Split-Face Clinical and Bio-Instrumental Comparison of 0.1% Adapalene and 0.05% Tretinoin in Facial Acne

BACKGROUND: Adapalene and tretinoin are topical compounds active for treating acne. OBJECTIVE: To compare the efficacity and safety of adapalene 0.1% gel and tretinoin 0.05% gel in moderately severe facial acne using clinical and objective biometrological assessments. Such information is currently lacking in the literature. METHODS: The split-face method was used in 25 acne volunteers for a 6-week treatment. In addition to clinical counts of lesions, the amount of comedones was assessed using computer-assisted morphometry of cyanoacrylate follicular biopsies. The erythema index and squamometry values were used to quantitate skin irritation. RESULTS: The tretinoin formulation brought better comedolysis and clinical improvement than the adapalene formulation. Erythema was transiently more pronounced on the tretinoin-treated side. Squamometry yielded no significant difference between both products. CONCLUSION: Tretinoin 0.05% gel exhibits a greater anti-acne efficacy than adapalene 0.1% gel, although with temperate tolerability.