They result from the immune system overreacting to foreign particles like pet dander, pollen, dust mites, and food proteins. An initial encounter prompts the body to produce antibodies against the particle, or allergen. When a person is exposed again, the allergen triggers the antibodies to bind mast cells, and they release other inflammatory agents such as histamine and leukotrienes, which cause the runny noses, coughing, and watery eyes, collectively known as allergic rhinitis. Most people just call it miserable.
Asthma and eczema (or allergic dermatitis), to name just two. The extreme reactions, often after someone is stung by an insect or eats something made with peanuts, can induce anaphylaxis. When this happens, blood vessels dilate rapidly, causing precipitous, sometimes fatal drops in blood pressure. Atopy is the term used to describe all types of allergic reactions.
People with allergies frequently take histamine and leukotriene blockers. Scientists want to find ways ...
