Prick test | Food allergy testing

Prick test

The prick test is a skin test that is used to detect various forms of allergy. It is used for example to detect contact allergies, hay fever or animal hair allergies. Even if this may seem paradoxical at first glance, since it is applied on the skin, the prick test is also used in the diagnosis of food allergies.

The basic principle of the prick test is that certain potentially allergenic substances are applied to the skin of the patient’s forearm. They are then inserted with a small needle into the uppermost layer of skin. After usually a maximum of 60 minutes, the skin is examined for rashes or irritations.

If such an irritation is found, this is an indication that the allergen previously applied there has indeed triggered an allergic reaction in the body. While there are standardized test substances that are applied to the skin in the prick test for suspected contact or respiratory allergies, this is not always the case for suspected food allergies. This complicates the testing for food allergies using the prick test to some extent.

If there is no industrial test substance for the food to be tested, a so-called prick-to-prick test is used. First, the needle is used to absorb some of the allergen to be tested, then the needle is pricked into the uppermost layer of skin. Before the prick test is carried out, the patient’s medical history is taken.

The treating dermatologist will try to narrow down the allergic reaction of the body by asking specific questions. In order to simplify the anamnesis, it is therefore advisable that the affected person keeps a dietary diary in the weeks before the prick test so that it becomes clear after which foods allergic reactions occurred.Only these foods are then used for the prick test. If there is no indication as to which food is the potential allergen, the most important and common foods should be used as test substances for the prick test.