[A double-blind placebo-controlled study of a 2 percent foaming lotion of ketoconazole in a single application in the treatment of pityriasis versicolor].

: A double-blind, placebo-controlled therapeutic trial of ketoconazole presented as a foam and applied only once was carried out on 61 patients by a group of 15 private dermatologists practising in the Paris region. All patients had tinea versicolor clinically diagnosed, then confirmed by a positive patch test, as assessed by a single mycologist. The main criterion of therapeutic effectiveness was negativation of the patch test 30 days after a single topical application of the ketoconazole foam. On day 30, the test was negative in 22 of the 28 patients in the ketoconazole group and in 5 of the 29 patients in the placebo (i.e. excipient) group (p less than 10(-5). Clinical and mycological cure was observed in only 11 of the 28 patients treated with the active substance, but among the 11 patients who still showed skin lesions despite a negative mycological examination 10 had achromic lesions which could be regarded as residual. This clearly indicates that the only criterion that can be used in a therapeutic trial on tinea versicolor is the mycological result. The active substance and the excipient were well tolerated; two patients in the ketoconazole group reported tingling of the skin at the site of application. We conclude that a single application of ketoconazole foam in effective and well tolerated in tinea versicolor. The single application technique unquestionably has advantages over repeated applications and should result in better patient's compliance and greater effectiveness in the long term.