New Insights into the Role of PPARγ in Skin Physiopathology.

Peroxisome proliferator-activated receptor gamma (PPARγ) is a transcription factor expressed in many tissues, including skin, where it is essential for maintaining skin barrier permeability, regulating cell proliferation/differentiation, and modulating antioxidant and inflammatory responses upon ligand binding. Therefore, PPARγ activation has important implications for skin homeostasis. Over the past 20 years, with increasing interest in the role of PPARs in skin physiopathology, considerable effort has been devoted to the development of PPARγ ligands as a therapeutic option for skin inflammatory disorders. In addition, PPARγ also regulates sebocyte differentiation and lipid production, making it a potential target for inflammatory sebaceous disorders such as acne. A large number of studies suggest that PPARγ also acts as a skin tumor suppressor in both melanoma and non-melanoma skin cancers, but its role in tumorigenesis remains controversial. In this review, we have summarized the current state of research into the role of PPARγ in skin health and disease and how this may provide a starting point for the development of more potent and selective PPARγ ligands with a low toxicity profile, thereby reducing unwanted side effects.

Dermatological changes in a prospective cohort of acutely ill, hospitalised Malawian children, stratified according to nutritional status.

RATIONALE: Since the first documentation of skin changes in malnutrition in the early 18th century, various hair and skin changes have been reported in severely malnourished children globally. We aimed to describe the frequency and types of skin conditions in children admitted with acute illness to Queen Elizabeth Central Hospital, Blantyre, Malawi across a spectrum of nutritional status and validate an existing skin assessment tool. METHODS: Children between 1 week and 23 months of age with acute illness were enrolled and stratified by anthropometry. Standardised photographs were taken, and three dermatologists assessed skin changes and scored each child according to the SCORDoK tool. RESULTS: Among 103 children, median age of 12 months, 31 (30%) had severe wasting, 11 (11%) kwashiorkor (nutritional oedema), 20 (19%) had moderate wasting, 41 (40%) had no nutritional wasting and 18 (17%) a positive HIV antibody test. Six (5.8%) of the included patients died. 51 (50%) of children presented with at least one skin change. Pigmentary changes were the most common, observed in 35 (34%), with hair loss and bullae, erosions and desquamation the second most prevalent skin condition. Common diagnoses were congenital dermal melanocytosis, diaper dermatitis, eczema and postinflammatory hyperpigmentation. Severe skin changes like flaky paint dermatosis were rarely identified. Inter-rater variability calculations showed only fair agreement (overall Fleiss' kappa 0.25) while intrarater variability had a fair-moderate agreement (Cohen's kappa score of 0.47-0.58). DISCUSSION: Skin changes in hospitalised children with an acute illness and stratified according to nutritional status were not as prevalent as historically reported. Dermatological assessment by means of the SKORDoK tool using photographs is less reliable than expected.

Cutaneous Rosai-Dorfman disease: a systematic review and reappraisal of its treatment and prognosis.

Cutaneous Rosai Dorfman disease (CRDD) is a rare histiocytic disorder that shows distinctive clinical presentation and prognosis. Sufficient data is currently lacking regarding evidence-based management of CRDD. This systematic review aims to provide a comprehensive overview of CRDD, focusing on treatment approaches and outcomes. PubMed and Scopus databases were searched for studies on CRDD from June 1st, 2013 to May 31st, 2023. Articles describing cases of CRDD confirmed with histological examination were eligible for inclusion. All interventions for CRDD were analyzed. The primary outcome measure was the response of cutaneous lesions to treatment including complete response (CR), partial response (PR), and no response. The secondary outcome measures were mortality rate, relapse rate, and the occurrence of adverse events related to CRDD treatment. Eighty-seven articles describing 118 CRDD cases were included. The mean age was 48.2±16.8 years. The sex ratio (F/M) was 1.53. Nodular (46.6%) erythematous (45.3%) lesions, located on the face (38.1%) were the most prevalent presentations. Associated hematological malignancies were noted in 8 (6.8%) cases. Surgical excision was the most prevalent intervention (51 cases) with CR in 48 cases. Systemic corticosteroids were used in 32 cases with 20 CR/PR, retinoids in 10 cases with 4 CR/PR, thalidomide in 9 cases with 5 CR/PR, methotrexate in 8 cases with 7 CR/PR while observation was decided in 10 cases with 6 CR/PR. Factors independently associated with the absence of response to treatment were facial involvement (OR = 0.76, p = 0.014), and cutaneous lesion size (OR = 1.016, p = 0.03). This systematic review shows distinctive clinical characteristics of CRDD and provides insights into the appropriate management of the disease. It allowed a proposal of a treatment algorithm that should be interpreted in the context of current evidence and would help practitioners in treating this rare disease.

