The SCORTEN, calculated within 24 hours of admission, is a severity-of-illness score validated for toxic epidermal necrolysis and Stevens-Johnson syndrome. Our purpose was to assess the performance of successive SCORTEN during the first 5 days of hospitalization and to determine the influence of admission delay. Charts of 144 patients aged 46.8 years (+/-19.7), admitted to our department (1993-2003) with Stevens-Johnson syndrome or toxic epidermal necrolysis, were reviewed. Successive SCORTEN were compared between deceased patients (n = 28, 19.4%) and survivors (n = 116). The performance of the score (calibration, discrimination) was assessed on days 1-5. All seven SCORTEN variables, on days 1-5, were associated with a higher mortality rate. The SCORTEN rose slightly during hospitalization, with a significant difference between days 1 and 4 (<0.05). Performance of the SCORTEN was good on each day, but slightly better on day 3. The areas under the receiver-operating characteristic curves were above 80%. The admission delay did not differ between deceased patients and survivors. Delay-adjusted SCORTEN was close to the crude SCORTEN. The SCORTEN performance during the first 5 days of hospitalization was excellent, and at its best on day 3. We recommend to compute again the SCORTEN on day 3. The admission delay did not influence prognosis or SCORTEN.