A 10-years retrospective study on Severe Cutaneous Adverse Reactions (SCARs) in a tertiary hospital in Penang, Malaysia.

Introduction: Severe cutaneous adverse drug reactions (SCARs) are not uncommon and potentially lifethreatening. Our objective is to study the patient characteristics, the pattern of implicated drugs and treatment outcome among patients with SCARs.
Methods: A 10-year retrospective analysis of SCARs cases in Penang General Hospital was carried out from January 2006 to December 2015. Data collection is based on the Malaysian Adverse Drug Reactions Advisory Committee registry and dermatology clinic records.
Results: A total of 189 cases of SCARs were encountered (F:M ratio; 1.2:1.0; mean age of 45 year). The commonest manifestation was Stevens-Johnson Syndrome [SJS] (55.0%), followed by toxic epidermal necrolysis [TEN] (23.8%), drug rash with eosinophilia and systemic symptoms [DRESS] (12.7%), acute generalised exanthematous pustulosis [AGEP] (4.8%), SJS/TEN overlap syndrome (2.6%) and generalised bullous fixed drug eruptions [GBFDE] (1.1%). Mean time to onset for TEN/SJS/Overlap syndrome was 10.5±13 days; AGEP, three days; GBFDE, 2.5±0.7 days, and DRESS, 29.4±5.7 days. The most common drugs implicated were antibiotics (33.3%), followed by allopurinol (18.9%) and anticonvulsant (18.4%). Out of 154 cases of SJS/TEN/overlap syndrome, allopurinol was the commonest causative agents (20.1%). In DRESS, allopurinol accounts for 45.8% of the cases. The mortality rate in SJS, TEN and DRESS were 1.9%, 13.3% and 12.5% respectively. No mortality was observed in AGEP and GBFDE.
Conclusion: The commonest manifestations of SCARs in our setting were SJS, TEN and DRESS. Allopurinol was the most common culprit. Thus, judicious allopurinol use is advocated and pre-emptive genetic screening for HLAB *5801 should be considered.