Skin testing set for allergies, 1871-1930.
© Science Museum / Science & Society Picture Library
Made by Duncan Flockhart & Co. In skin testing, small amounts of various substances to which a patient may be allergic are put onto separate places on the skin's surface or injected into the skin. It is then posible to determine which substance is responsible for the allergy by seeing which of the treated areas shows a reaction, normally rednes or inflammation. Skin testing is regarded as a quick, reliable and economical way of diagnosing allergies.