A normally harmless substance that causes an allergic reaction (see allergy) in people who have become sensitized to it.
Allergens can include foods (for example, nuts, eggs, and shellfish); inhaled substances such as pollen, house dust, and fur; and some drugs.
Any substance – usually a protein – which, taken into the body, makes the body hypersensitive or ‘allergic’ to it. Thus, in hay fever, the allergen is pollen. (See ALLERGY.)
n. any *antigen that causes *allergy in a hypersensitive person. Allergens are diverse and affect different tissues and organs. Pollens, fur, feathers, mould, and dust may cause hay fever; house-dust mites (see Dermatophagoides) have been implicated in some forms of asthma; drugs, dyes, cosmetics, and a host of other chemicals can cause rashes and dermatitis; some food allergies may cause diarrhoea or constipation or simulate acute bacterial food poisoning. When a patient’s allergen has been identified (see patch test), it may be possible to attempt *desensitization to alleviate or prevent allergic attacks. —allergenic adj.
Some excipients used in the manufacture of tablets may have an allergenic effect. They may include additives, colourings, yeast, iodine, etc to which an increasing number of people are allergic. Present-day tablet-makers move away from these chemical binders and fillers, using natural alternatives such as vegetable oils, calcium phosphate, acacia gum and alginic acid from seaweeds. The term also refers to products, including herbal preparations made without sugar, starch, salt, wheat, yeast or artificial preservatives: suitable for vegetarians. ... hypo-allergenic
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