Perinatal Outcome of Pemphigoid Gestationis: A Report of Three Cases and Review of the Literature.

Pemphigoid gestationis (PG) is a rare autoimmune blistering disorder that typically manifests during the second or third trimester of pregnancy. It is characterized by intensely pruritic urticarial plaques and blister formation, driven by an autoimmune response against the BP180 protein in the basement membrane. In this report, three cases of PG are presented, each illustrating distinct clinical courses and management strategies. The first case involves a 32-year-old primigravida at 31 weeks of gestation who presented with abdominal blisters that were unresponsive to topical steroids. Oral prednisone at a dosage of 15 mg was initiated at 33 weeks, leading to the resolution of the rash by 37 weeks. She subsequently delivered vaginally at 40 weeks. The second case concerns a 37-year-old multigravida who developed blisters on her limbs and abdomen at 27 weeks, which improved with the application of topical steroids. Due to a history of a previous cesarean section, she delivered via elective cesarean section at 38 weeks. The third case involves a 35-year-old multigravida who experienced fetal growth restriction starting from 29 weeks. She developed a mild erythematous, pruritic rash, and blisters at 33 weeks and required an emergency cesarean section at 33 weeks due to non-reassuring fetal status. The diagnosis of PG was confirmed postpartum. These cases underscore the clinical variability and potential complications associated with PG. They also suggest that the severity of PG's cutaneous manifestations may not directly correlate with pregnancy outcomes. Early detection and individualized management are crucial to optimizing both maternal and neonatal outcomes.

When the Blisters Reach the Heart: An Uncommon Case of Cardiac Involvement in Bullous Pemphigoid.

Bullous pemphigoid is an autoimmune blistering disorder predominantly affecting the elderly, with rare systemic complications, including cardiac involvement. This case study presents a 46-year-old female with a history of arterial hypertension who developed complete heart block (CHB) associated with bullous pemphigoid. The patient initially presented with bilateral lower limb swelling and discoloration, later diagnosed as bullous pemphigoid following the appearance of characteristic skin lesions. Concurrently, she was found to have asymptomatic bradycardia, with an electrocardiogram confirming CHB. After ruling out other causes of heart block, a dual-chamber pacemaker was implanted, and the patient was treated with immunosuppressive therapy to control the autoimmune blistering disorder. This case highlights the rare but significant association between bullous pemphigoid and CHB, emphasizing the importance of multidisciplinary care and timely intervention in managing such complex cases.

Case report: A novel high-dose intravenous immunoglobulin preparation for the treatment of severe pemphigus vulgaris failing standard therapy.

Pemphigus vulgaris (PV) is a severe autoimmune bullous dermatosis that is characterized by autoantibodies against epidermal adhesion proteins causing painful mucosal and skin blistering. Standard treatments for PV include corticosteroids, steroid-sparing immunosuppressants, or intravenous monoclonal anti-CD20-antibody therapy. The European guidelines suggest high-dose intravenous immunoglobulin (IVIg) therapy as a promising approach for severe or treatment-resistant cases. We report on a 65-year-old woman with severe and recurrent disease who achieved long-term disease stabilization with IVIg treatment. Because of recurrent fatigue and headache, the patient was switched to an alternative IVIg preparation with a novel manufacturing process, thus ensuring high purity and better tolerability. We observed excellent efficacy, yet side effects remained largely unchanged. Further studies are necessary to evaluate the long-term efficacy and tolerability of this new IVIg preparation.

A Clinico-Histopathological Study of Nail Dermatoses in a Tertiary Care Hospital.

