Efficacy and safety of topical isobutylamido thiazolyl resorcinol (Thiamidol) vs. 4% hydroquinone cream for facial melasma: an evaluator-blinded, randomized controlled trial.

BACKGROUND: Melasma can be refractory to treatment, and relapses are frequent. Thiamidol is a new potent tyrosinase inhibitor that has been found effective as a cosmeceutical for the depigmenting of melasma. OBJECTIVE: This study compared the efficacy and tolerability of topical 0.2% Thiamidol vs. 4% hydroquinone for facial melasma. METHODS: Fifty women with facial melasma participated in a randomized, evaluator-blinded, controlled study from September through November 2020. Patients were randomly assigned to apply a double layer of 0.2% Thiamidol twice a day or 4% hydroquinone cream at bedtime, for 90 days. Both groups received tinted sunscreen (sun protection factor 60, PPD 20). The primary outcome was the change from the baseline Modified Melasma Area Seve:rity Index (mMASI) score. Secondary outcomes were improvements in the patients' quality of life [Melasma Quality of Life Index (MELASQoL)], colourimetry, and Global Aesthetic Improvement Scale (GAIS) evaluation. RESULTS: One participant, from the hydroquinone group, did not complete the study (unrelated to adverse effects). The mean (SD) age of the participants was 43 (6) years, and 86% were phototypes III-IV. Both groups exhibited a reduction in mMASI, MELASQoL, and colour contrast scores (P < 0.01). The mean [95% confidence interval (CI 95%)] reductions of the mMASI scores were 43% (35-50%) for Thiamidol and 33% (23-42%) for hydroquinone. There was no difference between the groups in the reductions in mMASI, MELASQoL, colourimetric contrast and GAIS scores (P ≥ 0.09). The GAIS analysis resulted in an improvement of 84% (CI: 95% 67-97%) for participants in the Thiamidol group and 74% (CI: 95% 61-93%) for those in the hydroquinone group. There were only mild adverse effects in the Thiamidol group, but allergic contact dermatitis was evidenced in two (8%) participants. CONCLUSION: The melasma improvement achieved using 0.2% Thiamidol did not differ from that of 4% hydroquinone cream. Thiamidol can be considered a suitable option for melasma patients with poor tolerability or treatment failure with hydroquinone.

French maritime pine bark extract (pycnogenol) in association with triple combination cream for the treatment of facial melasma in women: a double-blind, randomized, placebo-controlled trial.

BACKGROUND: Melasma can be recalcitrant to treatment, and relapses are common. Pycnogenol has been reported to be effective in treating melasma. OBJECTIVE: To compare the efficacy, safety and tolerability of 75 mg pycnogenol taken orally twice a day vs. a placebo, in association with the triple combination and broad-spectrum sunscreen for the treatment of facial melasma. METHODS: A randomized, double-blind, parallel, placebo-controlled study was conducted on 44 women with facial melasma in a single centre from May 2019 through November 2019. Patients with melasma were randomly assigned to orally take 75 mg pycnogenol (PYC) or a placebo (PLAC) twice a day for 60 days. Both groups also received tinted sunscreen [Sun Protection Factor (SPF) 50; Persistent Pigment Darkening (PPD) 17] for daytime use and a topical triple combination at bedtime. The primary outcome was a change from the baseline Modified Melasma Area Severity Index (mMASI) score. Secondary outcomes were improvements in the patients' quality of life (MELASQoL), colorimetric indices and Global Aesthetic Improvement Scale (GAIS). RESULTS: All participants completed the trial. The mean (SD) age of the participants was 39 (7) years, and 91% were phototypes III-IV. Both groups exhibited a reduction in mMASI scores, MELASQoL scores and colour contrast (P < 0.01). The mean (CI 95%) reductions of the mMASI scores were 49% (36-61%) for PYC and 34% (16-47%) for PLAC. The reductions in mMASI scores and colorimetric contrast were superior for the PYC group (P < 0.05). The analysis of GAIS resulted in an improvement of 86% (CI 95%: 68-96%) for the participants in the PYC group and 55% (CI 95%: 32-73%) for those in the PLAC group. There were no adverse effects related to oral treatment. CONCLUSION: Pycnogenol is well-tolerated and increases the effectiveness of broad-spectrum sunscreen and the triple combination in the treatment of facial melasma in women.

Exploring pathways for sustained melanogenesis in facial melasma: an immunofluorescence study.

BACKGROUND: The physiopathology of epidermal hypermelanization in melasma is not completely understood. Several cytokines and growth factors are increased in skin with melasma, nevertheless, nor the pathways involved in the increased αMSH expression have been adequately evaluated, nor a model for sustained focal melanogenesis is available. OBJECTIVE: To explore stimulatory pathways for epidermal pigmentation in facial melasma related to αMSH: those linked to ultraviolet radiation, oxidative stress, inflammation, neural crest pigmentation cell differentiation and antagonism of αMSH. METHODS: Paired skin biopsies (3 mm) from 26 women with facial melasma and from normal adjacent skin (<2 cm far) were processed for immunofluorescence with markers for p53, p38, αMSH, MC1R, Melan-A, IL-1α, COX2, Wnt1, WIF-1 and ASIP. RESULTS: The fluorescence intensity in the skin from melasma was higher for MC1R, αMSH at epidermis as at melanocytes (P < 0.05). There were no differences between the sites in epidermal protein expression of COX2, IL-1α, p53, WIF-1 and ASIP (P > 0.1). P53 was expressed only in epidermis, without difference between sites (P = 0.92). WNT1 was remarkable in the epidermis of melasma (P < 0.01), but not in dermis. Positive p38 cells were prominent in the upper dermis of melasma (P < 0.01), despite no marking in epidermis. CONCLUSION: Melanogenesis in melasma involves epithelial secretion of αMSH and activation of the Wnt pathway; nevertheless, it seems to be independent of the stimulation by ultraviolet radiation/p53, IL-1α, COX2/PgE2 , WIF-1 and ASIP. Damaged cells at upper dermis suggest the role of senescence/autophagy in sustained pigmentation in melasma.