Allergies are an overreaction of the body's immune system to specific substances that it misidentifies as harmful. This overreaction of the body's immune system is known as an allergic reaction and the substances that cause it are called allergens. Potential allergens can be anything from dust mites and pollen to insect stings, fragrances, and foods such as shellfish and peanuts. Whatever the allergen, allergic reaction symptoms can be miserable, ranging from a runny nose and watery eyes to breathing problems, diarrhea, hives, and even death.

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