Seasonal variation of Stevens-Johnson syndrome and toxic epidermal necrolysis associated with trimethoprim-sulfamethoxazole

Background Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are rare and severe cutaneous adverse reactions to medications and infections. Objective We sought to determine whether a seasonal variation to SJS and TEN exists and to define the characteristics in our tertiary referral hospital. Methods A retrospective chart review of 50 patients from 1995 through 2007 was performed and statistically analyzed. Results The most common medication implicated as a cause of SJS/TEN was trimethoprim-sulfamethoxazole (TMX) (26%). A seasonal trend, favoring springtime, was observed for the total number of cases of SJS and TEN ( P = .34). There was a significant increase in cases due to TMX (53%) occurring in spring compared to other seasons ( P = .002). These patients were significantly younger (37.8 ± 13.7) than other patients with SJS and TEN (53.7 ± 16.4) ( P = .003). Their overall mortality (1 death) and average SCORTEN value (1.62 ± 1.6) was also significantly lower ( P = .04 and 0.03, respectively). Based on outpatient pharmacy records, there was no increase in TMX prescriptions filled during the spring. Limitations The study was limited by reliance on chart data, the use of inpatient records, and number of patients. Conclusions A seasonal variation in SJS and TEN caused by TMX affecting younger patients may exist.