Search

Acne is a common cause for post-inflammatory hyperpigmentation (PIH), particularly in patients with skin of color (SOC), and PIH is often more distressing to patients than the acne itself. Topical retinoids are approved for the treatment of acne and for pigmentation disorders such as melasma or mottled hyperpigmentation associated with photodamage; moreover, they have been shown to reduce hyperpigmentation in patients with SOC. Therefore, treatment with topical retinoids should be started as early as possible unless contraindicated. Use of novel formulations or application of commonly recommended moisturizers may help reduce irritation. Combining retinoids with other topical agents and procedures such as superficial chemical peels can help to improve hyperpigmentation. Primary acne lesions are likely to improve weeks before PIH resolves and helping patients manage their expectations may reduce frustration. Providing clinicians and researchers with more education about the presentation and management of dermatologic conditions in patients with SOC is also recommended.

Pseudomelanosis duodeni is a rare condition characterized by the endoscopic appearance of diffuse dark pigmentation of the duodenal mucosa. It is typically seen in older women and has been reported to be associated with hypertension, chronic renal disease, diabetes mellitus, gastrointestinal hemorrhage, and the use of medications such as oral iron, furosemide, thiazide, hydralazine, and propranolol. We present a case of pseudomelanosis duodeni appearing after 2 years of oral iron therapy in an 85-year-old woman. Although oral iron supplementation seemed the strongest possible etiology, our patient had multiple comorbidities and was on other medications that have been described as associations. The majority of individuals taking oral iron or under these clinical conditions do not develop this entity; some other factors in patients may be responsible for its occurrence.

Background: Vitiligo is a relatively common acquired pigmentation disorder that can cause significant psychological stress and stigmatism. Objective: This article aims to familiarize physicians with the clinical manifestations, evaluation, diagnosis, and management of vitiligo. Methods: A Pubmed search was conducted in Clinical Queries using the key term “vitiligo”. The search included meta-analyses, randomized controlled trials, clinical trials, observational studies, and reviews. The search was restricted to English language. The information retrieved from the above search was used in the compilation of the present article. Results: Approximately one quarter of patients with vitiligo have the onset before 10 years of age. Genetic, immunological, neurogenic and environmental factors may have a role to play in the pathogenesis. Vitiligo typically presents as acquired depigmented, well-demarcated macules/patches that appear milk- or chalk-white in color. Lesions tend to increase in number and enlarge centrifugally in size with time. Sites of predilection include the face, followed by the neck, lower limbs, trunk, and upper limbs. The clinical course is generally unpredictable. In children with fair skin, no active treatment is usually necessary other than the use of sunscreens and camouflage cosmetics. If treatment is preferred for cosmesis, topical corticosteroids, topical calcineurin inhibitors, and narrowband ultraviolet B phototherapy are the mainstays of treatment. Conclusion: The therapeutic effect of all the treatment modalities varies considerably from individual to individual. As such, treatment must be individualized. In general, the best treatment response is seen in younger patients, recent disease onset, darker skin types, and head and neck lesions. Topical corticosteroids and calcineurin inhibitors are the treatment choice for those with localized disease. Topical calcineurin inhibitors are generally preferred for lesions on genitalia, intertriginous areas, face, and neck. Narrowband ultraviolet B phototherapy should be considered in patients who have widespread vitiligo or those with localized vitiligo associated with a significant impact on the quality of life who do not respond to treatment with topical corticosteroids and calcineurin inhibitors.

