Topical retinoids in inflammatory acne: A retrospective, investigator-blinded, vehicle-controlled, photographic assessment

Background: Despite published data showing the efficacy of topical retinoids in treating inflammatory acne, in clinical practice topical retinoids tend to be used most commonly for noninflammatory acne. Objective: The goal of this study was to assess theefficacy of topical retinoids as monotherapy in inflammatory acne. Methods: This retrospective, investigator-blinded,vehicle- controlled, photographic assessment study was conducted by 5 investigators. The investigators rated pretreatment and posttreatment photographs of patients who had participated in 12- or 15-week, double-blind comparisons of tazarotene 0.1% gel, adapalene 0.1% gel, tretinoin 0.1% microsponge, tretinoin 0.025% gel, and tazarotene 0.1% cream (vehicle). Acne severity was rated on a 7-point scale. A posttreatment increase or decrease of 1 grade was considered clinically meaningful; ≥2 grades was considered an even clearer measure of clinically significant improvement. Investigators also rated global response to treatment on a 7-point scale. A posttreatment increase of ≥2 grades was considered a clinically relevant improvement. Result: Each of the 5 investigators rated photographs of 577 patients (∼52% women, ∼48% men; mean age, 18-20 years), for a total of 2885 evaluations (in addition to daily evaluations of the 20 control patients). The treatment groups consisted of tazarotene (252 patients, 1260 evaluations), adapalene (178 patients, 890 evaluations), tretinoin microsponge (47 patients, 235 evaluations), tretinoin gel (39 patients, 195 evaluations), and vehicle (61 patients, 305 evaluations). Inflammatory acne was improved with all 4 retinoids compared with vehicle. In 1905 evaluations in which pretreatment acne severity was grade ≥3 (mild to moderate), the incidences of clinically significant improvements in the tazarotene, adapalene, and tretinoin microsponge groups were 24%, 17%, and 21%, respectively (all, P ≤ 0.001 vs vehicle [7%]). The difference in prevalence of clinically significant improvement was statistically similar between the tretinoin gel and vehicle groups. The incidences of clinically relevant improvement in global response to tazarotene, adapalene, tretinoin microsponge, and tretinoin gel were 36%, 34%, 31%, and 28%, respectively (P ≤ 0.001, ≤0.001, ≤0.001, and ≤0.01, respectively, vs vehicle [17%]). Conclusions: The results of this study suggest thattopical retinoid monotherapy can achieve clinically significant improvements in inflammatory acne.