Efficacy and safety of permethrin 5% topical gel vs. placebo for rosacea: a double-blind randomized controlled clinical trial

Rosacea is a chronic, multifactorial, dermatological condition. Increased density of Demodex folliculorum mites in the skin of rosacea patients suggests a possible role for these mites in the pathophysiology of rosacea.

To evaluate the effects of permethrin 5% topical gel vs. placebo on Demodex density (Dd) and clinical presentations of rosacea patients, and also to further refine the quantitative assessment of Dd in the non-invasive standard skin surface biopsy (SSSB).

Twenty patients with bilateral papulopustular rosacea and ≥5 mites/cm² were enrolled in the study. Participants and physicians were blinded to the group assignments. Each patient applied permethrin on one side and placebo on the other side of the face twice daily for 12 weeks. SSSB and photography and Rosacea Clinical Scorecard of the National Rosacea Society were used to assess the patients at the baseline, 2nd, 5th, 8th, and 12th weeks for both sides of the face. Causality and severity of adverse drug reactions (ADRs) were assessed by WHO Scale and Hartwig Scale, respectively.

Dd was not significantly different between the two groups at the baseline. In both groups, Dd significantly decreased after 12 weeks compared to the baseline. At the end of the 12th week, the Dd in the permethrin group was significantly lower than the placebo group. Severity of the clinical presentations decreased in both groups at the end of week 12 in comparison to the baseline, particularly in the permethrin group. ADRs were all mild and in most cases unlikely related to permethrin.

Permethrin 5% gel can significantly reduce the Dd and severity of presentations in rosacea patients and can be a safe and effective option in the management of this chronic disorder. This new SSSB technique offers an easy, quick, inexpensive, and non-invasive sampling method proper for quantitative assessment of Dd.