Pityriasis versicolor--epidemiological and therapeutical study.

Seventy-six patients with extensive pityriasis versicolor were divided into 3 groups and treated orally with ketoconazole, 200 mg daily, for 10, 20 or 30 days respectively. 50 patients out of this number completed the study. After 6 months, 46 patients were checked up. Eight of them developed relapses effectively treated with ketoconazole for another 15 days. Six out of these 8 patients belonged to the first group using ketoconazole for 20 days only. On the basis of this observation, we do not consider a 10 days' treatment to be sufficient and recommend that the patient should be treated for at least 20 days. As a preventive measure we recommend a daily bath with salicylic acid and sulphur soap. The frequency of the infection was higher in males (71.4%) than in females (28.6%). The youngest of the male patients was 4 months of age and the oldest 70 years. The youngest female was 4 months old and the oldest 50 years. Pityriasis versicolor was found to be predominant in the age group of 21--30 years. The sites most commonly involved were back, chest and the upper extremities.