East Asians exposed to the urate-lowering drug allopurinol have a predilection for severe cutaneous drug reactions such as drug-induced hypersensitivity syndrome or drug reaction with eosinophilia and systemic symptoms (DRESS) and Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN).
In opposite to the main cutaneous allergic drug reactions such as urticaria or maculopapular skin rash, in which antibiotics are the main culprits, in severe drug allergic reactions such as SJS (Stevens-Johnson Syndrome), TEN (Toxic Epidermal Necrolysis), or DRESS (Drug Reaction with Eosinophilia and Systemic Symptoms) Syndrome, compounds like allopurinol and anticonvulsants are the main causes.
Such T-cell-mediated adverse drug reactions such as Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN), drug-induced liver disease (DILI) and other drug hypersensitivity syndromes have more recently been shown to be mediated through interactions with various class I and II HLA alleles.
Among them, drug reaction with eosinophilia and systemic symptoms (DRESS) or drug-induced hypersensitivity syndrome (DIHS), Stevens-Johnson syndrome/ toxic epidermal necrolysis (SJS/TEN), are some of the most life-threatening severe cutaneous adverse reactions (SCARs).
To facilitate research in this area, we have set out standardized phenotypic definitions for (i) Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN), (ii) acute generalized exanthematous pustulosis (AGEP), and (iii) hypersensitivity syndrome (HSS; also known as drug reaction with eosinophilia and systemic symptoms (DRESS) and drug-induced hypersensitivity syndrome (DIHS)).