Allergy: A hypersensitivity of the body's immune system in response to exposure to specific substances (antigens), such as pollen, beestings, poison ivy, drugs, or foods. Anaphylactic shock is a severe form of allergy response which is a medical emergency. Symptoms of anaphylactic shock include dizziness, loss of consiousness, labored breathing, swelling of the tongue and breathing tubes, blueness of the skin, low blood pressure, and death.
Allergen: A substance that can trigger an allergic reaction. Asthma can be triggered by dust mites, animal dander, mold, and cockroaches.
Hives: Elevated patches on skin usually caused by an allergic reaction accompanied by a release of histamine into the body tissues. Patches are redder or paler than the surrounding skin and itch intensely.
Antibodies: Protein produced by white blood cells, which neutralize or destroy foreign proteins in the body (antigens). When infected with virus or bacteria, the body produces antibodies, which destroy the invading microorganisms.