Exposure factors in the occurrence and development of melasma (Review).

Melasma is an acquired pigmentation disease that mainly involves the development of symmetrical yellow-brown facial patches. The incidence rate of the disease is increasing yearly. Therefore, actively studying the exposure factors that induce melasma could contribute to the prevention and treatment of this disease. In the present review, the possible exposure factors were summarized.

Perioperative Practices in Dermatologic Surgery.

BACKGROUND: Mohs micrographic surgery is generally safe and well tolerated. Various perioperative practices are employed with the aim of reducing adverse events; however, implementation is variable, and limited efficacy data are available. OBJECTIVE: This study sought to assess perioperative practice patterns among dermatologic surgeons with regards to antibiotic prophylaxis (AP), anticoagulation, activity restrictions, and antiseptic choice. METHODS AND MATERIALS: Two surveys were distributed by the American College of Mohs Surgery (ACMS) and the American Society for Mohs Surgery (ASMS) to their membership via email. RESULTS: One hundres seventy-seven surgeons participated, with membership from ACMS (61%), ASMS (35%), or both organizations (4%) represented. Systemic AP is prescribed preoperatively by 96% (162/168) and postoperatively by 91% (161/177) of surgeons for variable clinical indications. Therapeutic antiplatelet and anticoagulant medications are rarely held (3%-5%, 4-7/149), whereas preventative aspirin (30%, 45/149), NSAIDs (25%, 36/145), and supplements known to have an anticoagulant effect (54%, 80/149) are more commonly held. Antiseptic choice and recommended activity restrictions vary. CONCLUSION: Perioperative practices of dermatologic surgeons are variable and, where applicable, may deviate from guidelines. These findings underscore the need for standardization and updated guidelines for perioperative practices in dermatologic surgery.

Distance learning in the era of COVID-19.

The novel coronavirus (SARS-CoV-2) pandemic has necessitated a dramatic shift in how our dermatology residents and fellows are educated. Distance or online learning has become the norm, and several national and international academic societies have combined resources to assure that continuing medical education occurs during this difficult time. The purpose of this communication is to review select online resources available to dermatology trainees and to encourage our colleagues to continue to advance our specialty through distance learning.

A retrospective review of 93 cases of cellular dermatofibromas.

BACKGROUND: Cellular dermatofibromas (CDF) are an uncommon variant of benign fibrous histiocytomas with propensity to recur and rarely metastasize as well as demonstrate histologic similarities to more dangerous lesions. OBJECTIVES: The aim of this present study was to further describe the presentation and outcome of the cellular variant of benign fibrous histiocytomas so that it can be diagnosed and treated appropriately. METHODS: A retrospective chart review was performed on all patients seen in a single hospital system in Detroit, Michigan, from 2007 to 2017. CDF was confirmed by pathology. Baseline demographics, specialty service of diagnosis and treatment, treatment modality, and outcome were collected. RESULTS: Of the 93 qualifying patients, the average age at diagnosis was 42.65 years. The most common specialty service that diagnosed and treated patients was dermatology (38.71%). About 95.0% of CDF stained positive for Factor 13A (19/20), and 90.48% were CD34 negative (19/21). Of patients, 33.33% had recurrences of their CDF (9/27). Two patients had three or more recurrences. One patient's death was attributed to the CDF. CONCLUSION: CDF have a high local recurrence rate and similarities to more dangerous and malignant lesions. Patients with cellular dermatofibromas present to many subspecialty services for diagnosis and should be treated aggressively.

Review of environmental effects of oxybenzone and other sunscreen active ingredients.

