UV-A radiation is associated with accelerated skin aging, while UV-B exposure is associated with sunburns. 1 Exposure to both types of radiation is a major risk factor for the development of skin cancer. 1 By protecting the skin from UV light, sunscreen protects against these negative sequelae of sun exposure. 2-4 In 2011, the US Food and Drug Administration announced new regulations for sunscreen labels to emphasize the importance of protection against both UV-A and UV-B radiation, now known as broad-spectrum protection. 5,6 In this survey study, we assessed consumer comprehension of sunscreen labels and knowledge of general sun protective behaviors.

IMPORTANCE Subungual melanoma in situ (SMIS) is a malignant neoplasm that requires early diagnosis and complete surgical excision; however, little is known about the usefulness of the detailed dermoscopic features of longitudinal melanonychia (LM) to predict the diagnosis of SMIS. OBJECTIVES To investigate the characteristic dermoscopic findings of SMIS and to establish a predictive scoring model for the diagnosis of SMIS in patients with adult-onset LM affecting a single digit.

Background/Aims: This study examined the role of random normal skin biopsy in the diagnosis of intravascular lymphoma (IVL) in adult Western patients with clinically diagnosed hemophagocytic lymphohistiocytosis (HLH). Methods: In a retrospective chart review study, we analyzed a total of 59 skin biopsies that were performed to diagnose IVL in 21 adult patients with HLH seen at Stanford Hospital between 2004 and 2016. Results: Out of the 59 skin biopsies, 42 were taken from clinically normal-appearing skin and 17 from clinically abnormal-appearing skin. None of the 59 biopsies revealed a diagnosis of primary or metastatic malignancy, regardless of the malignancy history, clinical presentation, and biopsy and histopathologic characteristics. A review of 8 positive IVL cases at Stanford Hospital including 1 case associated with HLH showed 1 positive diagnosis by a targeted skin biopsy and other positive diagnoses by bone marrow (n = 4), lung (n = 2), brain (n = 2), muscle (n = 1), and nerve (n = 1). Conclusion: Random skin biopsies have a limited role in diagnosing IVL in adult patients with HLH, in the setting of a single academic institution in the USA. A review of the literature emphasizes the role of a full body skin exam with a selective skin biopsy in these patients.

rythropoietic protoporphyria (EPP) is an inherited disease of heme biosynthesis resulting from a mutation in the ferrochelatase gene, leading to the accumulation of protoporphyrin. Erythropoietic protoporphyria manifests in early childhood as burning pain, edema, bullae, and erosions in response to sun exposure. 1 There have been reports that treatment with cimetidine, a histamine H 2 -receptor antagonist that inhibits δ-aminolevulinic acid synthase, results in symptomatic improvement in patients with acute intermittent porphyria (AIP) and porphyria cutanea tarda (PCT). 2-7 A single case report 8 also describes the use of cimetidine for the effective treatment of an adult patient with EPP. Herein we report the first case series, to our knowl-edge, describing the safe and effective use of cimetidine in 3 pediatric patients with EPP.

Activation of insulin-like growth factor-1 (IGF-1) receptor (IGF1R) signaling induces keratinocyte migration, but little is known about its regulation, including in diabetic wounds. GM3, a lipid raft ganglioside synthesized by GM3 synthase (GM3S), regulates receptor signaling. In diabetic mice, knockout or topically applied nanoconstruct-mediated knockdown of GM3S promotes wound edge IGF1R phosphorylation and re-epithelialization. Through modulating GM3 expression, we explored the role of GM3 in regulating human keratinocyte IGF1R signaling. Increases in GM3 and GM3S expression, including by exposure to high glucose, inhibit keratinocyte migration and IGF-1–induced chemotaxis in association with inhibition of IGF1R phosphorylation, suppression of Rac1 signaling, and activation of RhoA signaling. In contrast, GM3 depletion accelerates cell migration; increases cell velocity, displacement, and persistence; and activates IGF1R-Rac1 signaling. These data implicate GM3 in mediating glucose-induced suppression of IGF1R-Rac1 signaling. Furthermore, our findings provide evidence of a pivotal role for GM3-induced insulin resistance in impairing keratinocyte migration and reinforce the previously published studies in diabetic mice supporting GM3-depleting strategies as an approach for accelerating the healing of human diabetic wounds.