Introduction Nail disorders account for an important component of all dermatological conditions. Nail abnormalities can result from local pathology or systemic diseases. Pathologies can lead to pain and impaired fine touch and are aesthetically distressing. Clinical assessment of nail pathologies is seldom accurate; moreover, the limited available investigative modalities make it difficult to correctly diagnose the disorders. Nail biopsies provide crucial histological information, especially for nail-limited dermatoses, though they are infrequently used and technically challenging. Proper biopsy techniques are vital to avoid complications like nail dystrophy and to ensure accurate diagnoses and effective treatments. Materials and methods A cross-sectional and observational study was conducted in the Dermatology Department of a tertiary care hospital in Maharashtra from November 2022 to July 2024, involving 51 patients aged 8-80 years with undiagnosed nail dermatoses. Patients with bleeding disorders, anesthesia allergies, and peripheral vascular diseases were excluded. Ethical clearance and written consent were obtained. In the case of pediatrics, patients' parental consent was obtained. Observation and results The age of the patients ranged from eight to 74 years, with a mean age of 38.04 years. The most affected age groups were 20-29 and 30-39 years old. Nineteen (37%) were manual laborers, followed by 10 (20%) students and nine (18%) professional workers. Symptoms lasted from one month to eight years, with a mean duration of 16.65 months. The most common dermatoses diagnosed clinically were as follows: 18 (35.3%) were onychomycosis, 16 (31.4%) were psoriasis, and eight (15.7%) were lichen planus. However, on histopathology, 20 (37.2%) were onychomycosis, followed by 16 (31.4%) of psoriasis, and eight (15.7%) were lichen planus. Conclusion This study highlights the critical role of nail biopsies in diagnosing nail disorders, particularly among middle-aged males who were manual laborers by occupation. It underscores the importance of combining clinical and histopathological approaches to accurately diagnose and manage, advocating for continued research and collaboration to improve patient outcomes.

A Preliminary Study Using High-Frequency Ultrasound to Evaluate Vulvar Skin With Lichenoid Vulvar Dermatoses.

BACKGROUND: Lichenoid vulvar dermatoses (LVD) are inflammatory diseases primarily affecting the vulva and anus. This study aims to evaluate the skin changes in patients with LVD using high-frequency ultrasound. METHODS: Forty-five patients with LVD, who attended Henan Provincial People's Hospital from November 2021 to March 2024, were selected. According to the pathological conclusions, patients were divided into two groups: the vulvar lichen sclerosus (VLS) group (n = 24) and the vulvar lichen simplex chronicus (VLSC) group (n = 21). Thirty age- and BMI-matched healthy women were selected as the control group. We assessed the epidermal thickness, subepidermal low echogenic band (SLEB) thickness, dermal thickness, and vascular index (VI) among the three groups. Receiver operating characteristic curve (ROC) analysis was performed to determine the diagnostic efficacy of these ultrasound parameters for LVD. Binary logistic regression was used to investigate risk factors influencing LVD pathology in VLS patients. RESULTS: Epidermal thickness, SLEB thickness, dermal thickness, and VI were increased in the VLS and VLSC groups compared to the control group (p < 0.05). There were no statistically significant differences in ultrasound parameters between the VLS and VLSC groups (p > 0.05). The ROC curves showed that the area under the curve (AUC) value for the dermis (AUC = 0.882) was the largest for VLS, and VI (AUC = 0.917), it was the largest for VLSC. Binary logistic regression indicated that having an allergic disease was a risk factor for VLS between VLS and VLSC groups (OR = 6.797, p = 0.028). CONCLUSION: High-frequency ultrasound can detect thickening of the skin and increasing VI in patients with LVD, which can be helpful in the evaluation and management of LVD.

Clinical and Dermoscopic Patterns of Basal Cell Carcinoma and Its Mimickers in Skin of Color: A Practical Summary.

The diagnosis of basal cell carcinoma (BCC) in dark phototypes can be a challenging task due to the lack of relevant clues and its variable presentation. In this regard, there is growing evidence that dermoscopy may benefit the recognition of BCC even for skin of color (SoC). The objective of this review is to provide an up-to-date overview on clinical and dermoscopic patterns of BCC in SoC, also comparing such findings with those of the main clinical mimickers reported in the literature. A comprehensive search of the literature through the PubMed electronic database was carried out in order to identify papers describing the clinical and dermoscopic features of BCC in dark phototypes (IV-VI). By finding macroscopic clinical presentations of BCCs in SoC patients and any possible clinical mimickers considered in the retrieved papers, we built a differential diagnosis list and analyzed the dermoscopic findings of such conditions to facilitate the diagnosis of BCC. BCC in darker skin may present as pigmented nodular lesions, pigmented patches or plaques, ulcers, erythematous nodular lesions, erythematous plaques or patches, or scar-like lesions, depending on its subtype and body site. The differential diagnosis for BCC in patients with SoC includes squamous cell carcinoma, melanoma, nevi, adnexal tumors and sebaceous keratosis. Additionally, it differs from that of Caucasians, as it also includes lesions less common in fair skin, such as dermatosis papulosa nigra, melanotrichoblastoma, and pigmented dermatofibrosarcoma protuberans, and excludes conditions like actinic keratosis and keratoacanthoma, which rarely appear in darker skin. The resulting differences also include infectious diseases such as deep cutaneous mycosis and inflammatory dermatoses. The most prevalent differentiating dermoscopic feature for BCC includes blue, black and gray dots, though arborizing vessels still remain the predominant BCC feature, even in dark phototypes. Diagnostic approach to BCC in dark-skinned patients varies due to the prevalence of dermoscopy findings associated with hyperpigmented structures. Clinicians should be aware of such points of differentiation for a proper management of this tumor in SoC.

