Cutaneous immunity, which is a key defence against the development of skin cancers, is suppressed by even small doses of ultraviolet (UV) radiation. Preventing this UV-induced immunosuppression may therefore reduce the incidence of skin cancer. Nicotinamide (vitamin B3) has immune-protective and cancer-preventive effects against UV radiation in mice, and we have shown previously that topical nicotinamide is immune protective in humans. Using the Mantoux model of skin immunity in healthy volunteers, we compared oral nicotinamide to placebo (both administered for 1 week) in a randomized, double-blinded, crossover design against the effects of solar-simulated ultraviolet (ssUV) radiation on delayed-type hypersensitivity to tuberculin purified protein derivative. Discrete areas of the back were irradiated with low doses of ssUV daily for three consecutive days. Immunosuppression, calculated as the difference in Mantoux-induced erythema of irradiated sites compared with unirradiated control sites, was determined in volunteers taking oral nicotinamide and placebo. Significant immunosuppression occurred in an UV dose-dependent manner in the presence of placebo. Oral nicotinamide, at doses of either 1500 or 500 mg daily, was well tolerated and significantly reduced UV immunosuppression with no immune effects in unirradiated skin. Oral nicotinamide is safe and inexpensive and looks promising as a chemopreventive supplement for reducing the immunosuppressive effects of sunlight.

Longwave UVA, which is poorly filtered by most sunscreens, was highly immune suppressive even at doses equivalent to 20 min of sun exposure. Nicotinamide, which protected against both UVB and UVA, is a promising agent for skin cancer prevention.

The classification of epidermolysis bullosa (EB) into 3 main subtypes has been based on transmission electron microscopy (TEM) that is able to directly visualize and quantify specific ultrastructural features. Immunofluorescence antigenic mapping (IFM) is a technique that determines the precise level of skin cleavage by determining binding sites for a series of antibodies. To date, no study has compared the accuracy of these two techniques in diagnosing the major types of EB. A prospective cohort of 33 patients thought to have EB on clinical grounds had TEM, IFM, and genetic testing performed. The sensitivities and specificities of TEM and IFM were calculated compared with the genetic results. Of 33 cases, 30 had a positive EB diagnosis. TEM subclassified EB into its three major forms in 24/30 cases (80%) and IFM in 29/30 cases (97%). Overall, TEM sensitivities and specificities when compared with genetic results were 71% and 81%, respectively. IFM sensitivities and specificities when compared with genetic results were 97% and 100%, respectively. If a patient tested positive for EB by IFM, the likelihood ratio of having a particular type of EB was consistently greater than 20 against the reference standard (compared with a likelihood ratio less than 10 for TEM). Our results indicate that the diagnosis of EB is improved (sometimes substantially) by the use of IFM compared with TEM.

Recommendations on dermatologic surgery during the COVID-19 pandemicTo the Editor: We read with interest the article by Chen et al 1 reporting the experience of a dermatology department at the center of the COVID-19 pandemic. As doctors, we have a responsibility to support measures that mitigate the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), but at the same time, to provide essential medical care to our patients.Cutaneous oncology poses a unique set of challenges. Having patients attend dermatologic surgery clinics increases the risk of transmission of SARS-CoV-2, takes medical staff away from other settings (including upskilling in critical care), and uses limited health care resources such as personal protective equipment. Deferring planned surgery may allow for disease progression, increasing tumor burden, which may result in more complex surgery and reconstruction, increasing the risk of metastasis, and the ultimate burden on the health care system.