The first step is to see your doctor. An experienced GP, paediatrician or an allergy specialist will take a history of reactions, examine you and possibly arrange for allergy tests.
What are the tools of diagnosis?
Skin prick tests or blood (RAST or Cap RAST) tests can be performed to help diagnose allergies – either by observing reactions on the skin or by measuring the amount of IgE antibody produced to a specific allergen in the blood.
These tests are often used to confirm a diagnosis of suspected allergy, and results need to be interpreted by an experienced doctor or allergy specialist. Negative reactions may indicate a different type of allergic response. You should also be aware that a positive result does not necessarily mean you will react to that food. Again, a history of reactions is the first step in diagnosing allergies.
Skin prick tests maybe carried out on infants as young as three months old, although their skin may not be as reactive, which may affect test results. They are reliable and painless tests involving small drops of the “allergen” being placed onto the forearm or back, then the skin is pricked to allow a tiny amount of the allergen into the skin. Reactions are then measured and reported to, or observed, by the doctor.
In the case of food allergy, your doctor may advise you to keep a food diary to help in the identification of food allergy. A food and symptom diary can be a very helpful tool for you too. You may wish to consider starting one before you see the allergy specialist or GP so you have a written record of diet and reactions for you first visit. Over a period of a week or two, a pattern may emerge. It is important to note that if reactions to a particular food are obvious, avoid that food in question until you have consulted your doctor.
Food allergy testing
Other tests are available to diagnose skin contact allergies, so ask your doctor.