Non-IgE-Mediated Drug Hypersensitivity Reactions.

PURPOSE OF REVIEW: Non-IgE-mediated drug reactions have traditionally been poorly defined and studied, though they are the most common form of hypersensitivity. Their presentations are highly variable and can range in severity from mild, cutaneous-only reactions to severe systemic disease. RECENT FINDINGS: The most notable advance in non-IgE-mediated hypersensitivity reactions is in diagnostics. HLA alleles have traditionally been used for identifying certain patients at risk for abacavir hypersensitivity syndrome, but more recent studies have shown several other HLA alleles associated with severe cutaneous adverse reactions with various medications. This article also highlights the use of delayed intradermal testing for radiocontrast media and patch testing for delayed antibiotic reactions. Drug reactions remain a major cause of morbidity and reason for treatment changes. Non-IgE-mediated reactions have had an increase in research interest over the past decade with an increased emphasis on better understanding the clinical presentation and underlying pathophysiology.