Background Vitiligo is an acquired pigmentation disorder due to loss of melanocytes. Topical tacrolimus is effective in vitiligo treatment with minimal effect on extra-facial lesions. Objective To assess different methods of enhancing the absorption of topical tacrolimus in extra-facial vitiligo sites using microneedling and occlusion. Methods This study included 20 adult patients of both sexes with non-segmental vitiligo. Four extra-facial vitiligo lesions in each patient were randomly labeled A, B, C, and D and treated as follows: area A: tacrolimus ointment (0.03%) application twice/day, area B: microneedling once/week and tacrolimus ointment application directly after microneedling and twice/day the rest of the week, area C: microneedling once/week alone, and area D: tacrolimus ointment application twice/day under occlusion by polyethylene foil. The evaluation was done clinically by calculating the re-pigmentation percent after 6 months of treatment. Results Responders in area B were 45%, and 35% in area C, and 25% in both areas A and D. No statistically significant difference was detected regarding the re-pigmentation percent between the four areas (p > 0.05). No correlations were detected between re-pigmentation percent and patients' data. Conclusion Combination of microneedling and topical tacrolimus has an edge over monotherapy in vitiligo, and further studies are needed to verify such results.

Background Melanonychia refers to brown-black color pigmentation due to melanin or not-melanin deposition in the nail plate. Onychoscopy allows to distinguish if the pigmentation is due by melanin or not. The main causes of non-melanic pigmentation are subungual hematoma and pigmented onychomycosis. Fungal melanonychia (FM), is rare and may present as diffuse or longitudinal pigmentation. Differential diagnosis includes melanic activation, such as ethnic-type nail pigmentation or frictional melanonychia, but also versus melanic proliferation, such as nevus or nail melanoma. Fungal melanonychia can be due a colonization by fungi with black variant or by melanin activation due to inflammation of fungal invasion. Objectives The aim of paper is to increase clinical and dermoscopic knowledge of this increasingly frequent disease. Methods In this retrospective observational study, twenty patients with dermatophytic melanonychia were collected, with available clinical and dermoscopic pictures. The diagnosis of dermatophytic melanonychia was made based on clinical manifestation and mycological examination. KOH smear was performed in all cases. For each patient, clinical data included: age, gender, type of melanonychia and involved fingers. Results This study aimed to show increased incidence of dermatophytic melanonychia and its correct management. In addition, we reviewed our collected cases and described the clinical and dermoscopic features of dermatophytic melanonychia. Conclusions The results of this study showed that physicians should keep in mind the diagnosis of this increasing disease, and that it cannot be performed relying only on clinical grounds. We would like to highlight the importance of tools as KOH examination, culture, and dermoscopy.

Laugier-Hunziker syndrome being a rare pigmentation disorder chiefly involving lips and nails has so far been coincidentally diagnosed. In Nepal, Laugier-Hunziker syndrome has not been reviewed very well, and no case has been reported in the literature till date. To the best of our knowledge, the current report is the only one in the Nepalese scientific community but addressing the age of the patient it stands with a diagnostic quandary.

Background Picosecond lasers are increasingly being investigated in treating pigmentation disorders because they may provide better treatment efficacy and comfort compared with nanosecond lasers. Objective This study aims to evaluate the efficacy and side effect of a novel 670-nm picosecond laser in the removal of benign pigmented lesions (BPLs) in individuals with Fitzpatrick skin types (FST) III and IV. Materials and methods Fifteen subjects with solar lentigines and 7 subjects with ABNOMs received a single treatment with a 670-nm picosecond laser. Blinded physicians assessed the pigment clearance using a 5-category grading system scale. All subjects were evaluated at 1 month, 3 month, and 6 month after a single treatment. Adverse events were recorded at every follow-up visit. Results All subjects with lentigines had complete clearance (95%-100%) of lesions during 3-month follow-up after a single treatment session of 670-nm picosecond laser, whereas 75% of the subjects with ABNOMs noted fair lightning (25%-49%) of lesions. Mild hypopigmentation and hyperpigmentation were observed in 9% and 14% of the subjects, respectively, which resolved within 3 months after the treatment. Conclusion The novel 670-nm picosecond laser is a safe and effective treatment for BPLs in subjects with FST III and IV with low rates of transient adverse effects.

