, using hypoallergenic pillows, washing sheets weekly in hot water, and keeping the house free of dust collecting-items such as stuffed animals, curtains, and carpet.

Insect Stings

People who are allergic to stings can have a severe or even life-threatening reaction. Symptoms include extensive swelling and redness from the sting or bite that may last a week or more, nausea, fatigue, and low-grade fever. Rarely, insect stings may cause anaphylaxis, with symptoms including difficulty breathing, hives, swelling of the face, throat, or mouth, rapid pulse, dizziness, or a sharp drop in blood pressure. For those severely allergic, epinephrine should be administered immediately after a sting; allergy shots are recommended to prevent anaphylaxis with future stings.

Molds

Molds produce allergens, irritants, and in some cases, potentially toxic substances. Inhaling or touching mold (magnified here) or mold spores may cause allergic reactions in sensitive individuals. There are many types of mold; all need moisture to grow. They can be found in damp areas such as basements or bathrooms, as well as in grass or mulch. Avoid activities that trigger symptoms, such as raking leaves. Ventilate moist areas in the home.

Food

Milk, shellfish, nuts and wheat are among the most common foods that cause allergies. An allergic reaction usually occurs within minutes of eating the offending food. Symptoms, which can include asthma, hives, vomiting, diarrhea, and swelling around the mouth, can be severe. Avoid offending foods altogether; but if exposed, treatment with antihistamines or steroids is recommended. In life-threatening situations, an epinephrine injection is needed.

Latex

Latex in gloves, condoms, and certain medical devices can trigger latex allergy. Symptoms include skin rash, eye irritation, runny nose, sneezing, wheezing, and itching of the skin or nose. Allergic reactions can range from skin redness and itching to anaphylaxis, a serious reaction which can cause difficulty breathing, hives. Those allergic should wear a MedicAlert bracelet and carry an epinephrine kit.

Medication

Symptoms of allergies to medications, such as penicillin or aspirin, can range from mild to life-threatening and can include hives, itchy eyes, congestion, and swelling in the mouth and throat. It's best to avoid the drug altogether; however, if exposed, treatment with antihistamines or steroids is recommended. For coughing and lung congestion, bronchodilators may be prescribed. For severe symptoms, epinephrine may be needed.

Fragrance

Fragrances found in products including perfumes, scented candles, laundry detergent, and cosmetics can have mild to severe health consequences. For most people, symptoms abate once the scent is out of range. For some, repeated exposures cause an increase in symptoms that occur more often and last longer. There's some debate as to whether fragrance reactions are a true allergy or simply a response to an irritant.

Cockroaches

Ick! Not only are cockroaches creepy, but a protein in their droppings can be a troublesome allergen. It can be difficult to eradicate cockroaches from your home, especially in a warm climate, or if you live in an apartment building where bugs can pass back and forth to a neighboring unit. Treat for roaches by using pesticides, keeping a clean kitchen, and repairing cracks and holes in floors, walls, and windows to prevent their entry into the home.