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Allergies Health Center

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Allergy Terms

Adenoids: Glands or lymphoid tissue in the upper part of the throat behind the nose.

Adenoidectomy: The surgical removal of adenoids which may help prevent blockage of the nasal passageways and eustachian tubes. This may help to reduce recurrent sinus and ear infections, among other conditions. This is usually done as an outpatient procedure under general anesthesia.

Allergen: A substance that your body perceives as dangerous and causes an allergic reaction.

Allergic rhinitis: See Hay fever

Allergy: An exaggerated response to a substance or condition produced by the release of histamine or histamine-like substances in affected cells in the body.

Allergy index: Measure of allergy sufferers who are affected by pollen in your region. Since some types of pollen may be more likely to cause allergies than others, a high allergy index does not necessarily correspond to a high pollen count.

Allergy shots: See Immunotherapy

Anaphylaxis: Severe, life-threatening allergic response that may include lowered blood pressure, swelling, and hives.

Angioedema: Swelling similar to urticaria (hives), but the swelling occurs beneath the skin instead of on the surface. Angioedema is characterized by deep swelling around the eyes and lips and sometimes of the hands and feet.

Antibodies: Specialized proteins produced by lymphoid cells (B cells) that circulate in the blood. Antibodies seek and attach to foreign proteins, microorganisms, or toxins in order to neutralize them. They are part of the immune system.

Antigen: A substance, usually a protein, which the body perceives as foreign.

Antihistamine: Medication that prevents symptoms of congestion, sneezing and itchy, runny nose by blocking histamine receptors.

Anti-inflammatory: Type of medication that reduces swelling and inflammation.

Asthma: A disease of the branches of the windpipe (bronchial tubes) that carry air in and out of the lungs. Asthma causes the airways to narrow, the lining of the airways to swell, and the cells that line the airways to produce more mucus. These changes make breathing difficult and cause a feeling of not getting enough air into the lungs.

Bronchodilators: Medications used to relax the muscle bands that tighten around the airways during an asthma episode. Bronchodilators also help clear mucus from the lungs.

Conjunctivitis: Also called "pink eye." Conjunctivitis is an inflammation of the conjunctiva, the tissue that lines the inside of the eyelid.

Dander, animal: Tiny scales shed from animal skin or hair. Dander floats in the air, settles on surfaces and makes up much household dust. Pet dander is a classic cause of allergic reactions.

Decongestant: Medication that shrinks swollen nasal tissues to relieve symptoms of nasal swelling, congestion, and mucus secretion.

Dermatitis: Inflammation of the skin, either due to direct contact with an irritating substance or to an allergic reaction. Symptoms include redness, itching, and sometimes blistering.

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WebMD Medical Reference provided in collaboration with the Cleveland Clinic

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