Melanogenesis is a melanin-forming process responsible for protecting the skin against ultraviolet radiation damage. An excess production of melanin, however, may result in hyperpigmentation (darkening of the skin) to adverse dermatological effects (freckles, solar lentigines, and melasma) and skin cancer. These hyperpigmentary skin disorders may also have a major effect on a person's appearance and could even result in emotional and mental distress, as well as a diminished quality of life. A large number of melanogenesis inhibitors have been discovered, but most of them appeared to have undesirable side effects. Therefore, in order to better understand the mechanisms of hyperpigmentary skin disorders and to establish effective and safe melanogenesis inhibitors, more fundamental research is needed. Apart from tyrosinase blockers, there are also alternative approaches that involve the manipulation of melanogenesis regulatory pathway such as α-melanocyte-stimulating hormone blockers, melanosome transferase inhibitors, and cytokines. This review abridges data on the different melanogenesis inhibitors and depigmentation agents from both natural and synthetic agents from the last few years.

Background: Vitiligo is an acquired, idiopathic skin disorder that can significantly affect the health-related quality of life (QoL). The vitiligo-specific QoL instrument (VitiQoL), recently developed by an American group, was found to be a reliable patient-reported outcome measure in both Brazilian and Iranian patients. Methods: The VitiQoL was initially cross-culturally adapted to Chinese through forward-backward translation. The Chinese version of the VitiQoL was then distributed to 182 vitiligo patients together with the dermatology life quality index (DLQI) and Skindex-16 questionnaire. Then, the reliability and validity of the Chinese version of the VitiQoL was assessed by statistical analysis. Results: The Chinese version of the VitiQoL showed high internal consistency (Cronbach alpha = 0.958) and test–retest reliability (intraclass correlation coefficient = 0.887). Convergent validity testing showed that the correlation coefficient for the Chinese VitiQoL and DLQI was 0.70 (P < 0.01), the Chinese VitiQoL and Skindex-16 each was 0.84 (P < 0.01), and for the Chinese VitiQoL (questions 1–15 and 16) was 0.62 (P < 0.01). Confirmatory factor analysis revealed two important factors within the VitiQoL: Participation limitation and stigma. Conclusion: The Chinese version of the VitiQoL questionnaire has sufficient reliability and validity to be used to evaluate Chinese vitiligo patients' QoL.

Background: Previous studies showed a higher risk of renal disease among patients with psoriasis; however, this association has been inconsistent. Objectives: This study aimed to carry out a comparison in the probability from suffering renal diseases—including chronic kidney disease (CKD), end-stage renal disease (ESRD), IgA nephropathy (IgAN), glomerular disease (GD), and those resulting in death caused by other renal diseases—in patients with psoriasis. Methods: The systematic review and meta-analysis was conducted to identify cohort studies with reported hazard ratios (HRs) and a 95% confidence intervals (CIs) for the renal outcomes among patients with psoriasis. The meta-analysis was analyzed with the random-effects modeling and was further stratified by psoriasis severity. Results: Three studies were included. Compared to controls without psoriasis, patients with psoriasis had increased risks of CKD (HR: 1.53; 95% CI: 1.20–1.96) and ESRD (HR: 1.24, 95% CI: 1.06–1.46). The risks of CKD (HR: 1.91, 95% CI: 1.78–2.05) and ESRD (HR: 2.72, 95% CI: 1.71–4.34) were increased in servere psoriasis patients. Due to substantial heterogeneity across enrolled studies (I² = 95%), the risk of CKD in mild psoriasis was insignificant (HR: 1.14, 95% CI 0.87–1.48). Two studies identified severe psoriasis were related to higher risks of IgAN and GD, whereas one study found that mild psoriasis was associated with an increased risk of death from renal disease. Conclusion: Patients with severe psoriasis have a higher risk of incident CKD, ESRD, and GD. However, we only identified two cohort studies that compared the risk of IgAN and GD in psoriasis patients to general populations. It is difficult to conclude that severe psoriasis was associated with higher risks of IgAN and GD. For mild psoriasis, the association with renal disease was less consistent.

