Allergies occur when the immune system mistakes a normally harmless substance for a dangerous invader and produces antibodies that remain on the alert for that particular allergen. When youre exposed to the allergen again, these antibodies can release a number of immune system chemicals, such as histamine, that cause allergy symptoms. The most common allergy triggers include:
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Pollen: Pollen is microspores from trees, grass or weeds that appear as a fine dust on surfaces or float in the air. Tree pollens generally appear in the spring, while weed pollens generally appear in the fall.
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Dust mites: Dust mites are tiny creatures that live in house dust and feed on dead skin cells. They are found in bedding, upholstered furniture, and carpeting.
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Mold: Mold is a type of fungus that grows in damp environments, such as bathrooms, kitchens, and basements. It can also grow outdoors in humid weather.
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Animal dander: Animal dander is tiny flakes of skin, hair, or feathers from pets such as cats, dogs, birds, and rodents.
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Insect stings: Insect stings from bees, wasps, hornets, and fire ants can cause allergic reactions in some people.
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Latex: Latex is a type of rubber used in many products, such as gloves, balloons, and condoms. Some people can develop an allergy to latex.
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Certain foods: Common food allergens include milk, eggs, peanuts, tree nuts, soy, wheat, fish, and shellfish. Symptoms of a food allergy can range from mild to severe and can include itching, hives, swelling, and difficulty breathing.
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Certain medications: Medications such as antibiotics, nonsteroidal anti-inflammatory drugs (NSAIDs), and insulin can cause allergic reactions in some people.
If you have an allergy, you're more likely to have asthma, which is a chronic lung disease that inflames and narrows the airways.
