Allergy Glossary

The following is a list of commonly used terms and definitions pertaining to Allergies and their symptoms.


The surgical removal of enlarged adenoids due to impaired nasal breathing or chronic earaches. This procedure is usually done as an outpatient procedure under general anesthesia.


Adenoids are glands or lymphoid tissue in the upper part of throat below the nose.  They are also known as the pharyngeal tonsils or nasopharyngeal tonsils.

Allergic Rhinitis

See Hay Fever.


Allergies are a disorder of the immune system in which the human body has an exaggerated reaction to a substance.  Typically allergies are classified as a skin allergy, insect allergy, food allergy, nasal allergy, or Asthma.

Allergies are inappropriate or exaggerated reactions of the immune system to substances that, in the majority of people, cause no symptoms. Symptoms of the allergic diseases may be caused by exposure of the skin to a chemical, of the respiratory system to particles of dust or pollen (or other substances), or of the stomach and intestines to a particular food.

Allergy index

Measure (from 1-10) of allergy sufferers who are affected by pollen in a geographic region. It should be noted that a high aalergy index does not correlate with a high pollen count, as some different types of pollen trigger different allergies.

Allergy shots

See immunotherapy


Anaphylaxis, or anaphylactic shock, is an acute and severe life-threatening allergic reaction typically caused by an insect sting.  Anaphylatic shock will trigger systemic vasodilation and edema of the bronchial mucosa which makes it difficult to breath.  Anaphylatic shock can lead to death if not treated immediately.

Anaphylaxis may be characterized by symptoms such as lowered blood pressure, wheezing, vomiting or diarrhea, and swelling and hives.


Angioedema is swelling similar to urticaria (hives), however the swelling occurs beneath the skin. Angioedema is characterized by deep swelling typically around the eyes, lips, and possibly the hands and feet.

Anti-inflammatory drugs

Anti-inflammatory drugs reduce the symptoms and signs of inflammation. Although not a drug, immunotherapy (“allergy shots”) reduces inflammation in both allergic rhinitis and allergic asthma.


An important part of the immune system, antibodies are proteins produced by white blood cells (lymphocytes) that circulate in the blood. Antibodies seek and attach to foreign proteins, microorganisms or toxins in order to neutralize them.

Bacteria, viruses and other microorganisms commonly contain many antigens, as do pollens, dust mites, molds, foods, and other substances. Although many types of antibodies are protective, inappropriate or excessive formation of antibodies may lead to illness.

Antibodies are also known as Immunoglobulins.


An antigen is a substance that can trigger an immune response, resulting in production of an antibody as part of the body’s defense against infection and disease. Many antigens are foreign proteins. An allergen is a special type of antigen which causes an IgE antibody response.

Antihistamine drugs

Antihistamines are a group of drugs that block the effects of histamine, a chemical released in body fluids during an allergic reaction.


Asthma is a chronic, inflammatory lung disease characterized by recurrent breathing problems. People with asthma have acute episodes where the air passages in their lungs get narrower, and breathing becomes more difficult. Asthma attacks may be triggered by allergens, although infection, exercise, cold air and other factors are also important triggers.


Bronchitis is an inflammation of the bronchi (lung airways), resulting in a persistent cough that produces large amounts of phlegm.

Bronchodilator drugs

Bronchodilators are a group of drugs that widen the airways in the lungs.


Any of the larger air passages that connect the trachea (windpipe) to the lungs. Also referred to as “bronchus” or “bronchi” in the plural form.


Conjunctivitis is an inflammation of the conjunctiva, the tissue that lines the inside of the eyelid. If the cause is bacterial infection, it is called “pink eye” or bacterial conjunctivitis. If the cause is allergic it is called allergic conjunctivitis.

Contact dermatitis

Contact dermatitis is an inflammation of the skin or a rash caused by contact with a substance.  These substances might be chemical, animal or vegetable based and the inflammation may be an immunologic response or a direct effect of the substance.

Among the more common causes of a contact dermatitis reaction are detergents left on washed clothes, nickel, chemicals in latex, cosmetics, plants such as poison ivy, and topical medications. Symptoms include redness, itching, and sometimes, blistering.

Corticosteroid drugs

Corticosteroids are a group of anti-inflammatory drugs. Corticosteroids are often used in the treatment of asthma, allergic rhinitis, eczema and rheumatoid arthritis.


A common cause of allergic reactions, pet danders are tiny scales shed from animal skin and trap on animal fur or hair. Danders often float in the air, settle on surfaces and are a large component of household dust.


Medication that relieves decreases nasal congestion, mucus secretion, and other nasal tissue related symptoms.  Decongestants work by shrinking swollen nasal tissues.

Digestive system

The digestive system is the group of organs that breaks down food into chemical components that the body can absorb and use for energy and for building and repairing cells and tissues.

Drug allergy

Allergic reaction to a specific medication, such as penicillin.

Dust mites

Dust mites are microscopic mites that feed off of dead skin cells of humans.  Dust mites live in the fibers of pillows, mattresses, blankets and carpet, and inhalation of their droppings can cause allergic reactions such as nasal congestion.


An inflammation of the skin which usually results in itching and might be accompanied by crusting, scaling or blisters.

Elimination diet

A diet in which certain foods are temporarily discontinued from the diet to rule out the cause of allergy symptoms.  Once it has been determined that the patient does not have an allergic reaction to a food, it may be reintroduced to their diet.


