Allergies - Glossary

Adenoids
Glands or lymphoid tissue in the upper part of throat below the nose, also known as the pharyngeal tonsil.

Adenoidectomy
The surgical removal of enlarged adenoids to help prevent blockage of the eustachian tubes and ear infections. This is usually done as an outpatient procedure under general anesthesia.

Allergen
A substance that your body perceives as foreign and harmful; initiates the 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.

Allergy index
Measure (from 1-10) 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 characterized by 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 white blood 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, that the body perceives as foreign.

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

Antiinflammatory
Type of medication that reduce swelling and mucus production, particularly for asthma and rhinitis.

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 can cause a feeling of not getting enough air into the lungs or shortness of breath.

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. Danders float in the air, settle on surfaces and make up much household dust. Cat danders are 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.

Drug allergy
Allergic reaction to a specific medication. The most common cause of drug allergies is penicillin.

Dust mites
A common trigger for allergies.

Elimination diet
A diet in which certain foods are temporarily discontinued from the diet to rule out the cause of allergy symptoms.

ELISA (enzyme-linked immunosorbent assay)
Blood test used to identify the substances that are causing your allergy symptoms and to estimate a relative sensitivity.

Epinephrine
A form of adrenaline medication used to treat severe allergic reactions, such as anaphylactic shock or insect stings. It is available in self-injectable form or can be injected by a health care provider.

Food allergy
Allergic reaction that occurs when the immune system responds defensively to a specific food protein when ingested.

Hay fever
Allergic reaction caused by the pollens of ragweed, grasses and other plants whose pollen is spread by the wind.

HEPA
High-efficiency particulate air (HEPA) filter which removes particles in the air by forcing it through screens containing microscopic pores.

Histamine
A naturally occurring substance that is released by the immune system after being exposed to an allergen. When you inhale an allergen, mast cells located in the nose and sinus membranes release histamine. Histamine then attaches to receptors on nearby blood vessels, causing them to enlarge (dilate). Histamine also binds to other receptors located in nasal tissues, causing redness, swelling, itching and changes in the secretions.

Hives
See urticaria

Hypoallergenic
Products formulated to contain the fewest possible allergens.

Immune system
The body’s defense system that protects us against infections and foreign substances.

Immunotherapy
Also called allergy desensitization or allergy shots; immunotherapy is given to increase a person’s tolerance to the substances that provoke allergy symptoms (allergens). Allergy shots reduce your sensitivity to certain substances. They are usually recommended for people who have allergic symptoms more than 3 months a year.

Latex
Also known as rubber or natural latex. Latex is a milky fluid derived from the rubber tree. It is used in a wide variety of consumer products, including rubber gloves, tubing, rubber bands, etc.

Latex allergy
An allergy that develops after some sensitizing contact with latex.

Metered dose inhaler (MDI)
Small aerosol canister in a plastic container that releases a burst of medication when pressed down from the top. Many asthma medications are taken using a MDI.

Mold
Parasitic, microscopic fungi (like Alternaria) that float in the air like pollen. Mold is a common trigger for allergies and can be found in damp areas, such as the basement or bathroom, as well as in the outdoor environment in grass, leaf piles, hay, mulch or under mushrooms.

Mold count
See pollen and mold count

Myringotomy
Outpatient procedure in which small metal or plastic tubes are inserted through the eardrum to equalize pressure between the middle and outer ear.

Nasal endoscopy
A test that allows the doctor to view the nasal cavity to detect polyps or other abnormalities.

Nasal sprays
Medication used to prevent nasal allergy symptoms. Available by prescription or over-the-counter in decongestant, corticosteroid or salt-water solution form.

Otitis media
Bacterial or viral infection of the middle ear (the space behind the eardrum).

Otolaryngologist
A physician who specializes in diagnosing and treating a variety of disorders of the ear, nose and throat (ENT), as well as performing surgery of the ear, nose and throat. Also known as an ENT physician.

Otoscope
A lighted instrument that lets the physician see far down into the outer ear canal.

Pneumatic otoscope
An instrument that blows a puff of air into the ear canal to test eardrum movement.

Pollen
A fine, powdery substance released by plants and trees

Pollen and mold counts
A measure of the amount of allergens in the air. The counts are usually reported for mold spores and three types of pollen: grasses, trees and weeds. The count is reported as grains per cubic meter of air and is translated into a corresponding level: absent, low, medium or high.

Pulmonary function test
A test that measures how much air is in the lungs and how forcefully this air can be exhaled (lung function).

RAST (radioallergosorbent test)
Blood test used to identify the substances that are causing your allergy symptoms and to estimate a relative sensitivity.

Sinusitis
Inflammation of the sinuses caused by bacterial infection. Acute sinusitis is the sudden onset of symptoms that can be treated with antibiotics and decongestants. Chronic sinusitis is characterized by at least four recurrences of sinusitis or infection that last 12 weeks or longer.

Tympanometry
A test in which sound and air pressure are used to check for fluid in the middle ear.

Urticaria (hives)
Itchy, swollen, red bumps or patches on the skin that appear suddenly as a result of the body’s adverse reaction to certain allergens. They can appear anywhere on the body including the face, lips, tongue, throat or ears. Hives vary in size and can last for minutes or days.