Testing for food allergy does not differ significantly from testing for inhalant allergens such as pollen. Besides testing different foodstuff, the prick to prick test with fresh food is occasionally used to augment the testing panel. In order to differentiate food allergy from a possible food intolerance, further testing for food intolerance is sometimes indicated (e.g. H2 testing for lactose intolerance).
In contrast to testing for inhalant allergens, in case of suspected insect venom allergy, a blood sample is taken in the first place to assess specific IgE against the insect venom. Skin testing is performed afterwards on a second occasion. Due to safety reasons, we test step by step with increasing concentrations of venom. Therefore, the test may last up to 2 hours. Asthmatics have to do a lung function test prior testing. We never ever use life insects to sting you, neither for testing nor for assessing treatment outcome after specific immunotherapy. However, we always test for both bee and wasp venom.
In case of suspected drug allergy, a blood sample is taken to assess specific IgE (as far as available/applicable) against the certain drug. Skin testing is performed step by step with increasing concentrations of drug on a second occasion. Beside skin prick testing, the intracutaneous test is used due to its higher sensitivity. In case of unclear results or in case of drugs we cannot test, a specific provocation performed in a hospital is recommended.
In testing for contact dermatitis special patches are used to apply small amounts of potential contact allergens on the skin of the back. These patches have to be in place for at least 2 days. In order not to dislocate the patches or make to allergens merge, no sports are recommended during testing. In addition, you must not shower the back with the patches on. On day 3, reading is done. A positive reaction is characterized by erythema, swelling and small vesicles at the testing site. Beside the standard block, there is a wide testing panel of different substances. Sometimes, skin care products such as emollients, sun tan creams or cosmetics can be tested on the skin as they are.