Retinoids and Azelaic Acid to Treat Acne and Hyperpigmentation in Skin of Color

using the Cochran–Mantel–Haenszel test. Results showed that there were no statistically significant differences in dryness, scaling, and burning with the ADA/BPO protocol in subjects with Fitzpatrick skin types I to III compared with subjects with Fitzpatrick skin types IV to VI.⁴ The erythema of patients with Fitzpatrick skin types IV to VI was rated as “none” more often than that of patients with Fitzpatrick skin types I to III (P<.001). This could be due to the difficulty in visualizing erythema in patients with darker skin types, particularly Fitzpatrick skin type VI. The analysis established that acne patients with Fitzpatrick skin types IV to VI were not more susceptible to cutaneous irritation from treatment with the ADA/BPO gel when compared with patients with Fitzpatrick skin types I to III.⁴

Tazarotene vs Adapalene for Postinflammatory Hyperpigmentation

In a 40-week, blinded, vehicle-controlled trial, 68 African American subjects with hyperpigmentation due to acne, folliculitis, eczema, and shaving irritation were treated with either topical tretinoin 0.1% cream or vehicle applied to face and arms.⁶ Investigators assessed both the hyperpigmented skin as well as the normal skin. The designated lesions of PIH and normal skin were assessed with a colorimeter (Chroma Meter CR-200; Minolta Camera, Osaka, Japan) before treatment and after 12, 24, and 40 weeks of therapy.⁶ The reduction in hyperpigmentation observed at 4 weeks with tretinoin vs at 24 weeks with vehicle was statistically significant.⁶ Assessing the normal skin, no significant lightening was observed clinically; however, mild skin lightening could be observed via colorimetry.⁶

In a community-based trial comparing 3 different topical therapeutic regimens, one subset analysis looked at pigmentary changes with acne cases in skin of color. All patients received combination clindamycin 1%/BPO 5% topical gel containing glycerin and dimethicone. Subjects were randomized to receive this combination therapy in addition to either a tretinoin microsphere gel at concentrations of either 0.04% or 0.1%, or ADA gel 0.1%. Hyperpigmentation was assessed using a subjective 5-point scale, where 0 = absent, 1 = slight, 2 = mild, 3 = moderate, and 4 = severe. Hyperpigmentation in those subjects receiving the clindamycin/BPO topical gel in combination with tretinoin gel 0.04% trended toward better resolution when compared with the ADA gel.⁷

To assess efficacy and the safety of a topical gel containing clindamycin 1.2% and tretinoin 0.025% in acne and acne-induced PIH in darker-skinned patients, researchers undertook a randomized, double-blind, placebo-controlled study of 33 patients with Fitzpatrick skin types IV to VI.8 Efficacy was measured using the evaluator’s global acne severity scale, lesion counts, PIH severity scales (from 0 = normal to 8 = severe), and patient’s global assessment scale. Safety and tolerability were assessed using adverse event reports and a safety assessment scale.⁸

After 12 weeks of therapy, the mean inflammatory lesion count was 11.⁹ in clindamycin/tretinoin-treated patients compared with the baseline count of 17.4. In the placebo group, the mean inflammatory lesion count went from 17.7 to 13.6 (P=.05).⁸ All patients had baseline PIH severity scale scores ≥2, and a substantial proportion had scores of 3 or 4 in the clindamycin/tretinoin gel (70%) and placebo groups (69%).8 The improvement in mean PIH score from baseline to week 12 was greater for clindamycin/tretinoin gel vs placebo (–1.2 vs –0.9), and this small improvement was consistent throughout the trial. The number of patients with ≥2-point improvements in PIH scores was similar between the clindamycin/tretinoin gel group and the placebo group (33%).8 The results of this pilot study suggest clindamycin phosphate 1.2%/tretinoin 0.025% topical gel is safe and effective option for treating mild to moderate acne and PIH in patients with skin of color.⁸

Azelaic acid (AzA) is a dicarboxylic acid from Pityrosporum ovale that inhibits tyrosinase and has cytotoxic and antiproliferative effects. A 15% gel and 20% cream are commercially available. Studies have found this agent useful in treating hyperpigmentation with acne.⁹ A 16-week, baseline-controlled study of patients with Fitzpatrick skin types IV to VI evaluated the efficacy of topical AzA gel 15% applied twice daily (n=20). Assessments at baseline and each visit included IGA of acne on