Pigmentation disorders are a frequent skin problem and incorporate a broad spectrum of diseases, caused by an abnormal melanin pigmentation or also non-melanin pigmentation of the skin. Both hypermelanosis and hypomelanosis can be hereditary or acquired. This article summarizes the treatment approaches that are used in the majority of acquired pigmentation disorders of the skin. The following forms of hypermelanosis are addressed: lentiginosis, hyperpigmentation due to endocrine disorders or other systemic diseases, drug-induced hyperpigmentation. Acquired hypomelanoses include postinflammatory hypomelanosis, chemical depigmentation, idiopathic guttate hypomelanosis and punctate leucoderma. With reference to non-melanin pigmentation, the exogenous pigmentation due to chemicals, metals and drug exposure are discussed. The treatment is primarily based on finding the cause of the alterations to the pigment. The affected area, age and ethnic origin are also important factors. The spectrum of therapeutic options is broad: topical agents, chemical peeling, systemic agents, laser and light-based treatment. As some of these treatment procedures can have side effects, the availability of a protocol that contains information on the drug concentration, dose, parameters for laser treatment and the number of sessions is important. For every disorder the specific dermatological treatment is presented even when some pigmentation alterations that occur in association with systemic diseases, are cured by the treatment of the primary disease. Most diseases are exacerbated by exposure to UV light. Therefore, sun protection is recommended and a cosmetic coverage is indicated.

Objective To determine the respective weights of certain facial signs on the assessment of perceived age and plumpness on Korean women of different ages. Material and methods Photographs were taken of the faces of 112 Korean women of different ages (18-80 years) under standardized conditions. These photographs allowed to focus and define 19 facial signs, which were then graded by 15 experts and dermatologists, using standardized scales provided by a reference Skin Aging Atlas. The facial signs were dispatched into 5 clusters, namely Wrinkles/Texture, Ptosis/Sagging, Pigmentation disorders, Vascular disorders, and Cheek skin pores. A naive panel, composed of 92 Korean women, of similar age range were asked, when viewing full-face photographs, to: (a) attribute on a 0-10 scale their perception of the skin plumpness (ie supple/hydrated/nourished) and (b) estimate the age of the subject. Results With the exception of Vascular disorders, the severity of all 4 clusters increased with age, although at different rates. The Wrinkles/Texture or Ptosis/Sagging showed a rather regular progression. Although perceived ages and real ages were found highly correlated, half of the subjects were judged older by 2-12 years. The facial signs/clusters were significantly correlated with perceived age, with the exceptions of vascular disorders, size of pigmentary spots and cheek skin pores. The weights in perceived ages of Wrinkles/Texture and Ptosis/Sagging represent 37% each and Pigmentation disorders at 26%. Skin plumpness was logically found significantly anti-correlated with perceived age. If, surprisingly, Vascular disorders were found not impacting the plumpness aspect, Cheek skin pores presented a clear influence. Conclusion Within facial clinical clusters, Wrinkles/Texture, Ptosis/Sagging, and Pigmentation disorders are major factors in the assessment of perceived age in Korean women. The perception of a decreased skin plumpness is significantly associated with increased perceived age.

