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.





a substance which, when given with a drug or antigen, enhances its antigenicity (capacity to elicit an immune response) but does not evoke an immune response itself.

Adrenal gland: a paired set of organs located above the kidneys that produce epinephrine and other hormones.
Adrenaline: British name for epinephrine.
Adrenergic: activated or transmitted by epinephrine.
Aerochamber: a device used to facilitate the administration of inhalers.
Airway: the passage by which air enters and leaves the lungs. Also a tube used to maintain unobstructed breathing.
Albumin: a protein found in most animal and many plant tissues.
Allergen: a substance capable of inducing allergy or hypersensitivity. It is also the purified protein(s) used to test hypersensitivity.
Allergy: a hypersensitive state acquired through exposure to a particular allergen, reexposure bringing to light an altered capacity to react.
Ampoule: a small sealed glass vial containing medication for parenteral (non-oral) administration (e.g. epinephrine).
Ana-Kit™: the Ana-Kit® (Bayer) contains a pre-loaded syringe with two 0.30mg doses of epinephrine, 4 chewable 2 mg tablets of chlorpheniramine (antihistamine), 2 sterilizing alcohol swabs and a tourniquet (for the management of insect stings).
Anaphylactin : the antibody in anaphylaxis; it is formed after the first injection of foreign protein (antigen) and interacts with it on the second injection.
Anaphylactoid: a reaction similar to anaphylaxis in clinical presentation and treatment, but different in the chemical reaction that is taking place (e.g. exercise-induced anaphylaxis occurs via non-IgE mechanisms).
Anaphylaxis: exaggerated reaction of an organism to a foreign protein or other substance to which it has previously become sensitized.
Angioedema: recurring attacks of transient edema (swelling) suddenly appearing in areas of the skin or mucous membranes and occasionally of the viscera (internal organs); may be asymptomatic or associated with urticaria (hives) and redness.
Antibody: an immunoglobulin molecule with a specific amino acid sequence by which it interacts only with the antigen that induced its formation or antigen that is very similar to it.
Antigen: any substance capable of inducing antibody formation and of reacting specifically with the antibodies produced.
Antihistamine: a drug that counteracts the effects of histamine, a chemical that is released during allergic reactions.
Arrhythmia: variation from the normal rhythm of the heartbeat.
Arterial: from an artery, a blood vessel carrying oxygenated blood away from the heart.
Asthma: a condition marked by recurrent attacks of paroxysmal dyspnea (suddenly recurring episodes of laboured breathing), with wheezing due to spasmodic contraction of the bronchioles (small airways). In sensitized individuals, it is usually a manifestation of allergy.
Atopy: a clinical hypersensitivity (allergic) state with a hereditary predisposition; i.e., the tendency to develop an allergy is inherited, but the specific clinical form (hay fever, asthma, etc.) is not.
Auto-injector: a device used to administer/self-administer a predetermined/set dose of intramuscular or subcutaneous medication (e.g. Epipen®).
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Basophil: a white blood cell (leukocyte) which degranulates during anaphylaxis to release histamine and other mediators of hypersensitivity.
Beta-blockers: drugs that block one of the receptors for epinephrine and, hence, its effect. They are used to treat hypertension, angina, tremor and migraine.
B.I.D: twice daily. (Bis in Die)

systematic error introduced into sampling or testing by selecting or encouraging one outcome or answer over others. Researchers try to avoid bias through randomized controlled double blind trials.

