Pityriasis versicolor.

The lipophilic yeast Pityrosporum ovale is both a member of the normal human cutaneous flora in adults and the etiological agent of pityriasis versicolor. Pityriasis versicolor develops under the influence of predisposing factors. The presence of these factors are also the reason for the high rate of recurrence seen in pityriasis versicolor and for its chronicity. There are numerous ways of treating pityriasis versicolor topically and systemically. Propylene glycol 50% in water is effective and cheap, but the imidazoles and the older antidandruff shampoos as well as two new antifungals: ciclopiroxolamine and terbinafine are also effective topically. However, short-term oral treatment with ketoconazole, itraconazole or fluconazole are very effective and the risk for side effects minimized with short treatment regiments. The patient compliance is also higher with oral treatment. The recurrence rate is very high, and to avoid this a prophylactic treatment schedule (eg, ketoconazole) one 200 mg tablet on three consecutive days every month or a single dose of 400 mg every month are effective.