Asthetisch storende Hyperpigmentierungen konnen postinflammatorisch auftreten oder sich infolge genetischer als auch hormoneller Einflusse, UV(Ultraviolett)-Exposition oder Medikamenteneinnahme entwickeln. Topische Therapien sollten uber wissenschaftlich hinreichend dokumentierte In-vivo- und In-vitro-Wirksamkeitsnachweise und uber in Studien belegte Wirkungen verfugen. Dieser Beitrag wird in wissenschaftlichen Studien belegte kosmetische und pharmazeutische topische Wirkstoffe gegen Hyperpigmentierung vorstellen. Eine Suche in der PubMed-Datenbank wurde im Oktober 2020 unter Verwendung verschiedener Wirkstoffnamen sowie den Suchbegriffen „Melasma“ und „Hyperpigmentierung“ durchgefuhrt. Zwei Gutachter pruften unabhangig voneinander die Titel, was zur Auswahl von 30 Arbeiten fuhrte. Hydrochinon, ein Tyrosinaseinhibitor, wird seit uber 40 Jahren zur Behandlung von Hyperpigmentierungen eingesetzt. Es ist der am haufigsten untersuchte Wirkstoff zur Aufhellung von Pigmenten. Trotz der begrenzten evidenzbasierten Forschung zu neuen Therapieansatzen zeigten mehrere Wirkstoffe eine Wirksamkeit als Depigmentierungsmittel, darunter Tyrosinaseinhibitoren, Substanzen, die den Zellumsatz erhohen, und Pflanzenderivate. Hydrochinon ist nach wie vor der Goldstandard fur die Behandlung von Hyperpigmentierungen, ebenso wie die 3er-Kligman-Formulierung aus Hydrochinon, Vitamin-A-Saure und Hydrokortison – in verschiedenen Modifikationen. Zusammengefasst benotigen Hyperpigmentierungen Kombinationstherapien aus Lokaltherapien unterschiedlicher Ansatze, begleitet von konsequentem UV-Schutz.

To determine the respective weights of certain facial signs on the assessment of perceived age, tired-look and healthy glow on Chinese men of different ages.Photographs were taken of the faces of 420 Chinese men of different ages, under standardized conditions. These photographs allowed to focus and define 15 facial signs, which were then graded by 15 experts and dermatologists, using standardized scales provided by a reference Skin Aging Atlas. The facial signs were dispatched into 5 clusters, namely wrinkles/texture, ptosis/sagging, pigmentation disorders, vascular disorders and cheek skin pores. A naïve panel, composed of 80 Chinese women, of similar age range were asked, when viewing full-face photographs, to: (i) attribute on a 0-10 scale their perception of both the tired-look and healthy glow aspects and (ii) estimate the age of the subject.With the exception of vascular disorders, the severity of all 4 clusters increased with age, although at different rates. The ptosis/sagging or pigmentation disorders showed a rather regular progression. Although perceived ages and real ages were found to be closely correlated, the vast majority of subjects were judged older by 2-10 years. The changes in facial signs (and their related clusters) were significantly correlated with perceived age, with the exceptions of skin spot density and cheek skin pores. Although the aspects of tired-look and healthy glow were logically found to be anti-correlated, tired-look was more statistically associated with perceived age for the five clusters. Signs of eye contour appear to be closely correlated with the perception of a tired-look.Within facial clinical clusters, wrinkles/texture and ptosis/sagging are major factors in the assessment of perceived age in Chinese men. Tired-look appears to be strongly associated with perceived age.De déterminer, pour des hommes chinois d’âges différents, les poids respectifs de certains signes faciaux entrant dans l’estimation de la perception des visages pour l’âge, l’air fatigué ou l’éclat. MATÉRIEL ET MÉTHODES: Les visages de 420 hommes chinois d’âges différents ont été photographiés dans des conditions standardisées. Ces clichés ont permis à 15 experts et dermatologistes d’évaluer 15 signes cliniques selon des échelles éditées dans les références Atlas Cliniques du Vieillissement. Ces signes faciaux sont regroupés dans 5 groupes (rides/texture, ptose/relâchement, désordres pigmentaires, désordres vasculaires, pores de la joue). Un panel de 80 consommatrices chinoises, d’un âge comparable, a été recruté pour donner leurs perceptions sur chaque visage complet photographié: d’abord en attribuant sur une échelle de 0 à 10 un score pour leurs perceptions de l’air fatigué et de l’aspect éclatant de santé, puis en estimant l’âge apparent du volontaire. RÉSULTATS: A l’exception des Désordres vasculaires, la sévérité des 4 groupes cliniques s’accroit avec l’âge selon des cinétiques différentes, parmi lesquelles la ptose/relâchement ou les désordres pigmentaires montrent la progression la plus constante et linéaire. Malgré une très importante et significative corrélation entre âge apparent et âge réel, une majorité des volontaires ont été jugés plus vieux que leurs âges réels, entre 2 et 10 ans. Les variations des signes faciaux (ou des groupes cliniques associés) ont été montrés significativement corrélées à l’âge apparent, à l’exception de la densité des taches pigmentaires et des pores de la joue. Bien que l’air fatigué et l’éclat sont logiquement observés comme anti-corrélés, c’est l’air fatigué qui se trouve le plus relié à l’âge apparent sur les 5 groupes cliniques. Les signes du contour des yeux apparaissent comme les plus corrélés à la perception de l’air fatigué.Parmi les groupes cliniques, les rides/texture et la ptose/relâchement sont les facteurs majeurs dans l’attribution d’un âge perçu pour les hommes chinois. L’air fatigué apparaît comme très fortement relié à l’âge apparent.

