This "mite" Surprise You: Scabies Masquerading as Langerhans Cell Histiocytosis - A Case Report.

Introduction: Scabies is a common parasitic infestation caused by the mite Sarcoptes scabiei. Scabies can mimic other entities clinically, resulting in misdiagnosis. The presence of a mite in the stratum corneum on biopsy specimens is diagnostic of scabies. However, there are instances when mites are not visible, and immunohistochemical (IHC) staining may be misleading. An example is when IHC demonstrates Cluster of Differentiation 1a and S100 positivity. The main differential diagnosis for this finding is Langerhans cell histiocytosis, a group of idiopathic disorders of bone marrow-derived Langerhans cells, with manifestations ranging from isolated to life-threatening multisystem disease. Case Presentation: We present a case of a patient who was diagnosed with Langerhans cell histiocytosis based on histological findings, further review with a repeat reading and deeper sectioning of her biopsy revealed a mite in the stratum corneum, altering the diagnosis, course, and management. She subsequently developed persistent post-scabietic nodules, an underreported entity that may occur following infestation and persist for up to a year. These lesions are self-limiting and do not require repeated courses of treatment. Conclusion: Langerhans cell hyperplasia may be seen in a multitude of entities, including scabies. Familiarity with this phenomenon is crucial to avoid unnecessary invasive investigations, aggressive management and alleviate patients' concerns.

Efficacy and Safety of Low Fluence Nd:YAG Laser Treatment in Melasma: A Meta-Analysis and Systematic Review.

BACKGROUND: Low-fluence, multisession therapy of Nd:YAG laser has been widely used for treating melasma. OBJECTIVE: To evaluate the efficacy and safety of low-fluence Nd:YAG laser toning for melasma using a systematic review and meta-analysis. METHODS: The PubMed, Web of Science, Embase, and Cochrane Library databases were searched till December 2020. A total of 50 studies (1,772 patients) and 66 studies were selected for the evaluation of the efficacy and complications, retrospectively. RESULTS: The mean Melasma Area and Severity Index/modified Melasma Area and Severity Index scores for laser toning as monotherapy at <4, 4 to <8, 8 to <12, 12 to <24, and ≥24 weeks after treatment compared with that at pretreatment were -0.51, -0.91, -0.97, -0.92, 0.01 SD, whereas those as combination therapy were -1.64, -1.26, -0.94, not available, -1.45 SD, respectively. An increase in light value and a decrease in relative lightness index have remained up to 8 weeks after laser toning. Complications including hypopigmentation/leukoderma, postinflammatory hyperpigmentation, and recurrence were noted. The incidence of hypopigmentation/leukoderma correlated with the number of laser sessions (p = .036). CONCLUSION: Low-fluence Nd:YAG laser toning as combination therapy has shown better efficacy than monotherapy and the efficacy seems to diminish with time. This study suggests the positive correlation of hypopigmentation/leukoderma with the number of laser sessions.

Skin diseases in Asian individuals that you do not want to miss: A selection of unique or relatively more common conditions in Asian populations.

The Asian population currently constitutes a simple majority of the global population, comprising nearly 60%. The percentage of the US population that identifies as Asian is expected to grow to 41 million by the year 2050, making up an eventual 9% of the US population. As the world and US populations of Asian individuals increase, the demand for dermatologic care from this population will increase, requiring dermatologists to become more familiar with the diagnosis and treatment of Asian-specific skin characteristics and diseases. In this contribution, we review skin conditions specific to or relatively more common in Asian patients to help recognition and management of diseases in an increasing Asian patient population. We discuss prurigo pigmentosa, primary cutaneous plasmacytosis, lipodystrophia centrifugalis abdominalis infantilis, Epstein-Barr viru-positive T- and natural killer-cell lymphoproliferative disorders, acquired bilateral nevus of Ota-like macules, and BehÒ«et disease.

Factors Affecting Depth of Penetration in Microneedling- and Laser-Assisted Drug Delivery: The Importance of Timing of Topical Application.

BACKGROUND: Microneedling- and laser-assisted drug delivery are emerging techniques used to treat various conditions. However, key parameters affecting drug penetration remain unknown. OBJECTIVE: This study aims to investigate the importance of timing of topical application, needle length, and device type for drug delivery. MATERIALS AND METHODS: Skin harvested from cosmetic surgeries was treated with black ink applied before or after treatment with a microneedling pen (MP), roller, or fractional ablative CO2 laser, and incubated for different time intervals. Ink penetration was additionally tested using different needle lengths. Sandwich estimator was used for statistical analysis. RESULTS: Ink applied before MP penetrated deeper compared to ink applied afterward at 1 and 3 hours, and roller microneedling in both the ink-before and -after scenarios at 1, 3, and 6 hours (p < .05). Microneedling demonstrated lateral extension of ink beyond microchannels with increased ink penetration over time. CO2 laser demonstrated ink localization within microthermal zones without time-dependent increases in depth after 30 minutes. Ink penetration increases by 0.06 mm per 1 mm increase in needle length. CONCLUSION: Ink applied before MP results in the deepest penetration of ink. Microneedling offers unique advantages in transdermal delivery as its channels exhibit increasing penetration over time and lateral extension of product.