The clinical efficacy of oral isotretinoin in the treatment of severe acne is well established but there is no published data about the recurrence rate and the optimum dose for lowest recurrence in Korean patients.

The objective of this study was to determine the recurrence rate after one course of isotretinoin in oriental cases.

Sixty eight cases were available which fulfilled the inclusion criteria ; clearing af- l ter one course more than 10 weeks and at least two year follow-up thereafter. Isotretinoin was used with oral dosage 0.3-1 mg/kg/day (0.6±0.1) with duration from 10 to 46 weeks (19.7±6.2).

Overall, 78% of patients had relapsed with most requiring topical antibiotic therapy only. In patients receiving more than 120 mg/kg, the percentage without recurrence was 75 % which was significantly higher (p<0.001) in comparison with only 15 % among patients receiving less than 120 mg/kg. Doses between 100 and 120 mg/kg were not as effective as those ones with more than 120 mg/kg for preventing recurrence.

The results indicate that moderate doses of isotretinoin are well tolerated and pro-duce excellent clearing. However, in order to minimize recurrence rate, the optimum dose may be at least over 120 mg/kg of the cumulative dose which means more than 6 months of treatment in most of the Korean patients with acne.