Background: Lithium significantly improved seborrhoeic dermatitis symptoms in comparison with placebo. Objectives This randomized controlled trial was designed to show a non-inferiority of 15% (primary end-point) of lithium gluconate 8% ointment compared with ketoconazole 2% emulsion.
Methods: The study population comprised out-patients who had facial seborrhoeic dermatitis for at least 2 months, with moderate to severe erythema and desquamation at inclusion. The primary end-point was complete remission, defined as the disappearance of both erythema and desquamation. The non-inferiority of lithium was assessed on the 95% confidence interval (CI) of the difference between treatments.
Results: The intent-to-treat analysis (ITT) involved 288 patients and the per protocol (PP) analysis 269 patients. Treatment groups were comparable at baseline on age, sex, disease duration and symptoms. For the main criterion, the success rate was 52.0% (lithium) vs. 30.1% (ketoconazole) in the ITT population and 53.2% (lithium) vs. 30.7% (ketoconazole) in the PP population. The non-inferiority of lithium was demonstrated with differences of 21.9% (95% CI 10.0-33.7%) and 22.5% (95% CI 10.2-34.8%), respectively, in the ITT and PP population. As the lower limit of the 95% CI was > 0, the superiority of lithium was shown. Lithium also showed better results on other symptoms: burning and dryness. Adverse events were reported by 26.3% (lithium) and 25% (ketoconazole) of patients.
Conclusions: Lithium was 22% more effective than ketoconazole in giving complete remission of seborrhoeic dermatitis, with comparable safety.