An Unusual Case of Kyrle Disease.

Kyrle disease is one of the acquired perforating disorders (APDs), commonly associated with type 2 diabetes, chronic kidney disease, and other pruritic conditions. Here, we report a case of Kyrle disease with characteristic transepidermal elimination of dermal contents on histopathology. However, the only abnormal laboratory finding in our patient was hyperuricemia, and none of the commonly associated underlying conditions were found. The precise etiopathogenesis of APD is poorly understood. Abnormal glycation of collagen in diabetes and defective follicular keratinization following chronic friction have been commonly implicated in the pathogenesis. Treatment of the underlying cause is the mainstay; however, our patient responded well to acitretin, dapsone, and topical corticosteroids. Further studies need to be done to evaluate other possible causes, such as hyperuricemia in our patient, especially when none of the classical associations are present after a detailed workup.

Bimekizumab for the treatment of hidradenitis suppurativa.

Hidradenitis suppurativa (HS) is a painful, inflammatory dermatosis involving recurrent abscesses, nodules and tunnels in intertriginous regions. Biologics and other immunomodulators have significantly expanded the treatment options available for HS. Bimekizumab is a monoclonal antibody targeting both interleukin-17A and interleukin-17F, key mediators of inflammation, that is already approved for psoriasis, psoriatic arthritis and axial spondylarthritis. It is currently pending FDA review for HS treatment but has already received marketing authorization for this indication in Europe. This review aims to explore drug-specific characteristics of bimekizumab including its mechanism of action, pharmacokinetics and pharmacodynamics and the current state of the literature regarding its use in HS such as safety, efficacy and dosing, while highlighting its implications in clinical practice. Recent Phase II and III trial data demonstrating positive efficacy and safety profiles in the treatment of HS will also be detailed.

What is this review about? Hidradenitis suppurativa (HS) is a skin condition that commonly causes painful abscesses, nodules, tunnels and scars with a predilection for areas of skinfolds like the underarms, under the breast and genital area. Multiple treatment options exist but none completely cure the disease. Treatments that target specific signals involved in the human immune system response are currently being used and developed for HS. Bimekizumab is an antibody-based treatment being considered for HS. It targets interleukin-17A and interleukin-17F (IL-17A/F), which are both involved in the inflammation in HS and other inflammatory conditions like psoriasis. In this review, we discuss how it works, its safety and its usefulness for the treatment of HS.What were the results? The available data show that bimekizumab is effective at treating the symptoms of moderate to severe HS by reducing the number of skin lesions and preventing new ones from developing in more patients compared with no medications. Additionally, it reduces pain from HS and improves patient quality of life at a higher level than a placebo medication. Bimekizumab was also found to be safe with few serious side effects. Common non-serious side effects included infections, gastrointestinal symptoms and headaches.What do the results mean for managing hidradenitis suppurativa? Bimekizumab is a viable treatment option for HS and may be considered in patients with moderate to severe HS if they have failed other treatment options. However, further research and long-term safety research is needed to support these recommendations.

Subcutaneous Sweet's Syndrome Presenting With a Single Cutaneous Lesion on the Thigh.

Sweet's syndrome (SS), also known as acute febrile neutrophilic dermatosis, manifests as tender, erythematous skin lesions such as papules, nodules, and plaques that may appear vesicular or pustular. The condition is characterized by widespread infiltrates mainly consisting of mature neutrophils, usually in the upper dermis. Erythema nodosum (EN) is a form of septal panniculitis marked by tender, erythematous lesions primarily appearing on the lower legs. Additionally, subcutaneous Sweet's syndrome (SSS) is a rare variant of SS that mainly involves the subcutaneous adipose tissue. Skin lesions in SSS generally present as tender, erythematous subepidermal nodules on the extremities, morphologically resembling EN. Both EN and SS can present with fever, malaise, gastrointestinal disturbances, lymphadenopathy, arthralgia, increased white blood cell (WBC) count with neutrophilia, elevated C-reactive protein (CRP), and elevated erythrocyte sedimentation rate (ESR), making differentiation between them often challenging. Therefore, histopathologic evaluation is necessary for an accurate diagnosis. In our case, the patient exhibited a very painful plaque measuring 20 cm in diameter on the upper thigh without significant neutrophil infiltration in the dermis, but with subcutaneous septal neutrophil infiltration. Generally, SS shows stronger leukocytosis with neutrophilia than EN does. Considering the clinical symptoms, laboratory results, and clinical progression, the clinicopathological findings aligned more closely with SSS than EN. This article describes a rare case of SSS presenting with a single cutaneous lesion on the thigh, which mimicked the histopathological features of EN.