Signatures of epigenetic, biological and mitotic age acceleration and telomere shortening are associated with arsenic-induced skin lesions.

Chronic arsenic exposure is a global health hazard significantly associated with the development of deleterious cutaneous changes and increased keratinocyte cancer risk. Although arsenic exposure is associated with broad-scale cellular and molecular changes, gaps exist in understanding how these changes impact the skin and facilitate malignant transformation. Recently developed epigenetic "clocks" can accurately predict chronological, biological and mitotic age, as well as telomere length, on the basis of tissue DNA methylation state. Deviations of predicted from expected age (epigenetic age dysregulation) have been associated with numerous complex diseases, increased all-cause mortality and higher cancer risk. We investigated the ability of these algorithms to detect molecular changes associated with chronic arsenic exposure in the context of associated skin lesions. To accomplish this, we utilized a multi-algorithmic approach incorporating seven "clocks" (Horvath, Skin&Blood, PhenoAge, PCPhenoAge, GrimAge, DNAmTL and epiTOC2) to analyze peripheral blood of pediatric and adult cohorts of arsenic-exposed (n = 84) and arsenic-naïve (n = 33) individuals, among whom n = 18 were affected by skin lesions. Arsenic-exposed adults with skin lesions exhibited accelerated epigenetic (Skin&Blood: + 7.0 years [95% CI 3.7; 10.2], q = 6.8 × 10-4), biological (PhenoAge: + 5.8 years [95% CI 0.7; 11.0], q = 7.4 × 10-2, p = 2.8 × 10-2) and mitotic age (epiTOC2: + 19.7 annual cell divisions [95% CI 1.8; 37.7], q = 7.4 × 10-2, p = 3.2 × 10-2) compared to healthy arsenic-naïve individuals; and accelerated epigenetic age (Skin&Blood: + 2.8 years [95% CI 0.2; 5.3], q = 2.4 × 10-1, p = 3.4 × 10-2) compared to lesion-free arsenic-exposed individuals. Moreover, lesion-free exposed adults exhibited accelerated Skin&Blood age (+ 4.2 [95% CI 1.3; 7.1], q = 3.8 × 10-2) compared to their arsenic-naïve counterparts. Compared to the pediatric group, arsenic-exposed adults exhibited accelerated epigenetic (+ 3.1 to 4.4 years (95% CI 1.2; 6.4], q = 2.4 × 10-4-3.1 × 10-3), biological (+ 7.4 to 7.8 years [95% CI 3.0; 12.1] q = 1.6 × 10-3-2.8 × 10-3) and mitotic age (+ 50.0 annual cell divisions [95% CI 15.6; 84.5], q = 7.8 × 10-3), as well as shortened telomere length (- 0.23 kilobases [95% CI - 0.13; - 0.33], q = 2.4 × 10-4), across all seven algorithms. We demonstrate that lifetime arsenic exposure and presence of arsenic-associated skin lesions are associated with accelerated epigenetic, biological and mitotic age, and shortened telomere length, reflecting altered immune signaling and genomic regulation. Our findings highlight the usefulness of DNA methylation-based algorithms in identifying deleterious molecular changes associated with chronic exposure to the heavy metal, serving as potential prognosticators of arsenic-induced cutaneous malignancy.

Gammopathic dermopathy: characterization of cutaneous MGUS.

Monoclonal Gammopathy of Undetermined Significance (MGUS) is a clonal plasma cell disorder that is considered preneoplastic, asymptomatic, and only requiring observation. However, MGUS may result in cutaneous complications, which are poorly understood, causing treatment delays and patient suffering. We present 30 patients with cutaneous findings associated with MGUS, characterizing clinical presentations, isoforms, treatments, and outcomes. These included: MGUS-associated 'rashes' (pruritic eczematous rashes), reactive and mucin-depositional conditions (pyoderma gangrenosum, scleromyxedema), M-protein-related deposition disorders (POEMS syndrome, Waldenstrom macroglobulinemia), and cutaneous lymphomas. Twelve of 30 (40%) patients received multiple myeloma drugs (MMDs). Eleven (92%) patients improved, and those not receiving MMDs rarely improved, suggesting that MMDs have efficacy for cutaneous manifestations of MGUS. Therefore, trialing MMDs may be warranted for patients with MGUS not responding to other therapies. Moreover, evaluation for monoclonal gammopathy in elderly patients with intractable pruritus or other chronic skin conditions that are non-responsive to skin-directed therapies should be considered.

