BACKGROUND: Severe cutaneous adverse reactions (SCARs) include Stevens-Johnson 
syndrome (SJS), toxic epidermal necrolysis (TEN), and drug reaction with 
eosinophilia and systemic symptoms (DRESS). SJS and TEN (SJS/TEN) and DRESS are 
thought to be different diseases; however, they share some clinical and 
laboratory features. Although SCORTEN serves as an excellent prognostic marker 
for SJS/TEN, there is still a need for development of other prognostic markers 
for SCARs.
METHODS: The study population consisted of 88 SCAR patients. Clinical 
characteristics and clinical manifestations were compared between SJS/TEN and 
DRESS. Risk factor analyses for prolonged hospitalization were performed.
RESULTS: Of the 88 patients, 41 were SJS/TEN and 47 were DRESS. Mortality rates 
of TEN and DRESS were 9.8 and 2.1%, respectively. Allopurinol and carbamazepine 
were the most common causes of both SJS/TEN and DRESS (34.7 and 62.9%, 
respectively). Some of the systemic presentations, such as fever and laboratory 
abnormalities were common in both phenotypes. Thrombocytopenia tended to be 
related to prolonged hospitalization (longer than 3 weeks) in SJS/TEN (odds 
ratio, OR = 5.1, 95% confidence interval, CI 0.8-31.8, p = 0.076). In DRESS 
patients, leukocytosis at presentation (OR 4.8, 95% CI 1.1-20.3, p = 0.03) was 
related to prolonged hospitalization.
CONCLUSIONS: Clinical features of SCARs in a tertiary hospital in Korea were 
similar to those reported previously. SJS/TEN and DRESS shared some clinical and 
laboratory features. Thrombocytopenia for SJS/TEN and leukocytosis at 
presentation for DRESS may be useful prognostic markers for prolonged 
hospitalization.