With increasing awareness regarding the risks of sunburn, photoaging, and skin cancer, the use of sunscreens has increased. Organic and inorganic filters are used in sunscreen products worldwide. Concerns have been raised regarding the environmental effects of commonly used organic ultraviolet (UV) filters, including oxybenzone (benzophenone-3), 4-methylbenzylidene camphor, octocrylene, and octinoxate (ethylhexyl methoxycinnamate). Studies have identified UV filters such as oxybenzone, octocrylene, octinoxate, and ethylhexyl salicylate in almost all water sources around the world and have commented that these filters are not easily removed by common wastewater treatment plant techniques. Additionally, in laboratory settings, oxybenzone has been implicated specifically as a possible contributor to coral reef bleaching. Furthermore, UV filters such as 4-methylbenzylidene camphor, oxybenzone, octocrylene, and octinoxate have been identified in various species of fish worldwide, which has possible consequences for the food chain. As dermatologists, it is important for us to continue to emphasize the public health impact of excessive sun exposure and advise our patients about proper photoprotection practice, which consists of seeking shade, wearing photoprotective clothing (including hats and sunglasses), and applying appropriate sunscreens.

A review of inorganic UV filters zinc oxide and titanium dioxide.

Photoprotection has become integral in the prevention of keratinocyte cancer and photoaging. Organic ultraviolet (UV) filters such as oxybenzone and octinoxate have become controversial due to their potential impact on the environmental and their potential human health risks. As such, inorganic UV filters, zinc oxide (ZnO) and titanium dioxide (TiO2 ), have become paramount in discussions about photoprotection. ZnO and TiO2 are used in sunscreens as nanoparticles, which denotes a size <100 nm. The smaller size of these mineral particles increases their cosmetic acceptability by users as they are much less visible after application. ZnO has a broad UVA-UVB absorption curve, while TiO2 provides better UVB protection. Overall, the human health risks with inorganic filters are extremely low given a lack of percutaneous absorption; however, there is potential risk when exposed via inhalation, prompting recommendations against spray sunscreen products with nanoparticles. At this time, the known risk to the environment is low though the risk stratification may evolve with increasing usage of these filters and higher environmental concentrations. The continued practice of photoprotection is critical. The public should be counseled to seek shade, use photoprotective clothing including hats and glasses in addition to sunscreens on sun-exposed skin. For those concerned about emerging evidence of environmental impact of organic UV filters, based on current evidence, ZnO and TiO2 -containing sunscreens are safe alternatives.

Emerging imaging technologies in dermatology: Part II: Applications and limitations.

Clinical examination is critical for the diagnosis and identification of response to treatment. It is fortunate that technologies are continuing to evolve, enabling augmentation of classical clinical examination with noninvasive imaging modalities. This article discusses emerging technologies with a focus on digital photographic imaging, confocal microscopy, optical coherence tomography, and high-frequency ultrasound, as well as several additional developing modalities. The most readily adopted technologies to date include total-body digital photography and dermoscopy, with some practitioners beginning to use confocal microscopy. In this article, applications and limitations are addressed. For a detailed discussion of the principles involved in these technologies, please refer to the first part of this review article.

Emerging imaging technologies in dermatology: Part I: Basic principles.

Dermatologists rely primarily on clinical examination in combination with histopathology to diagnose conditions; however, clinical examination alone might not be sufficient for accurate diagnosis and skin biopsies have associated morbidity. With continued technological advancement, there are emerging ancillary imaging technologies available to dermatologists to aid in diagnosis and management. This 2-part review article will discuss these emerging technologies including: digital photographic imaging, confocal microscopy, optical coherence tomography, and high-frequency ultrasound, as well as several additional modalities in development. In this first installment, the authors describe the breadth of technologies available and the science behind them. Then, in the second article, the authors discuss the applications and limitations of these technologies and future directions.

Cutaneous manifestations of metastatic Crohn's disease.

Metastatic Crohn's disease is a rare cutaneous complication of primary Crohn's disease. It is a granulomatous inflammatory process, similar to the pathogenic mechanism of Crohn's disease, that occurs in sites discontiguous from the gastrointestinal tract. Metastatic Crohn's disease can precede the development of Crohn's disease by months to years, and children are more likely to present with metastatic Crohn's disease in the absence of gastrointestinal symptoms. Given that approximately 30% of individuals with Crohn's disease present in childhood, early recognition of extraintestinal manifestations of Crohn's disease such as metastatic Crohn's disease can aid in timely diagnosis and management of bowel disease. We present data from two pediatric cases of metastatic Crohn's disease recently seen at our institution in addition to the 61 reported cases of pediatric metastatic Crohn's disease in the literature. This review article will focus on the epidemiology, pathogenesis, clinical features, and histology of and treatment options for pediatric metastatic Crohn's disease.

