Toxic epidermal necrolysis and Steven Johnson syndrome in Sri Lanka; clinical course, HLA-B*1502 allele and its association to carbamazepine

Steven Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) occur frequently with carbamazepine among the carriers of HLA-B*1502 allele. The study evaluated the clinical course and strength of this association in Sri Lanka.
Twenty four consecutive patients with SJS/TEN from multiple dermatology centres were assessed for demographics, history and clinical course. Carbamazepine induced cases with a group of healthy control (10) were tested for HLA-B*1502 using multiplex PCR with sequence specific primers.
The sample had a mean age of 41.6 years; female: male ratio of 3:1. Antiepileptics were the aetiological cause in 12 (50%), amongst 9 (37.5%) taken carbamazepine. The HLA-B*1502 allele was positive only in one patient but none in the control group (10). The mucosal involvement was common (95.8%).
Carbamazepine is the commonest single therapeutic agent implicated in SJS/TEN, although the association with the HLA-B*1502 allele is weak in our sample. Early mucosal involvement is a reliable clinical sign useful for the diagnosis.