Randomized, Triple-Blind, Placebo-Controlled Trial of Topical Dapsone Gel in Patients With Acne Vulgaris

Overview

The goal of this randomized, double-blind, placebo-controlled clinical trial is to learn whether topical 7.5% dapsone gel is effective for treating acne vulgaris in adults. The main questions are: * Does dapsone gel reduce the number and severity of acne lesions compared with a placebo (vehicle) gel? * Does dapsone gel improve skin redness (erythema) and pigmentation (melanin) measured with a Mexameter, and reduce skin oiliness (sebum) measured with a Sebumeter? * Does treatment with dapsone gel improve patients' quality of life? Researchers will compare once-daily dapsone gel with a look-alike placebo gel (no active ingredient). What participants will do: * Apply either dapsone gel or placebo gel once daily for 8 weeks * Attend clinic visits at baseline (start), week 4, and week 8 * Have acne lesions counted and graded at each visit * Have erythema and melanin measured with a Mexameter, and sebum measured with a Sebumeter at predefined facial sites (both cheeks and the glabella) * Complete a quality-of-life questionnaire at baseline and week 8 * Have standardized photographs taken at each visit

This is a prospective, randomized, double-blind, placebo-controlled clinical trial designed to evaluate the clinical efficacy of topical 7.5% dapsone gel in the treatment of acne vulgaris. The study will also investigate effects on skin biophysical parameters using standardized instruments: erythema and melanin with a Mexameter, and sebum production with a Sebumeter. Two parallel arms will be included: one group will apply 7.5% dapsone gel once daily, and the other will apply a vehicle (placebo) gel identical in appearance and packaging but without the active ingredient. Randomization will be computer-generated, and both investigators and participants will remain blinded to treatment allocation. Participants will attend clinic visits at baseline (Day 0), Week 4, and Week 8. At each visit, standardized digital photographs will be taken, and lesion counts will be performed. Lesion assessments will include comedonal and papulopustular counts according to Plewig \& Kligman, the Global Acne Grading System (GAGS), and the Investigator's Global Assessment (IGA). At each visit, Mexameter readings (erythema and melanin) and Sebumeter readings (sebum) will be obtained at three predefined facial sites (right cheek, left cheek, glabella/forehead) using triplicate measurements after a standardized acclimatization period. The Acne Quality of Life Index will be administered at baseline and Week 8. Treatment with dapsone or placebo will continue for 8 weeks, after which the study ends for both arms. Following completion at Week 8, participants may initiate standard acne therapies as clinically indicated outside the study. The primary focus is to determine whether dapsone gel significantly reduces inflammatory lesion counts compared with placebo at Week 8. Secondary evaluations include changes in comedonal lesion counts, acne severity scores (GAGS and IGA), erythema and melanin indices (Mexameter), sebum levels (Sebumeter), and patient-reported quality of life (Acne-QoL). By combining standardized clinical assessments, validated scoring systems, patient-reported outcomes, and objective biophysical measurements, this trial aims to generate robust evidence regarding the effectiveness of topical 7.5% dapsone in acne management.