Clinical, dermoscopic, and pathologic features of onychopapilloma: A review of 47 cases.

BACKGROUND: Onychopapilloma is a benign neoplasm of the nail bed and the distal matrix. Although not uncommon in our experience, only up to 32 cases of this tumor have been reported in the literature. OBJECTIVE: We sought to review the clinical, dermoscopic, and pathologic features of onychopapilloma. METHODS: We retrospectively analyzed the clinical features of 47 patients with pathologically confirmed onychopapilloma diagnosed within the last 5 years, and reviewed the published literature. RESULTS: The most common clinical presentation was longitudinal erythronychia (n = 25); followed by longitudinal leukonychia (n = 7); longitudinal melanonychia (n = 4); long splinter hemorrhages without erythronychia, leukonychia, or melanonychia (n = 8); and short splinter hemorrhages without erythronychia, leukonychia, or melanonychia (n = 3), with subungual mass (n = 47) and distal fissuring (n = 11). Pathology was consistent with acanthosis of the nail bed and distal matrix, with matrix metaplasia underlying distal subungual hyperkeratosis. LIMITATIONS: This was a retrospective analysis. CONCLUSION: To our knowledge, our series of onychopapilloma is the largest so far. Among various clinical presentations, longitudinal erythronychia is the most common. Dermoscopy of the free edge of the nail plate showing a small subungual keratotic mass where the band reaches the nail plate margin provides a clue for the diagnosis.

Tips to diagnose uncommon nail disorders.

This article reviews 6 nail disorders that, although easy to diagnose, are misdiagnosed frequently by dermatologists and general practitioners. Diagnostic clues are emphasized to familiarize readers with features that indicate the correct diagnosis. We focus on two common tumors (onychomatricoma and onychopapilloma), two rare genetic conditions that can be diagnosed owing to nail changes (Darier disease and nail patella syndrome), and two uncommon acquired disorders (the yellow nail syndrome and lichen striatus).

Do inflammatory pathways drive melanomagenesis?

Inflammatory pathways serve to protect the host and promote tissue healing/repair; however, over-activation or dysregulation can be pathological with unintended consequences including malignant progression. A correlation between inflammation and cancer has been well established, and anti-inflammatory medications have been shown to be chemopreventive in certain malignancies. Data are now becoming available that outline an inflammatory pathway that may have a critical role in melanomagenesis. ATP-regulated membrane channels/receptors P2X7 and PANX1 have been directly implicated in melanoma tumor growth. Among other potential effects, opening of the P2X7/PANX1 channel results in activation of the NALP3 inflammasome, which in turn leads to caspase-1 activation and increased levels of activated IL-1ß. Elevated levels of caspase-1 and IL-1ß have been correlated with melanoma progression, and inhibitors of the inflammasome, caspase and IL-1ß activity have all been shown to inhibit melanoma growth. Among many other potential actions, IL-1ß increases cyclooxygenase-2 expression leading to local increases in inflammatory mediators such as prostaglandin E2 (PGE2). Anti-inflammatory medications targeting the end of this pathway have had positive results for certain cancers but overall remain mixed for melanoma. A better understanding of the pathways and appropriate intervention points may help direct future therapies. In this viewpoint, we will review data and attempt to model an inflammatory pathway that may be critical for melanomagenesis and propose future directions for exploration.

How, and from which cell sources, do nevi really develop?

Melanocytic neoplasms are a diverse group of benign and malignant tumors with variable clinical features. While some models still promote the epidermal melanocyte as the origin of melanocytic neoplasms, clinical findings are inconsistent with this theory for the majority of tumors. Despite advances in naevus and melanoma biology, the location and differentiation status of the cell of origin remains undefined. Germ line genetics, biological state and cellular location of the mutated cell, as well as local environmental factors all likely play a role in the development of melanocytic neoplasms. Herein, we will review potential models for melanocytic neoplasia and discuss research challenges and opportunities.