Punch Biopsy Extraction With Fingers.

Punch biopsies are commonly used in dermatology for diagnosing skin diseases. Traditional methods involve the use of forceps, skin hooks, and scissors, which add to health care costs. The technique described here offers a cost-effective and efficient alternative for obtaining specimens.

A Protocol for the Automated Assessment of Cutaneous Pathology in a Mouse Model of Hemichannel Dysfunction.

In this chapter, we provide detailed instructions to perform quantitative reflectance imaging in a mouse model of a rare epidermal disorder caused by hyperactive connexin 26 hemichannels. Reflectance imaging is a versatile and powerful tool in dermatology, offering noninvasive, high-resolution insights into skin pathology, which is essential for both clinical practice and research. This approach offers several advantages and applications. Unlike traditional biopsy, reflectance imaging is noninvasive, allowing for real-time, in vivo examination of the skin. This is particularly valuable for monitoring chronic conditions or assessing the efficacy of treatments over time, enabling the detailed examination of skin morphology. This is crucial for identifying features of skin diseases such as cancers, inflammatory conditions, and infections. In therapeutic applications, reflectance imaging can be used to monitor the response of skin lesions to treatments. It can help in identifying the most representative area of a lesion for biopsy, thereby increasing the diagnostic accuracy. Reflectance imaging can also be used to diagnose and monitor inflammatory skin diseases, like psoriasis and eczema, by visualizing changes in skin structure and cellular infiltration. As the technology becomes more accessible, it has potential in telemedicine, allowing for remote diagnosis and monitoring of skin conditions. In academic settings, reflectance imaging can be a powerful research tool, enabling the study of skin pathology and the effects of novel treatments, including the development of monoclonal antibodies for therapeutic applications.

Cutaneous crystal storing histiocytosis: A case series with review of literature.

Crystal-storing histiocytosis (CSH) is a rare condition in which crystals accumulate in the cytoplasm of histiocytes and is usually associated with a lymphoplasmacytic neoplasm. Cutaneous CSH is extraordinarily rare and limited to case reports in the literature. We report two cases of this disease with cutaneous involvement. Case 1 was a 65-year-old male with a 4-month history of a pruritic eruption that started as a solitary pink to skin-colored indurated plaque on the anterior neck before progressing to involve the whole neck, chest wall, and face. Case 2 was a 54-year-old woman with a history of unspecified "lymphoma" who presented with a soft nodule on the forearm. Biopsies from both cases had similar findings and showed a proliferation of epithelioid cells with pink cytoplasm and intracellular crystalline structures infiltrating the dermis and subcutaneous fat. In the first case, the cells were positive for CD43, CD45, CD68, and IgG kappa, and in the second case, the crystals were positive for IgG lambda. Based on these findings, the patients were diagnosed with cutaneous CSH. We highlight this rare diagnosis and the importance of investigating an underlying lymphoplasmacytic neoplasm.

Congenital localized cutaneous Langerhans cell histiocytosis in a Holstein calf.

Distinct solitary dermal nodules, either covered by an alopecic, or sometimes ulcerated, epidermis, were noticed on the head of a stillborn Holstein calf. The head was submitted for autopsy, and the nodules were found to consist of homogeneous, diffuse pale-yellow, soft-tissue masses with distinct margins that elevated the epidermis above the adjacent skin. Histologically, the dermal nodules were well-delineated on the deep margin approaching the cutaneous muscle and consisted of perivascular neoplastic infiltrates of round cells that in some places coalesced into sheets that extended into the dermis and subcutis. Neoplastic cells separated adnexa and collagen. Immunohistochemistry revealed intense tumor cell expression of vimentin, Iba1, E-cadherin, and CD204; expression of CD18 was faint. The masses were diagnosed as Langerhans cell histiocytosis. Congenital cutaneous Langerhans cell histiocytosis has not been reported previously in cattle, to our knowledge, and should be included in the differential diagnosis of congenital nodular skin lesions.

[Research progresses on acute skin failure in children].

