Inappropriate medication use is associated with severe cutaneous adverse reactions (SCARs), according to findings of the RegiSCAR study published in the British Journal of Dermatology.

All cases of SCARs, including Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and drug reaction with eosinophilia and systemic symptoms (DRESS syndrome), reported to a French registry between 2003 and 2016 were reviewed with regard to three potential causes: inappropriate indication, unintentional re-use despite a previous allergic reaction, and self-medication with a prescription drug.

Of the 602 cases of SCARs included in the analysis, over 50% were associated with the use of allopurinol, antibacterials or antiepileptic drugs. Suspected drugs were considered to have been used appropriately used in 69.3% of patients. However, in 23.9% of patients they were inappropriately used, primarily due to prescriptions for inappropriate indications (65.8%) or unintentional rechallenge (20.9%). The drugs most frequently associated with inappropriate indications were allopurinol (51.9% of cases) and cotrimoxazole (13.5%). Antibacterial drugs were most frequently associated with unintentional rechallenge, while prescription nonsteroidal anti-inflammatory drugs were most frequently involved in inappropriate self-medication.

"Physicians should pay particular attention to adherence to accepted guidelines for the use of allopurinol and cotrimoxazole. All efforts to reduce unintentional rechallenge also seem to be necessary preventive measures," concluded the authors.