Bioengineering: manipulation of genetic material to produce different strains (e.g. crops/food).
Biphasic: characterized by two distinct episodes.
Botanical Groups: foods that are members of the same family. Sometimes there can be cross sensitivity within a group (e.g. peanuts and other legumes).
Bronchi: (pl.) the larger passages conveying air to and within the lungs.
Bronchioles: the finer subdivisions of the air passages within the lungs.
Bronchodilation: a dilated (open) state of a bronchus.
Bronchodilator: an agent that causes dilatation (opening) of the bronchi.
Bronchospasm: spasmodic contraction of the smooth muscle coating of the bronchi which leads to narrowing, as occurs in asthma.
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CFIA: Canadian Food Inspection Agency.
Capillary: a tiny blood vessel that connects the venous and arterial blood vessels. This is the primary site of seepage during anaphylaxis.
Cardiovascular: pertaining to the heart and blood vessels.
Casein: the principle protein of milk.
Celiac disease: a condition characterized by hypersensitivity to gluten, a component of wheat.
Cell Mediated Immunity: acquired immunity in which the role of small lymphocytes of thymic origin predominate.
Challenge: when antigen is given intentionally to previously sensitized individuals in order to evoke and assess the allergic response.
Circulatory: pertaining to the circulation of blood.
Clinical: pertaining to or founded on actual observation and treatment of patients, rather than theory or basic science.
Complement: a complex series of enzymatic proteins found in normal serum that combine with antigen-antibody complex and produce injury as part of anaphylactoid reactions.
Complex: the combination of antigen and antibody.
Conjunctivitis: inflammation of the conjunctiva (the delicate membrane that lines the eyelids).
Contact dermatitis: an acute allergic inflammation of the skin caused by contact with various substances of a chemical, animal or vegetable nature to which hypersensitivity has been acquired. May also refer to a non-allergic reaction to a primary irritant.
Contrast medium: a dye used to enhance radiological images; often injected intravascularly.
Corticosteroid: any of the steroids produced by the adrenal cortex or their synthetic equivalents.
Cortisone: a hormone produced by the adrenal gland, which may also be administered to help control inflammation.
Cross contamination: the accidental deposition of a food ingredient in a product that does not normally contain it; this can happen through shared equipment or workers hands, etc.
Cross reactivity: allergic sensitivity to triggers that share similar or related structures; e.g. peanuts and other legumes.
Cyanosis: a bluish discoloration, usually referring to the skin and mucous membranes, due to an excessive amount of reduced hemoglobin in the blood (usually due to low oxygen levels which would follow difficulties with breathing or circulation).
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Delayed Reaction: refers to an anaphylactic reaction that follows contact with an allergen after a significant symptom-free period.
Dermatitis: inflammation of the skin.
Derma: the skin.
Desensitization: the process by which an individual is made less reactive (sensitive) to a specific antigen (trigger); e.g. insect sting desensitization.
Diagnosis: the art of distinguishing one disease from another.
Dosage: the determination and regulation of the size, frequency and number of doses (quantity to be given at one time).
Double blind: an experimental method by which both the subject and the experimenter are unaware of the nature of a given treatment; this design helps to avoid bias in experimental studies.
Dyspnea: difficult or laboured breathing.
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Eczema: a superficial, allergic, inflammatory process involving the skin; characterized acutely by redness, itching, oozing, crusting, and chronically by scaling, thickening, and discolouration.
Edema: demonstrable accumulation of excessive fluid in body tissues; often refers to fluid in the skin or lungs (pulmonary edema).
Empirical: based on experience, rather than scientific enquiry.
Enzyme: a protein capable of accelerating or producing chemical change in a specific substrate.
Eosinophil: a white blood cell that is involved in some allergic processes (asthma, allergic rhinitis and hay fever).
Epidemiology: the study of the relationships of factors that determine the frequency and distribution of disease.
Epidermis: the most superficial layer of skin.
Epinephrine: a hormone secreted by the adrenal gland that characterizes the "fight or flight" response to acute stress; it increases blood pressure, accelerates heart rate, opens the airways; it can also be administered to help control a severe allergic reaction.
Epipen®: an auto-injector that administers a fixed amount of epinephrine.
Erythema: redness of the skin.
Etiology: the study or theory of the factors that cause disease and their interaction with the host (patient).
Extract: a concentrated preparation of the protein of any substance to which a person may be sensitive (allergenic extract); used for diagnosis or desensitization therapy.
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Flare: the red outermost zone of a hive-like reaction; a manifestation of immediate hypersensitivity (allergy).
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Gangrene: death of tissue, usually following loss of blood supply.
Globulin: a class of proteins that are insoluble in water, but soluble in saline. See immunoglobulin.
Gluten: the protein of wheat and other grains which gives to dough its tough elastic character.
Ground Nut: peanut.
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Hapten: a non-protein substance that can evoke an immune response through combination with a carrier protein. On its own, however, it is not antigenic.
Histamine: a chemical present in many animal tissues, but particularly in the granules of mast cells and basophils. It is released during allergic reactions and dilates capillaries (causing vascular permeability and a drop in blood pressure) and causes bronchial constriction (closing of the airways).
Histology: the study of the minute structure, composition and function of tissue.
Hives: 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 severely itchy. Also called urticaria.
Hormone: a chemical, produced in the body by an organ, or cells of an organ, that has a specific effect on the activity of a target organ; e.g. epinephrine.
Humoral Immunity: acquired immunity in which circulating antibodies (immunoglobulins) play a key role.
Hydrolysis: the chemical process by which a compound is split into fragments by the addition of water.
HPP: hydrolyzed plant protein.
Hydrolysed Plant protein: protein of a plant source that has been fragmented by hydrolysis (usually corn, soy, wheat or peanut).
Hymenoptera: an order of insects usually having two pairs of well-developed membranous wings; includes bees, wasps, ants, etc.
Hypersensitivity: a state of altered immunological reactivity in which the body displays an exaggerated response to a foreign agent. Anaphylaxis is classified as a Type I immediate hypersensitivity reaction.
Hypotension: abnormally low blood pressure, as seen in shock.
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