What type of allergy testing directly measures the skin's reaction to allergens?

Skin prick testing is a method used to directly assess the skin's immediate response to specific allergens. During this test, small amounts of potential allergens are introduced into the skin through tiny pricks or scratches. The body's reaction, often swelling or redness at the site, indicates the presence of an allergy. This immediate hypersensitivity reaction is mediated by Immunoglobulin E (IgE), which is responsible for allergic reactions.

In contrast, blood tests, such as serum specific IgE tests, measure the levels of IgE antibodies in the blood rather than observing a direct reaction on the skin. Patch testing, on the other hand, is used primarily to identify delayed-type hypersensitivities, not immediate reactions. It assesses reactions to allergens over a longer period, typically 48 hours or more, by placing allergens on patches applied to the skin. Thus, skin prick testing is distinct in its ability to provide real-time results on allergic sensitivities through direct skin reactions.