BACKGROUND Vitiligo is an acquired pigmentation disorder, which can have a negative effect on patient quality of life (QoL). AIM To evaluate QoL and psychiatric comorbidity in paediatric patients with vitiligo. METHODS In total, 30 patients aged 8-18 years who were diagnosed with vitiligo and 30 age- and sex-matched healthy controls (HCs) were included in the study. The Children's Depression Inventory, Screen for Child Anxiety Related Disorders, State-Trait Anxiety Inventory for Children and Child Somatization Inventory were completed for both patients and controls. The Schedule for Affective Disorders and Schizophrenia for School Age Children-Present and Lifetime Version (K-SADS-PL) was administered to all patients by a child psychiatrist. Families were also asked to complete the Pediatric Quality of Life Inventory and Emotion Regulation Checklist for children. RESULTS The K-SADS-PL evaluation showed that 90% of the patients in the vitiligo group had at least one psychiatric diagnosis, whereas this rate was 20% in the HCs (P

BACKGROUND Picosecond lasers appear to be effective and safe in treating pigmentation and photoaging disorders through laser-induced optical breakdown. OBJECTIVE To analyze the feasibility of photorejuvenation using picosecond lasers with diffractive lens array (DLA) in patients with melasma. METHODS Ten Asian (N = 10) women with melasma and Fitzpatrick skin Type IV were enrolled and treated using 755-nm picosecond alexandrite lasers with DLA. All individuals were assessed before treatment, and at 12, 20 weeks, and 1 year by post-hoc test on melasma area and severity index (MASI) and with VISIA Complexion Analysis System using percentile rank for measurement. RESULTS The median participant age was 46.5 years. The average MASI continually and significantly (p < .05) decreased until the 1-year follow-up, with the photoaging characteristics, such as wrinkles and red areas improving simultaneously (p < .05). Spots, texture, pores, ultraviolet (UV) spots, brown spots, and porphyrins exhibited alleviation, but this improvement relapsed by the 1-year follow-up. No postinflammatory hyperpigmentation or hypopigmentation occurred. CONCLUSION In patients with melasma, picosecond laser treatment with DLA may alleviate pigmentation disorder and the related photoaging characteristics (e.g., wrinkled skin and increased vascularity), and the effects may be maintained for a long time. Nevertheless, post-treatment clinical visits every 3 to 6 months are recommended.

