gastrointestinal allergy

gastrointestinal allergy,

an immediate hypersensitivity reaction of the digestive system after the ingestion of certain foods or drugs. GI allergy differs from food allergy, which can affect other organ systems. Characteristic symptoms include itching and swelling of the mouth and oral passages, nausea, vomiting, diarrhea (sometimes containing blood), severe abdominal pain, and, in severe cases, anaphylactic shock. Treatment includes identification and removal of the allergen. In an acute attack epinephrine may be administered as a stimulant, and muscle relaxants may be given to reduce intestinal spasms that cause abdominal pain. In childhood, GI allergy is most often caused by hypersensitivity to cow's milk and is characterized by diarrhea and colicky pain, sometimes with vomiting, eczema, respiratory distress, and thrombocytopenia. Compare food allergy. See also lactose intolerance.

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allergy

an altered reactivity following second or subsequent exposure to antigen (allergen). See also hypersensitivity, allergic.

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atopic allergy

hereditary predisposition to develop certain allergies. See atopy.

bacterial allergy

a specific hypersensitivity to a particular bacterial antigen, e.g. Mycobacterium tuberculosis; it is dependent on previous infection with the specific organism.

bronchial allergy

asthma.

cold allergy

a condition manifested by local and systemic reactions, mediated by histamine, which is released from mast cells and basophils as a result of exposure to cold.

delayed allergy

see delayed hypersensitivity.

drug allergy

see drug allergy.

drying-off allergy

see milk allergy (below).

food allergy

called also gastrointestinal allergy; see food hypersensitivity.

gastrointestinal allergy

see food allergy (above).

hereditary allergy

an allergy with a hereditary predisposition. The tendency to develop some forms of allergy is inherited, but the specific clinical form is not. IgE, formerly called reagin or reaginic antibody, may be involved. See also atopy.

induced allergy

allergy resulting from the injection of an antigen, contact with an antigen, or infection with a microorganism, as contrasted with hereditary allergy.

inhaled allergy

see atopy.

milk allergy

a hypersensitivity to the milk protein, α-casein. Signs, varying from urticaria to anaphylaxis, have occurred in Jersey cows when milk escapes from the udder into the bloodstream during the drying off period.

physical allergy

a condition in which physical agents, such as heat, cold or light, trigger an allergic response.