Allopurinol, the most used urate-lowering drug for the treatment of gout, is associated with rare but life-threatening severe cutaneous adverse reactions (SCARs) such as Stevens–Johnson Syndrome (SJS), Toxic Epidermal Necrolysis (TEN), and Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) syndrome, but not Acute Generalised Exanthematous Pustulosis (AGEP). They are characterised by severe skin and systemic involvement and are associated with substantial morbidity and a high risk of mortality. This narrative review summarises evidence on the clinical presentation, epidemiology, risk factors, and preventive strategies for allopurinol-induced SCARs. Key risk factors include the presence of the HLA-B*58:01 allele, renal impairment, older age, female sex, heart disease, higher starting doses of allopurinol, and certain ethnicities, e.g., South Asian, Han Chinese, and African populations likely due to the higher prevalence of the HLA-B*58:01 allele. Risk mitigation strategies include genetic testing for HLA-B*58:01 in high-risk ethnic groups and avoiding allopurinol in those that are positive for the HLA-B*58:01 allele, starting allopurinol at a low-dose (e.g., 50–100 mg/day) and up-titrating it gradually at 4-week intervals, and avoiding high-dose allopurinol in those with risk factors (e.g., chronic kidney disease stage ≥3). In addition, risk stratification using prediction tools may enable a safer use of allopurinol.
Cipolletta et al. (Fri,) studied this question.