Coat colour in livestock speciesis one of the most distinctive traits that characterise many different breeds. Pigmentation does not affect only skin and hairs but also the eyes. Few genomic studies in cattle and horses also investigated iris pigmentation, but no similar studies was conducted in pigs thus far. In this study we analysed eye colour diversity in a Large White pig population (n=897) and reported the results of genome-wide association studies based on several comparisonsincluding pigs having four main eye colour categories(three with both pigmented eyes of different brown grades: pale, 17.9%; medium, 14.8%; and dark, 54.3%; another one with both eyes completely depigmented, 3.8%) and heterochromia patterns (heterochromia iridis, i.e. depigmented iris sectors in pigmented irises, 3.2%; heterochromia iridium, i.e. a whole eye iris of depigmented phenotype and the other eye with the iris completely pigmented, 5.9%). Pigs were genotyped with the Illumina PorcineSNP60 BeadChip and GEMMA was used for the association analyses. The results indicated that the eye pigmented patterns (different grades of brown pigmentation), the total absence of pigmentation in the both eyes, and heterochromia iridis defect were under controlled of SLC45A2 (on chromosome 16, SSC16), EDNRB (SSC11) and KITLG (SSC5), respectively. In addition, to new candidate associations for the eye depigmented patterns were also identified for SNPs on two SSC4 regions (including two candidate genes: NOTCH2 and PREX2) and on SSC6, SSC8 and SSC14 (including COL17A1 as candidate gene). This study provided useful information to understand the genetic mechanisms affecting eye pigmentation in pigs.

The chemical warfare agent sulfur mustard (SM) affects all cells in the epidermis including melanocytes which are responsible for melanin synthesis. After exposure to SM, pigment abnormalities like hypo- and hyperpigmentation can occur. The underlying molecular pathomechanisms of SM exposure on human melanogenesis have not been elucidated so far. In our study, we investigated the effect of SM on human melanocytes and melanogenesis. Normal human epidermal melanocytes (NHEM) were used as in vitro model and they were exposed to different concentrations of SM (4.5 μM-100 μM). Melanin production was analyzed by absorption measurements at 405 nm. In addition, quantitative real-time PCR (qPCR) and Western blot experiments were performed to determine the expression of essential melanogenesis-related proteins including tyrosinase (TYR), tyrosinase-related protein (TRP) 1 and 2 and microphthalmia transcription factor (MITF). Our findings demonstrated that exposure to low SM concentrations increased melanin synthesis accompanied with an increase in protein expression. In contrast, high SM concentrations led to decreased melanin content and a downregulation in expression of all investigated melanogenesis-associated proteins. We concluded that low SM concentrations may cause hyperpigmentation while high SM concentrations decreased melanin content which may explain hypopigmented skin areas in SM exposed patients.

As a main part of pigmentation disorders, skin depigmentation diseases such as vitiligo and achromic naevus are very common and get more attention now. The pathogenesis of depigmentation includes melanocyte dysfunction and loss, which are possibly caused by heredity, autoimmunity and oxidative stress. Among them, oxidative stress plays a key role; however, few clinical treatments can deal with oxidative stress. As reported, Cistanche deserticola polysaccharide (CDP) is an effective antioxidant; based on that, we evaluated its role in melanocyte and further revealed the mechanisms. In this study, we found that CDP could promote melanogenesis in human epidermal melanocytes (HEMs) and mouse melanoma B16F10 cells, it also induced pigmentation in zebrafish. Furthermore, CDP could activate mitogen‐activated protein kinase (MAPK) signal pathway, then up‐regulated the expression of microphthalmia‐associated transcription factor (MITF) and downstream genes TYR, TRP1, TRP2 and RAB27A. Otherwise, we found that CDP could attenuate H2O2‐induced cytotoxicity and apoptosis in melanocytes. Further evidence revealed that CDP could enhance NRF2/HO‐1 antioxidant pathway and scavenge intracellular ROS. In summary, CDP can promote melanogenesis and prevent melanocytes from oxidative stress injury, suggesting that CDP helps maintain the normal status of melanocytes. Thus, CDP may be a novel drug for the treatment of depigmentation diseases., Cistanche deserticola polysaccharide (CDP) promotes melanogenesis in human epidermal melanocytes via activating mitogen‐activated protein kinase (MAPK) signal pathway, then up‐regulates the expression of MITF, TYR, TRP1, TRP2, and RAB27A. Otherwise, CDP can attenuate H2O2‐induced oxidative stress in melanocytes via enhancing NRF2/HO‐1 antioxidant pathway and scavenge intracellular ROS.