Acute skin failure (ASF) is an inevitable damage to the skin and subcutaneous tissue caused by hemodynamic instability and/or low perfusion. At present, there are some understandings and reports about adult ASF at home and abroad, but there are few reports about children's ASF. This article reviewed the definition, pathophysiological changes, risk factors, clinical manifestations, and management of children's ASF, and put forward suggestions in order to provide ideas for clinical diagnosis and treatment of children's ASF, and promote the further study of children's ASF.

[Research advances on the role of aerobic glycolysis in skin fibrosis diseases].

Skin fibrosis diseases mainly include hypertrophic scar, keloid, and systemic sclerosis, etc. The main pathological features are excessive activation of fibroblasts and abnormal deposition of extracellular matrix. In recent years, studies have shown that aerobic glycolysis is closely related to the occurrence and development of skin fibrosis diseases. Drugs targeting aerobic glycolysis has provided new ideas for skin anti-fibrosis treatment. This article reviews the role of enzymes and products related to aerobic glycolysis in the occurrence and development of skin fibrosis diseases and the drugs targeting aerobic glycolysis for the treatment of skin fibrosis diseases.

The role of thymic stromal lymphopoietin in cutaneous disorders.

Thymic Stromal Lymphopoietin (TSLP) is an important cytokine that invokes early immune responses. TSLP, an IL-7-like cytokine encoded by the TSLP gene, activates JAK1 and JAK2 signaling pathways, stimulating dendritic cells to induce inflammatory Th2 cells. This cytokine is associated with pruritus in various cutaneous disorders, particularly atopic dermatitis. Varying levels of the cytokine TSLP have been demonstrated in studies of different cutaneous disorders. Pharmacological treatment targeting TSLP has been explored recently, particularly in the realm of atopic dermatitis.This review explores the relation of TSLP to cutaneous diseases, highlighting its potential as a biomarker for monitoring disease progression in discoid lupus erythematosus (DLE). The pharmacological therapy involving TSLP is discussed, along with the potential role of TSLP promotion in the treatment of alopecia areata. This overview examines the background, structure, and functions of TSLP, with a focus on its association with cutaneous disorders and a special focus on the impact of the atopic march.

Microblading reaction as a manifestation of systemic sarcoidosis: two case reports and a review of the literature.

BACKGROUND: Sarcoidosis is a multisystemic disease characterized by granulomatous inflammation. Sarcoidosis often poses a diagnostic challenge owing to its nonspecific or mild clinical features. In 20-35% of cases, sarcoidosis initially presents on skin. However, skin lesions commonly mimic dermatological conditions. Therefore, it is important to not underestimate the skin manifestations and perform histopathological examinations to make a timely diagnosis. CASE PRESENTATION: We present two cases of 33-year-old Caucasian female patients with orange-red macules and plaques that developed in the eyebrow area 1 and 6 years after microblading, respectively. Histopathological examination confirmed a diagnosis of sarcoidosis. The lymph nodes and lungs were also affected in both patients. CONCLUSION: Our two reports suggest that an esthetic procedure involving dermal or subcutaneous injection of foreign materials can trigger the development of cutaneous and systemic sarcoidosis. However, this relationship has not been described yet. Physicians should, therefore, be aware of this complication to properly evaluate and treat such patients in a timely manner.

Lymphoplasmocytic plaque in children: A report of an atypical location.

Lymphoplasmocytic plaque in children (LPC) is a rare and distinctive skin disorder primarily affecting the pediatric population. Characterized by its unique histopathological features, the condition manifests as well-defined plaques with a predominance of lymphocytes and plasma cells infiltrating the dermis. Despite its limited prevalence, recognizing this entity is crucial for accurate diagnosis and appropriate management of affected patients. We report the case of a 10-year-old male presenting with LPC in the extensor surface of the upper arm, a rarely reported location, treated with both topical and intralesional corticosteroids resulting in partial improvement.

Immunologic Profiling of Immune-Related Cutaneous Adverse Events with Checkpoint Inhibitors Reveals Polarized Actionable Pathways.

