Allergy Diagnosis

Methods for the diagnosis and assessment of allergies:

Skin prick test

Prick test is the most typical method of allergic diseases diagnosis and control. Small amounts of various allergens are either put in contact with scratchings made into the skin of the patient, or intradermally injected. Each of the test spots is marked with a pen (so the doctor knows which allergen was injected in which scratch). Within 30 minutes from the contact, if the patient is allergic, an inflammatory reaction occurs. The reaction can vary from a small red spot on the skin to large hives. The bigger is the reaction, the more allergic is the patient to the respective substance.
The skin prick test is simple, cheap and relatively accurate. Yet, it can be wrong if the patient had previously ingested antihistamines, which did not have enough time to be eliminated from the body, thus acting like a mask and diminishing the allergen contact reaction.
Skin prick tests for food allergens are very accurate if the result is negative. If the result is positive, the tests must be correlated with elimination diets and clinical history of the patient.
Good allergy care should start with choosing an allergy and immunology specialist.

RAST tests (Total IgE count)

Another method used to diagnose allergies is measuring the amount of IgE antibodies contained within the patient’s serum. This can be determined through radiometry and colorimetric analysis. RAST (the radioallergosorbent test) can determine even the levels of IgE antibodies specific to certain allergens.

In severe cases, prick tests can be very dangerous, as the patient’s immune system can react violently, causing anaphylaxis, edema, or coma. This is why, if severe allergic reactions to certain allergens are suspected, RAST tests are preferred.