Background: Dactylitis is a characteristic feature of psoriatic arthritis (PsA). However, early diagnosis of mild dactylitis is challenging and image examination, such as ultrasonography (US), can be helpful. Objectives: We aimed to compare the clinical diagnosis of dactylitis made by the dermatologist and ultrasonographic diagnosis by the rheumatologist. Methods: Consecutive patients diagnosed with peripheral PsA seen in the dermatologic clinics were referred to the same dermatologist for evaluation of dactylitis. Consecutive patients with and without clinical dactylitis were diagnosed in 19 and 19 patients, respectively, by the referred dermatologist. All patients were then referred to an experienced rheumatologist unaware of the clinical diagnosis for sonographic examination of all 20 digits. Dactylitis under US was diagnosed when both proximal and distal parts of a digit were at least 0.25 mm larger than the contralateral digit. Results: For the clinical dactylitis group, 7 (36.8%) patients had more dactylitis diagnosed by US than clinically, and 2 (10.5%) patients had no dactylitis diagnosed by US. For the clinically no dactylitis group, 4 (21.1%) patients had no diagnosis of dactylitis by US, and most of these patients (78.9%) were diagnosed with dactylitis under US by the rheumatologist. More digits affected by dactylitis were found for both groups, although no statistically significant differences were found, probably due to the small sample size. Conclusion: The results revealed concordance between the dermatologist and rheumatologist for clinical dactylitis but not for patients without dactylitis. For PsA patients, US is more sensitive and useful for early dactylitis diagnosis in a dermatologic clinic.

Background: The roots of Salvia miltiorrhiza Bunge (Lamiaceae) have been often used to treat vitiligo in clinical for many years. However, the main ingredient basis of efficacy has not been known. Objectives: We investigated whether the two main constituents of S. miltiorrhiza, major hydrophobic compound tanshinone IIA (Tan IIA) and the major hydrophilic compound salvianolic acid B (Sal B), had the same melanogenic activity. Methods: To testify the potential roles of Tan IIA and Sal B in pigmentation, tyrosinase (Tyr) activity, melanin synthesis ability, and the molecular mechanisms stimulating melanin production were determined in B16F10 melanoma cells. Results: Tan IIA promoted melanogenesis and enhanced Tyr activity at its maximum concentration (10 μM), whereas that of Sal B had no effect. Furthermore, the color of cell pellets and morphological observation of B16F10 cells were visibly darkened. Regarding molecular mechanisms, Western blot results showed that Tan IIA (1, 3, and 10 μM) dose dependently increased the level of phosphorylation of p38 mitogen-activated protein kinase (MAPK) and c-Jun N-terminal kinase MAPK, respectively. However, it decreased phosphorylation in extracellular signal-regulated protein kinase 1/2 MAPK signaling. Meanwhile, Tan IIA promoted the expression of microphthalmia-associated transcription factor and Tyr. Conclusion: Tan IIA might be a melanogenic ingredient basis of S. miltiorrhiza to increase the Tyr activity by activating the upstream MAPK signaling pathways, thereby contributing to pigmentary processing.

Endometriosis has been associated with the risk of several autoimmune diseases; however, its relationship with alopecia areata (AA) remains unknown. This study aimed to investigate the risk of AA in patients with endometriosis. Participants were recruited from the National Health Insurance Research Database in Taiwan. We identified female patients with endometriosis between January 1, 1998 and December 31, 2011. For each patient with endometriosis, four control subjects were included in the control group matched for age, sex, monthly premium, and residence. Patients and control subjects were followed up until AA diagnosis, death, or December 31, 2013, whichever occurred first. The Cox regression model was used for the analyses. Overall, we included 35,123 patients with endometriosis and 140,492 control subjects. Compared with control subjects, patients with endometriosis had an adjusted hazard ratio of 5.60 (95% confidence interval 4.03–7.79) for AA after controlling for age, socioeconomic status, and comorbidities. In conclusion, patients with endometriosis had a significantly increased risk of AA. Further studies are necessary to investigate the pathophysiology underlying the relationship between endometriosis and AA.