The alleviative effects of canagliflozin on imiquimod-induced mouse model of psoriasis-like inflammation.

Psoriasis is a life-long immune-mediated dermatosis with thickened, reddish, and flaky skin patches. Canagliflozin is a gliflozin antidiabetic with non-classical remarkable antioxidative, anti-inflammatory, anti-proliferative, and immune-modulating effects. The aim of this study is to examine the probable effects of topical canagliflozin on a mouse model of imiquimod-provoked psoriasis-like dermatitis. The study evaluated 20 Swiss white mice, sorted haphazardly into 4 groups of 5 animals each. Every mouse, with the exception of the control group, had imiquimod applied topically to their shaved backs for 7 days. The control group included healthy mice that were not given any treatment. Mice in the other three groups underwent topical treatment with vehicle (induction group), 0.05% clobetasol propionate ointment (clobetasol group), or 4% canagliflozin emulgel (canagliflozin 4% group) on exactly the same day as imiquimod cream was administered. Topical canagliflozin markedly lowered the intensity of imiquimod-provoked psoriasis eruptions, featuring redness, glossy-white scales, and acanthosis, while also correcting histopathological aberrations. Canagliflozin administration to imiquimod-exposed animals resulted in significantly decreased cutaneous concentrations of inflammatory mediators such as IL-8, IL-17, IL-23, and TNF-α, with raised levels of IL-10. Canagliflozin further lowered proliferative factors involving Ki-67 and PCNA, diminished oxidative indicators such as MDA and MPO, and augmented the activity of antioxidant markers, notably SOD and CAT. Canagliflozin might alleviate the imiquimod-induced animal model of psoriasis, probably thanks to its profound anti-inflammatory, antioxidant, antiangiogenic, and antiproliferative activities.

Spectrum of Skin Diseases among Inmates in a Nigerian Correctional Centre in Southern Nigeria.

BACKGROUND: Cutaneous morbidities are not uncommon in correctional centres and environmental cleanliness and sanitation practices influence their prevalence and pattern. Overcrowding and poor living conditions are common in correctional facilities and may increase the prevalence of skin diseases amongst inmates. This study aimed to determine the prevalence and pattern of dermatoses in a correctional centre in southern Nigeria. MATERIALS AND METHODS: The study was an institutional-based cross-sectional descriptive study carried out during a health outreach to the facility involving inmates of a correctional centre in southern Nigeria. Using a purpose-designed questionnaire, sociodemographic data containing information on sex, age, prison status, and number of inmates per room was obtained from a total of 252 inmates who consented to the study. They were subsequently clinically examined for skin diseases. Dermatological tools like dermoscopes were used to boost diagnostic accuracy where expedient. All data collected were subsequently analysed using SPSS version 23.0. RESULTS: The prevalence of cutaneous morbidities amongst the inmates was 224(88.9%). A total of 332 skin morbidities were observed in 224 prison inmates with a ratio of 1.5:1 per affected inmate. The common dermatoses encountered in our study were scabies 181(71.8%), bedbugs 38(15.1%), dermatophytosis 24(9.5%), pityriasis versicolor 20(7.9%), and pediculosis 18(7.1%) in a decreasing order of frequency. CONCLUSION: Cutaneous morbidities are common among prison inmates in southern Nigeria. Scabies was the most common dermatoses observed.