Background Vitiligo is a relatively common pigmentation disorder in which the skin melanocytes are lost or destroyed. Experimental downregulation of long noncoding RNA H19 (lnc RNA H19) in keratinocytes promoted melanocytes melanogenesis. lnc RNA H19 acts as an important regulator for micro-RNA let7a (miRNA let7a). miRNA let7a has a powerful role in regulation of cell survival and inducing cell apoptosis. Objectives This study was performed to clarify the suggested role of lnc RNA H19 and miRNA let7a derived from human skin exosomes in vitiligo pathogenesis. Patients and methods The study included 50 patients with vitiligo vulgaris and 50 healthy volunteers serving as controls. From all patients, 4-mm punch skin biopsies were taken. Skin biopsies were examined for lnc RNA H19 and miRNA let7a genes expression using RT-PCR technique. Results The expression of lnc RNA H19 and miRNA let7a in vitiligo lesions (1.736±0.84 and 6.7±2.26 pg/mg, respectively) was significantly higher than their expression in controls (0.8462±0.3483 and 1.514± 0.9202 pg/mg, respectively) (P

Albinism has been sporadically recorded in Virginia opossums (Didelphis virginiana) in the United States and Mexico, but records of pigmentation disorders in other Didelphis spp. are rare. The Brazilian common opossum (Didelphis aurita) is a cat-sized nocturnal omnivorous marsupial that inhabits Atlantic and Araucaria forests in South America. A litter of five young Brazilian common opossums was rescued at Espírito Santo state, southeast Brazil, of which two were albinos (one male, one female) and the remaining had normal pigmentation (three males). The two albinos had a complete lack of integumentary and retinal pigmentation, representing the first recorded cases of albinism in this species (and the first record in a Didelphis sp. other than the Virginia opossum).

Murine models recently provided important information on the pathogenesis of pigmentation disorders. Multiple factors influence melanocyte function at various levels, such as melanoblast development and migration from the neural crest to peripheral sites, melanoblast differentiation into melanocytes, melanocyte survival and, finally, synthesis of melanosomes and melanins. Mutations affecting any of these steps result in hereditary hypomelanoses. In some of these diseases, melanocytes are absent, either because of a defect in migration of melanoblasts from the neural crest, their inability to survive and/or proliferate in colonized territories (piebaldism and Waardenburg syndromes), or because of programmed melanocyte destruction (e.g. vitiligo). In other entities, the melanocytes are present but functionally deficient (oculocutaneous albinisms and pigmentary dilutions). This comprehensive review will introduce the genetic regulation of melanocytogenesis and melanogenesis and the correlations between genetic abnormalities and hypopigmentation clinical disorders.

Background Melasma is a complex and multipathophysiological condition that is challenging to treat. The roles of each element in the dermis were highlighted in this recent year due to targeting it with emerging therapies. Although some studies have demonstrated abnormal findings in the dermis of melasma lesions, there are no integrated data regarding these findings. Purpose This article aims to discuss each finding in the dermis of melasma lesions and to provide some ideas about treatment options. Methods An Internet search was completed using the MEDLINE, Embase, Scopus, and Google Scholar databases for relevant literature through June 2021 and reference lists of respective articles. Only the articles published in English language were included. Results Several studies have focused on the dermal changes in melasma. Common findings included basement membrane disruption, pendulous melanocytes, marked solar elastosis, increased melanophages, increased mast cells, and neovascularization. In addition, each of them had the specified mechanism that may relate with the others. Conclusion Several changes in the dermis of melasma lesion may be connected with pathological changes in the epidermis. This may serve as a potential target treatment for melasma, which requires a multimodal approach.

