Comma and corkscrew hairs are trichoscopic markers of tinea capitis. Although comma hairs have been reported in both black and white patients with tinea capitis, corkscrew hairs were previously hypothesized to manifest exclusively in patients with curly or African hair types. However, we report a significant number of comma and corkscrew hairs in a Hispanic female patient with naturally straight hair and Trichophyton tonsurans tinea capitis. Thus, dermoscopy is a rapid, noninvasive, and cost-effective tool for evaluating tinea capitis and should be used in combination with culture in all patients regardless of hair texture or race.

Importance

Although cutaneous warts are common lesions, full remission is not always achieved with conventional therapies. Laser modalities including carbon dioxide (CO2), erbium:yttrium-aluminum-garnet (Er:YAG), pulsed dye (PDL), and Nd:YAG have been investigated as alternative treatments for warts.

Objective

To review the use and efficacy of lasers for treating nongenital cutaneous warts.

Evidence review

Published randomized clinical trials (RCTs), cohort studies, case series, and case reports involving laser treatment of nongenital warts were retrieved by searching PubMed with no date limits. Quality ratings of studies were based on a modified version of the Oxford Centre for Evidence-Based Medicine scheme for rating individual studies. A higher emphasis was placed on RCTs and prospective cohort studies with large sample sizes and detailed methodology.

Findings

There were 35 studies published between 1989 and 2015 that comprised an aggregate of 2149 patients. Simple and recalcitrant nongenital warts treated with lasers show variable response rates (CO2 laser, 50%-100%; Er:YAG laser, 72%-100%; PDL, 47%-100%; and Nd:YAG laser, 46%-100%). Current RCTs suggest that PDL is equivalent to conventional therapies such as cryotherapy and cantharidin. Combination therapies with lasers and other agents including bleomycin, salicylic acid, and light-emitting diode have shown some success.

Conclusions and relevance

Lasers can be an effective treatment option for both simple and recalcitrant warts. The lasers most studied for this purpose are CO2, PDL, and Nd:YAG, and of these, PDL has the fewest adverse effects. Currently, use of lasers for wart treatment is limited by lack of established treatment guidelines. Future studies are needed to compare laser modalities with each other and with nonlaser treatment options, and to establish optimal treatment protocols.

Endogenous sphingolipids (ceramide) and related synthetic molecules (FTY720, SH-BC-893) reduce nutrient access by decreasing cell surface expression of a subset of nutrient transporter proteins. Here, we report that these sphingolipids disrupt endocytic recycling by inactivating the small GTPase ARF6. Consistent with reported roles for ARF6 in maintaining the tubular recycling endosome, MICAL-L1-positive tubules were lost from sphingolipid-treated cells. We propose that ARF6 inactivation may occur downstream of PP2A activation since: (1) sphingolipids that fail to activate PP2A did not reduce ARF6-GTP levels; (2) a structurally unrelated PP2A activator disrupted tubular recycling endosome morphology and transporter localization; and (3) overexpression of a phosphomimetic mutant of the ARF6 GEF GRP1 prevented nutrient transporter loss. ARF6 inhibition alone was not toxic; however, the ARF6 inhibitors SecinH3 and NAV2729 dramatically enhanced the killing of cancer cells by SH-BC-893 without increasing toxicity to peripheral blood mononuclear cells, suggesting that ARF6 inactivation contributes to the anti-neoplastic actions of sphingolipids. Taken together, these studies provide mechanistic insight into how ceramide and sphingolipid-like molecules limit nutrient access and suppress tumor cell growth and survival.