, molds, animal hair, dust mites and insect venom.The points under investigation are marked with a felt-tip pen. A drop of diluted allergen extract is then placed on the corresponding skin. This drop is crossed by a sterile lancet (a tiny pin), made to penetrate about 1 mm into the epidermis (prick in English means to prick). After one minute, the drop is removed with a piece of absorbent paper. After 15-30 minutes, the skin response to the prick test is observed. The test is considered positive if a wheal with a diameter equal to or greater than 3 mm appears, surrounded by an erythematous halo (redness), generally itchy.
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physiology diet-and-health blood-health
For the identification of skin allergies, such as nickel, the so-called patch test is used instead.
To ascertain the allergy, a drop of allergen extract that is suspected to be involved in the reaction is placed in contact with the skin and the area is then pricked with a special needle. If the person is allergic, the appearance of a characteristic wheal surrounded by an area of redness is observed.
The prick test is reliable, easily performed and completely painless.
or skin lesions there, and in younger children, the examination may be performed on the skin of the back.
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