Glossary of Terms

Medical jargon and terminology can be a bit confusing. We offer this glossary to help you gain confidence in reading the available literature. If there are terms you would like to see added, please contact us.

To use the glossary, click on the first letter of the word and then select the word you want. For an excellent resource on Internet terminology, you might be interested in Health Canada's Glossary of Internet terms.





of unknown causation.

Ig: immunoglobulin of any of the five classes (IgA, IgD, IgE, IgG or IgM).
Immediate Hypersensitivity: hypersensitivity (allergic reaction) that develops without delay.
Immune: characterized by the capacity to distinguish foreign material from self and to react via the immune response following antigenic challenge (exposure).
Immunity: the capacity to distinguish foreign material from self, and to react via the immune response.
Immunization: the process of creating immunity in an individual.
Immunoglobulin: a protein of animal origin endowed with specific antibody activity. Immunoglobulins are found in serum and other body fluids and tissues (saliva, urine, spinal fluid, and lymph nodes). There are five classes of immunoglobulin (IgA, IgD, IgE, IgG, and IgM). IgE is involved in allergy.
Intolerance: inability to absorb or metabolize nutrients (e.g. lactose intolerance).
Intradermal: within skin.
Intramuscular: within muscle (as in an intramuscular injection).
Intravascular: within a blood vessel.
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Kilogram: 1000 grams in metric weight or the equivalent of 2.2 pounds.
Kinins: a group of endogenous (produced in the body) peptides (the component part of proteins) which act on smooth muscle and blood vessels.
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Lactalbumen: an albumin (protein) found in milk.
Lactoprotein: a protein derived from milk.
Lactose: a sugar present in milk, to which some people may be intolerant due to an enzyme deficiency.
Larynx: the uppermost part of the airway; it prevents food from entering the lungs and contains the vocal cords.
Latex: a viscid, milky juice secreted by some seed plants. It is the source of rubber.
Lecithin: any of a group of phospholipids found in animal tissues, particularly nerve, liver, semen and egg yolk.
Legume: any of a large family of plants (Leguminosae) which includes peas, beans, lentils, chickpeas, and peanuts.
Livetin: a protein found in egg yolk.
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Mast cell: a connective tissue cell that contains histamine that is released during allergic reactions.
Mediator: an object or substance through which an effect is obtained; e.g. histamine is one mediator of anaphylaxis.
Medic-Alert: The Canadian Medic Alert Foundation houses a registry of medical information for its members that can be called upon in an emergency. It provides bracelets and necktags inscribed with specific information and their phone number.
Metabolite: any substance produced by metabolism (the transformation by which energy is made available for the use of an organism).
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Oral: by mouth.
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Parenteral: by some means other than the digestive tract; i.e. intravascular or intramuscular injection etc.
Peptide: the constituent part of a protein; each peptide consists of at least two amino acids.
Priority Allergen List: the list of allergens recognized by government and food manufacturers to be of potential concern for anaphylactic consumers.
Protein: any of a complex group of molecules composed of amino acids.
Pruritus: itching.
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Q.I.D.: four times a day. (Quattuor in Die)
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RAST: radioallergosorbent test; a blood test sometimes used to assess allergy.
RCT: randomized controlled trial.
Randomized Controlled Trial: a clinical trial in which participants are assigned randomly to treatment groups. Ideally it is also double blind and neither the investigator nor the participants are aware of the nature of the treatment given.
Relapse: return of disease/symptoms after an apparent cessation.
Rhinitis: inflammation of the mucous membranes of the nose; e.g. allergic rhinitis.
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Sensitization: the initial exposure of an individual to a specific allergen, resulting in an immune response; further exposure usually induces a stronger response.
Serum: the clear portion of any animal fluid separated from its solid elements; e.g. the fluid that separates from clotted blood.
Shock: a condition of acute peripheral circulatory failure due to derangement of circulatory control or loss of circulating fluid. It is characterized by hypotension, coldness of the skin, rapid heart rate (usually), and often anxiety. Anaphylactic s., the violent onset of symptoms produced on second exposure to allergenic protein in an anaphylactic individual.
Skin test: the application of a pollen or protein onto a skin abrasion or by intradermal injection in order to assess allergic sensitivity.
Steroid: a group name for compounds that contain a specific chemical ring system; included are a group of hormones produced by the adrenal cortex and synthetically; they may be administered to reduce the symptoms of an allergic reaction.
Stridor: a harsh, high-pitched breath sound associated with significant laryngeal obstruction.
Subcutaneous: beneath the skin.
Sulfite: any salt of sulfurous acid. Often added to food or medication as a preservative.
Systemic: pertaining to or affecting the body as a whole.
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T.I.D.: three times a day. (Tris in Die)
Tourniquet: an instrument used to prevent the flow of blood to or from a distal area by its application around a limb. It could be as simple as a wide elasticized band used to slow systemic absorption of toxin following insect sting to an extremity.
Trachea: the tube descending from the larynx and branching into the two main bronchi.
Tracheostomy: the surgical creation of an opening into the trachea through the neck.
Tree Nut: a group of nuts which includes walnuts, cashews, almonds, hazelnuts, etc. Peanuts are not part of this group. They belong to the legume family.
Trigger: factors that bring on allergic symptoms, i.e. allergens.
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Urticaria: a vascular reaction of the skin marked by the transient appearance of smooth, slightly elevated patches (wheals) which are redder or paler than the surrounding skin and often attended by severe itching. Also called hives.
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Vascular: pertaining to blood vessels or indicative of a rich blood supply.
Vasoconstriction: diminution of the diameter of vessels, especially arterioles, leading to decreased blood flow to a part.
Vasodilation: widening (dilation) of a vessel, especially arterioles, leading to increased blood flow to a part.
Venom: a toxic substance normally secreted by a snake, insect or other animal.
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Wheal: a smooth, slightly elevated area on the body surface, which is redder or paler than the surrounding skin; it is often itchy and is the skin manifestation of allergy.
Wheeze: an abnormal whistling sound made in breathing, particularly in asthma.
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