In Reply Stevens-Johnson syndrome and toxic epidermal necrolysis are rare disorders. To study their recurrence over time, large data sets are needed. This precludes a case-by-case examination of medical records.
Dr Stern suggests that erythema multiforme and other less severe conditions may have been miscoded as Stevens-Johnson syndrome and toxic epidermal necrolysis. A 1995 study by Roujeau et al1 identified miscoding in 16% of cases.
Finkelstein Y, Macdonald EM, Juurlink DN. Recurrence of Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis—Reply. JAMA. 2014;312(15):1591. doi:10.1001/jama.2014.10783