Enzyme-linked immunosorbent assay, is a blood test used to identify the substances that are causing allergy symptoms and to estimate a relative sensitivity to a substance.

Epinephrine (adrenaline)

Epinephrine is a naturally occurring hormone, also called adrenaline. It is a chemical released by the adrenal gland, and it increases the speed and force of heart beats.  This is turn increases the work that can be done by the heart.

The release of Epinephrine dilates the airways which improves breathing, and narrows blood vessels in the skin and intestine so that blood flow can be increased to the muscles.  This reaction allows the muscle to deal with increased demands.

Synthetic Epinephrine is used to treat anaphylaxis.

Extrinsic asthma

Extrinsic asthma is asthma that was caused by an allergic reaction due to something being inhaled.

Food allergy

Allergic reaction triggered by the ingestion of a particular food protein.

Hay Fever

See Rhinitis.


HEPA stands for “High-efficiency particulate air”.  A HEPA filter removes particles in the air by forcing it through screens containing microscopic pores.


Histamine is a chemical that is released during an allergic reaction. Histamine is one of the causes of inflammation as well as the running of the nose, sneezing, and itching in allergic rhinitis. Histamine also stimulates production of acid by the stomach and narrows the bronchi or airways in the lungs.


See Urticaria.


Products made with the fewest allergens possible.

Immune system

The immune system is the body’s defense system, which is made up of a collection of cells and proteins that work to protect the body from infectious microorganisms, such as bacteria, viruses and fungi. While the immune system plays a role in the control of diseases such as cancer, it also is the reason why people have allergies, as the immune system fights off allergens.


See Antibodies


Immunotherapy, or allergy shots, is a form of preventive and anti-inflammatory treatment of allergy to substances such as pollens, house dust mites, fungi, and stinging insect venom.

Immunotherapy involves giving gradually increasing doses of the substance to which the person is allergic. The immune system then becomes less sensitive to the substance, which reduces the symptoms of allergy when the substances is encountered in the future.


Inflammation is the redness, swelling, heat and pain in a tissue due to chemical or physical injury, or as part of fighting infection.

Intrinsic asthma

Intrinsic asthma is asthma that is not caused by an external substance, such as something that was inhaled.


Latex is a milky fluid derived from the rubber tree. It is used in a wide variety of consumer products such as rubber gloves, tubing, and rubber bands to name a few.  Latex can also cause an allergic skin reaction in some individuals.


A lymphocyte is a group of white blood cells which attack dangerous substances inside the body.  This is a key part of the immune system.

Mast cell

Mast cells are an important part of the body’s defense system against allergies, particulary regarding the skin.  In the event that there is an allergic response, antibodies are released and attach themselves to mast cells.  In subsequent allergen exposures, mast cells release substances such as histamine into the tissue, which then trigger allergy sympstoms.

Metered dose inhaler (MDI)

Commonly referred to as an inhaler, a MDI is a small aerosol canister in a plastic container that releases a burst of medication when pressed down from the top. This is commonly how asthma medication is taken.


Parasitic, microscopic fungi typically found in damp areas such as basements and bathrooms.  Mold can also float in the air like pollen, and can trigger allergies.

Mold count

See pollen and mold count


A surgical procedure where a tiny incision is made in the eardrum to relieve pressure caused by the excessive build up of fluid.

Myringotomy with tubes

The placement of small metal or plastic tubes in the eardrum to equalize the pressure between the middle and outer ear.

Nasal endoscopy

The use of a fiberoptive camera to evaluate the nasal cavity for polyps or other abnormalties.

Nasal sprays

Nasal sprays are prescription and over-the-counter medications used to alleviate the symptoms associated with nasal allergies.

Otitis media

An infection of the middle ear.


A doctor which specializes in diagnosing and treating the ears, nose and throat.  Commonly referred to as an ENT physician.


An instrumant used by physicians to view the outer ear canal.

Pneumatic otoscope

An instrument used to test eardrum movement by blowing a puff of air into the ear canal.


A fine coarse powder produced by seed plants.

Pollen and mold counts

A measure of the amount of allergens in the air, reported as grains per cubic meter of air.  This measurement is reported as one of four levels: absent, low, medium, or high.  The counts are also reported for mold spores and three types of pollen: grasses, trees and weeds.

Pulmonary function test

A test measuring how much air is in a human’s lungs and how forcefully they can exhale this air.


RadioAllergoSorbent Test (RAST) is a trademark of Pharmacia Diagnostics, and is a laboratory test used to detect IgE antibodies to specific allergens.

Respiratory system

The respiratory system is the group of organs (airways, lungs, respiratory muscles) responsible for carrying oxygen from the air to the bloodstream and for expelling the waste product carbon dioxide.


Rhinitis is an inflammation of the mucous membrane that lines the nose, often due to an allergy to pollen, dust or other airborne substances. Seasonal allergic rhinitis also is known as “hay fever,” a disorder which causes sneezing, itching, a runny nose and nasal congestion.


The sinuses are air cavities lined by mucous mebranes within the facial bones.


Sinusitis is inflammation of the air cavities in within the facial bones, often caused by bacterial or viral infection.


Urticaria, commonly referred to as hives, is the development of itchy, raised bumps surrounded by redness on the skin.

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