PURPOSE: Immune-related cutaneous adverse events (ircAE) occur in ≥50% of patients treated with checkpoint inhibitors, but the underlying mechanisms for ircAEs are poorly understood. EXPERIMENTAL DESIGN: Phenotyping/biomarker analyses were conducted in 200 patients on checkpoint inhibitors [139 with ircAEs and 61 without (control group)] to characterize their clinical presentation and immunologic endotypes. Cytokines were evaluated in skin biopsies, skin tape strip extracts, and plasma using real-time PCR and Meso Scale Discovery multiplex cytokine assays. RESULTS: Eight ircAE phenotypes were identified: pruritus (26%), maculopapular rash (MPR; 21%), eczema (19%), lichenoid (11%), urticaria (8%), psoriasiform (6%), vitiligo (5%), and bullous dermatitis (4%). All phenotypes showed skin lymphocyte and eosinophil infiltrates. Skin biopsy PCR revealed the highest increase in IFNγ mRNA in patients with lichenoid (P < 0.0001) and psoriasiform dermatitis (P < 0.01) as compared with patients without ircAEs, whereas the highest IL13 mRNA levels were detected in patients with eczema (P < 0.0001, compared with control). IL17A mRNA was selectively increased in psoriasiform (P < 0.001), lichenoid (P < 0.0001), bullous dermatitis (P < 0.05), and MPR (P < 0.001) compared with control. Distinct cytokine profiles were confirmed in skin tape strip and plasma. Analysis determined increased skin/plasma IL4 cytokine in pruritus, skin IL13 in eczema, plasma IL5 and IL31 in eczema and urticaria, and mixed-cytokine pathways in MPR. Broad inhibition via corticosteroids or type 2 cytokine-targeted inhibition resulted in clinical benefit in these ircAEs. In contrast, significant skin upregulation of type 1/type 17 pathways was found in psoriasiform, lichenoid, bullous dermatitis, and type 1 activation in vitiligo. CONCLUSIONS: Distinct immunologic ircAE endotypes suggest actionable targets for precision medicine-based interventions.

Dermoscopy to differentiate clinically similar inflammatory and neoplastic skin lesions.

INTRODUCTION: Over the few last decades, dermoscopy has become an invaluable and popular imaging technique that complements the diagnostic armamentarium of dermatologists, being employed for both tumors and inflammatory diseases. Whereas distinction between neoplastic and inflammatory lesions is often straightforward based on clinical data, there are some scenarios that may be troublesome, e.g., solitary inflammatory lesions or tumors superimposed to a widespread inflammatory condition that may share macroscopic morphological findings. EVIDENCE ACQUISITION: We reviewed the literature to identify dermoscopic clues to support the differential diagnosis of clinically similar inflammatory and neoplastic skin lesions, also providing the histological background of such dermoscopic points of differentiation. EVIDENCE SYNTHESIS: Dermoscopic differentiating features were identified for 12 relatively common challenging scenarios, including Bowen's disease and basal cell carcinoma vs. psoriasis and dermatitis, erythroplasia of Queyrat vs. inflammatory balanitis, mammary and extramammary Paget's disease vs. inflammatory mimickers, actinic keratoses vs. discoid lupus erythematosus, squamous cell carcinoma vs. hypertrophic lichen planus and lichen simplex chronicus, actinic cheilitis vs. inflammatory cheilitis, keratoacanthomas vs. prurigo nodularis, nodular lymphomas vs. pseudolymphomas and inflammatory mimickers, mycosis fungoides vs. parapsoriasis and inflammatory mimickers, angiosarcoma vs granuloma faciale, and Kaposi sarcoma vs pseudo-Kaposi. CONCLUSIONS: Dermoscopy may be of aid in differentiating clinically similar inflammatory and neoplastic skin lesions.

Comparison of organ involvement clusters in Black and White American sarcoidosis patients from a prospectively collected patient registry.

BACKGROUND: Due to the heterogeneity of sarcoidosis, there is a need to define clinical phenotypes to allow for tailoring of clinical care and identification of more homogenous populations to facilitate research. METHODS: We utilized data from a prospectively collected registry of sarcoidosis patients seen at a single quaternary referral center between January 2019 and February 2021. We used multiple correspondence analysis (MCA) and k-means clustering to investigate if the clusters previously identified in the GenPhenReSa study were reproducible in a US population. We also investigated if these clusters were stable when the population was stratified by race. RESULTS: We replicated 3 of the 5 clusters seen in the GenPhenReSa study in our cohort. We likewise identified similar clusters between White and Black patients with sarcoidosis. Differences in organ manifestations associations between White and Black patients were seen primarily in relation to cardiac, neurologic, and ocular involvement. CONCLUSIONS: The organ clusters of liver-spleen, isolated pulmonary, and musculoskeletal-skin were reproducible in a US cohort, and in both Black and White patients.