Diagnosing allergies

Diagnosing food allergies relies on a careful medical history, examination and special allergy tests. Your doctor will ask you about the symptoms of the reaction, whether they have happened every time the food has been eaten and how long they took to appear. With immediate type allergies, testing can be done by a blood test or by a ‘skin prick’ test, where food extracts are placed on the skin of the arm and gently pricked. The results of either test can be very helpful in confirming if the allergy is present. Unfortunately, with delayed allergies, things are less straightforward as there are not any reliable straightforward tests.

However, careful exclusion diets, where the suspected food is completely taken out of the diet may be recommended with the assistance of an experienced dietician. If the food is the cause of the symptoms then they should improve when the food is withdrawn. This exclusion period should be followed by reintroduction of the food to ensure than any improvement really was due to the food being removed. If the symptoms are relieved on exclusion and return on reintroduction then a diagnosis can be reached.