Allergies

Allergies
An allergy is any hypersensitivity reaction by the body to a foreign substance (antigen). Allergies are often reactions to foods, pollens, or microorganisms such as bacteria, fungi, or parasites. Allergens (allergy-causing substances) can be airborne, like dust, lint, and smoke, or they can be things one comes in contact with, such as chemicals, dyes, and poisonous plants. Even heat, cold, and light - as from the sun - can be allergens.