CONTEXTE: Les morbidités cutanées ne sont pas rares dans les centres pénitentiaires et les pratiques d'hygiène et d'assainissement de l'environnement influencent leur prévalence et leur répartition. Le surpeuplement et les mauvaises conditions de vie sont courants dans les établissements pénitentiaires et peuvent augmenter la prévalence des maladies de la peau chez les détenus. Cette étude visait à déterminer la prévalence et la répartition des dermatoses dans un centre pénitentiaire nigérian du sud du. MÉTHODES: Il s'agissait d'une étude descriptive transversale institutionnelle réalisée lors d'une campagne de santé dans l'établissement, impliquant des détenus d'un centre pénitentiaire du sud du Nigeria. À l'aide d'un questionnaire spécialement conçu, des données sociodémographiques contenant des informations sur le sexe, l'âge, le statut pénitentiaire et le nombre de détenus par cellule ont été recueillies auprès de 252 détenus ayant donné leur consentement à l'étude. Ils ont ensuite été examinés cliniquement pour les maladies cutanées. Des outils dermatologiques comme les dermoscopes ont été utilisés pour améliorer la précision du diagnostic lorsque cela était nécessaire. Toutes les données collectées ont été analysées à l'aide de SPSS version 23.0. RÉSULTATS: La prévalence des morbidités cutanées chez les détenus était de 224 (88,9 %). Un total de 332 morbidités cutanées ont été observées chez 224 détenus, soit un ratio de 1,5 : 1 par détenu atteint. Les dermatoses les plus fréquentes observées dans notre étude étaient la gale (181, 71,8 %), les punaises de lit (38, 15,1 %), la dermatophytose (24, 9,5 %), le pityriasis versicolor (20, 7,9 %) et la pédiculose (18, 7,1 %) dans l'ordre décroissant de fréquence. CONCLUSION: Les morbidités cutanées sont fréquentes chez les détenus du sud du Nigeria. La gale était la dermatose la plus fréquente observée. MOTS-CLÉS: Dermatoses, Centre pénitentiaire, Gale.

Current Treatments for Generalized Pustular Psoriasis: A Narrative Summary of a Systematic Literature Search.

Generalized pustular psoriasis (GPP) is a rare, chronic and potentially life-threatening autoinflammatory skin disease characterized by widespread eruption of sterile pustules, with or without systemic inflammation. GPP can significantly reduce patients' quality of life (QoL). Several therapeutic approaches have been described in the literature, but there is no consensus on optimal treatment. In this review, we summarize published literature on efficacy, safety and QoL outcomes associated with current treatment of GPP with both approved and non-approved products. Embase and MEDLINE databases were searched (1980-September 2023). A search protocol was designed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and registered on the PROSPERO database (CRD42021215437). Details on publication, population, intervention, efficacy, safety and QoL were captured and checked by independent reviewers. In total, 118 publications were included, with only 19% of publications reporting on the results of clinical trials. Treatment modalities reported for GPP included non-biologic systemic therapies such as retinoids, cyclosporine and methotrexate, topical agents, biologics and small molecules, among others. Results were highly heterogeneous and methodological quality was very low, with only the interleukin-36R inhibitor spesolimab reporting results from placebo-controlled randomized trials; based on this, spesolimab is now approved for GPP treatment in regions including the USA, Japan, China, the EU and several other countries. Some other biologics are approved exclusively in Japan and Taiwan for the treatment of GPP based on open-label studies with small patient numbers in lieu of double-blind studies. Non-standardization of clinical outcomes across studies remains a major hurdle in reaching a consensus on optimal treatment. However, recently trials have been conducted using well-defined, disease-specific endpoints to evaluate GPP-targeted treatments, which will hopefully advance patient care. In conclusion, this review highlights the need for prospective randomized studies with GPP-specific endpoints to determine the optimal treatment strategy.

Generalized pustular psoriasis (GPP) is a rare, chronic skin condition characterized by painful, sterile pustules that can occur all over the body. These pustules may also be accompanied by systemic inflammation, which can lead to serious health complications. GPP significantly impacts patients' quality of life and can even be life-threatening. Because the disease is so rare, treatment guidelines have typically been based on those for plaque psoriasis. However, these guidelines do not specifically address the unique needs of GPP. In this review, we analysed the published literature on GPP management, focussing on treatment efficacy, safety and quality of life outcomes. We searched the literature databases Embase and MEDLINE for articles published between 1980 and September 2023. In total, we identified 118 publications on this topic, covering a wide range of therapies; only one of these therapies, spesolimab, reported results from placebo-controlled randomized trials. Based on these trials, spesolimab is now approved for GPP treatment in the USA, Japan, China, the EU and several other countries. Some other therapies are approved exclusively in Japan and Taiwan based on small, open-label studies in the absence of higher-quality data. To date, comparing treatments has been challenging because of different clinical outcomes used to measure effectiveness. However, well-defined endpoints specific to GPP have recently been developed and used in trials. In conclusion, our review highlights the need for prospective randomized studies with GPP-specific endpoints to determine the best treatment strategy.