Microneedling can accelerate skin repair through numerous complex processes triggered by micro-injuries it produces on the skin surface with very thin needles. The current growth in the application of microneedling in the treatment of cutaneous diseases can be explained by its numerous effects on the skin as reported in the literature. Despite the numerous studies conducted on the application of microneedling in the treatment of skin lesions, its effects on pigmented skin lesions have remained relatively unexplored. The present review comprises an examination of the evidence for the application of microneedling in skin diseases in general and a comprehensive review of the applications of microneedling in pigmentation disorders. The review involved a search of all clinical studies, including trials, case reports, and case series, in the databases MEDLINE/PubMed and Google Scholar using the following keywords: "microneedling", "dermal needling", "percutaneous collagen induction", "skin needling", "dermaroller", and "dermatology disorder". Pertinent data were extracted from all relevant articles published from 1990 to April 2021, and focused on the application of microneedling in the treatment of pigmented skin lesions. Despite the limited number of available studies, evidence suggests the effectiveness and safety of microneedling in treating vitiligo, melasma, and periorbitalhypermelanosis. It is noteworthy that the combination of any type of non-aggressive needing technique with other effective therapies (especially topical agents and mesotherapy) yields more promising therapeutic results than single therapy for melasma, dark cycles and vitiligo as the prototype of pigmentary disorders. However, single needling therapy is significantly effective, too. This article is protected by copyright. All rights reserved.

Background: Nevus of Ota is a psychologically burdensome facial pigmentation disorder common in Asian populations. While laser therapy is currently first-line treatment, guidelines for when to initiate treatment are not yet established. We determined an optimal age-stratified timeline for initiating laser therapy in treating nevus of Ota and maximizing treatment efficacy, safety, and reducing risk of recurrence. Methods: A 10-year retrospective chart review of 84 patients presenting to a tertiary care clinic with nevus of Ota who underwent laser treatment between January 2008 to January 2018 was done. Initiation of treatment ranged from ages 4-months to 50-years. Efficacies among age of treatment onset were compared using a multivariate ordered logistic random effects model. Contingency table analysis, binary logistic regression model and receiver operating characteristic analyses were used to assess recurrence rate and compare complications among different age groups. Findings: Analysis identified early initiation of laser therapy before the age of 5 as a significant factor in reducing the number of treatments necessary to achieve aesthetic improvement (P 25, 50, and 75% clearance of pigmentary lesions, respectively. The 66 patients (78.6%) initiating treatment after 5 years old required an average of 3, 7 and 11 sessions to achieve comparable clearance. Additionally, the risk of post-inflammatory hyperpigmentation was significantly lower in patients starting treatment before 5 years of age (P 95% clearance. Interpretation: Initiation of laser treatment for nevus of Ota before age 5 significantly improves therapeutic outcomes and reduces the incidence of adverse effects, and recurrence. Furthermore, early treatment initiation and improved outcomes may also yield potential psychological benefits to the patients. Trial Registration: ClinicalTrail.gov PRS. number: NCT04481178. Funding Statement: None. Declaration of Interests: None. Ethics Approval Statement: Approved by Siriraj Institution Review Board (Si 347/2020).

In veterinary dermatology, disorders of pigmentation are disorders of melanogenic pigmentation; the role of other factors that contribute to pigmentation in hairless skin, such as haemoglobin or carotenes, is anecdotal. Melanin pigments are synthesized in specialized cells, the melanocytes, which are present in the hair follicle and epidermal basal layer. Melanocytes are dendritic cells that send connections to a determined number of neighbouring keratinocytes, to form a pigmentary functional unit. In the epidermis every melanocyte is associated with 36 keratinocytes, whilst the bulbar melanocyte is associated with only four cortical keratinocytes. These follicular melanocytes have specific properties. They are taller than epidermal melanocytes and synthesize larger melanosomes, which are distributed individually to the cortical cells. They are characterized by cyclic activity, synthesizing melanin during the anagen phase and entering apoptosis during the catagen phase, to be replaced at the next cycle by non-differentiated cells that reside in the permanent upper part of the outer root sheath. This chapter considers the following: Hypopigmentation disorders; and Hyperpigmentation disorders.