Previous studies have supported the role of yeast as a causal factor in seborrheic dermatitis due to the observed benefits with antifungal treatments. However, the connection betweenyeast from the Malassezia species and seborrheic dermatitis is controversial. A review in the Cochrane Library examined existing data from randomized controlled trials on the use of topical antifungals for seborrheic dermatitis in adolescents and adults, with primary outcome measures of complete clearance of symptoms.
The review included 12 trials on ketoconazole, 11 on ciclopirox, two on lithium, two on bifonazole, and one on clotrimazole; all treatments were compared to placebo or vehicle for efficacy. Nine ketoconazole trials and one miconazole trial compared these treatments to steroids; Fourteen studies compared one antifungal to another or different doses or schedules of administration of the same agent vs. one another.
Topical ketoconazole 2% treatment had a 31% lower risk of failed clearance of rashes vs. placebo at four weeks follow-up, but the evidence was of very low quality, which may have had an effect on reported adverse events. Ketoconazole therapy led to a remission rate similar to steroids (low quality evidence), but side effects were reduced by 44% in the ketoconazole group vs. the steroid arm (moderate-quality evidence). Ketoconozale had a similar remission failure rate as ciclopirox in three trials (low-quality evidence). The majority of comparisons between ketoconazole and other antifungals were based on single studies with comparability of treatment effects observed.
Ciclopirox 1% had a lower failed remission rate vs. placebo at four weeks follow-up with similar rates of side effects (moderate-quality evidence).
Clotrimazole and miconazole efficacies were comparable with steroids in single study short-term assessments. The effects on individual symptoms were less clear and inconsistent.There was insufficient evidence to conclude that dose or delivery mode impacted treatment outcomes. One small study in patients with HIV compared the effect of lithium compared to placebo on seborrheic dermatitis of the face with similar treatment outcomes.
Although ketoconazole and ciclopirox were found to be more effective than placebo, there is limited evidence that either is more effective than another agent within the same class. Most of the studies were short-term (less than four weeks). Improved outcome measures, including quality of life, are needed for additional research on antifungals for seborrheic dermatitis.