ABSTRACT
Hypersensitivity reactions to drugs are classified as immediate or nonimmediate reactions depending on the basis of time of appearance of reactions. Clinical and immunological studies suggest that immediate reaction is IgE-mediated and nonimmediate as type-IV (cell-mediated) reaction. For the evaluation of drug allergy, the patient's history is fundamental; the allergologic examination includes in-vivo and in-vitro tests selected on the basis of the clinical features. Prick, patch, and intradermal tests are the most readily available forms of allergy testing. However, there are some changes in the diagnostic evaluation of allergic reactions to beta-lactams, iodinated contrast media and local anaesthetics over the last several years. In immediate reactions, the sensitivity of skin testing and immunoassay is decreasing and for nonimmediated reactions, skin testing appears to be less sensitive than previous results. Drug provocation test is still the gold standard for identification of an causative drugs. The new diagnostic tools, such as the basophil activation test and the lymphocyte activation test, have been developed and are under validation. Based on the literature, the proposed algorithm may safely and rapidly distinguish between immediate-type and immediate drug reactions. This review provides an update to European Network for Drug Allergy (ENDA) document that gave the guidelines for the evaluation of drug allergy. The diagnosis of drug allergy needs to be standardized.