Cold urticaria in tropics: A clinico-epidemiological study from North India.

Background Cold urticaria (ColdU) is classified as a subtype of chronic inducible urticaria characterised by recurring pruritic wheals and/or angioedema upon exposure to cold stimuli. However, very limited data is available on ColdU specifically among Indians. Objectives The aim of this study was to describe the clinico-epidemiological characteristics and treatment response in North Indian patients diagnosed with ColdU. Materials and Methods The clinical records of patients diagnosed with ColdU past 5 years (January 2018 to December 2022) were retrospectively reviewed. Data including patient demographics, clinical manifestations, comorbidities, laboratory findings, and treatment response were collected and analysed. Results Among the 1780 urticaria patients included in our study, only 15 cases of cold-induced urticaria were identified. ColdU was classified as typical in all but three patients. The mean age of affected individuals was 36 ± 18 years (20-65 years) and eight patients (53.3%) were males. Mean disease duration at presentation was 18 ± 27 months (3 months-4 years). Two patients experienced cold-induced angioedema and one patient had hypotensive episodes following cold exposure. Twelve patients demonstrated positive results in the ice cube provocation test. Of 15, only 6 (40%) achieved complete control of symptoms with standard dosing of second generation anti-histamines while six patients (40%) required titration to higher doses and three patients (20%) were initiated on cyclosporine therapy, resulting in remission. Limitations Retrospective study design and possibility of selection bias. Conclusion Due to India's predominantly tropical climate, ColdU prevails at lower levels compared to the western regions. ColdU is likely underdiagnosed in India, possibly dismissed as chronic spontaneous urticaria. The management of ColdU involves a combination of protective measures against cold exposure and the use of anti-histamines to control disease activity. This retrospective study provides valuable insights into the clinico-epidemiological characteristics and treatment response of north Indian patients with ColdU.

Discoloration and Dilemma: A Case Report of Hand-Foot Syndrome Associated With Capecitabine Use.

This case highlights the occurrence of hand-foot syndrome due to the use of an antimetabolite group of drugs, capecitabine, which was used in the chemotherapy of a 56-year-old male patient who was diagnosed with rectosigmoid carcinoma. The patient was diagnosed with rectosigmoid carcinoma two months ago and underwent laparoscopic lower anterior resection and colorectal anastomosis. Subsequently, the patient commenced chemotherapy treatment with a combination of oxaliplatin and capecitabine. The patient presented to us with complaints of loose stools for the past three days, and discoloration of the palms, soles, and tongue was noted and subjected to a biopsy, which revealed features compatible with chronic, nonspecific dermatitis. The occurrence of such palmar-plantar erythrodysesthesia with capecitabine is yet to be extensively studied.

UVB-induced TRPS1 regulates MITF transcription activity to promote skin pigmentation.

Hyperpigmented dermatoses are characterized by increased skin pigmentation caused by genetic, environmental factors and inflammation, which lasts a long time and is difficult to treat. Ultraviolet (UV), especially ultraviolet B (UVB), is the primary external factor inducing skin pigmentation. However, the specific regulatory mechanisms are not fully understood. Through analysis of GEO datasets from four UV-exposed skin cell/tissue samples, we found that TRPS1 is the only gene differentially expressed in multiple datasets (GSE22083, GSE67098 and GSE70280) and highly positively correlated with the expression of key melanogenesis genes. Consistently, we observed that TRPS1 is highly expressed in sun-exposed skin tissues compared to non-exposed skin. Additionally, the expression of TRPS1 was also significantly upregulated after UVB irradiation in isolated skin tissues and melanocytes, while knockdown of TRPS1 expression inhibited the UVB-induced melanogenesis. Further research revealed that overexpression of TRPS1 increased melanin content and tyrosinase activity in MNT1 cells, as well as upregulated the expression levels of key melanogenesis genes (MITF, TYR, TYRP1, DCT). In contrast, inhibition of TRPS1 expression showed the opposite effect. Moreover, we found that TRPS1 can bind to the promoter region of MITF, inhibiting the expression of MITF can antagonize the melanogenesis induced by TRPS1. In conclusion, UVB-induced TRPS1 promotes melanogenesis by activating the transcriptional activity of MITF.