Background Studies have begun to investigate the complex relationship between host and microorganisms in non‐infectious pathologies such as acne, atopic dermatitis and psoriasis. Though the skin is exposed to environmental stressors such as ultraviolet radiation (UVR), no studies exist examining the effects of both UVA and UVB on the skin microbiome. Objective To test the effect of UVA and UVB on human skin microbiome. Methods To test whether UV will alter the cutaneous microbiome, participants were exposed to doses of UVA (22‐47 J/cm2) or UVB (100‐350 mJ/cm2) and samples were collected. DNA was isolated and sequenced to identify the microbial composition of each sample. Results There was vast intra‐ and inter‐subject variation at all time points, and phylum and species‐level differences were identified. These included an increase in the phylum Cyanobacteria and a decrease in the family Lactobacillaceae and Pseudomonadaceae. The sensitivity of microbes to UVR and their re‐colonization potential following exposure differed in UVA vs UVB samples. Limitations The sample size was small, and the study was limited to males. Conclusion The results demonstrate that UVR has profound qualitative and quantitative influences on the composition of the skin microbiome, possibly effecting skin pathology in which UVR is a factor.

Introduction Hidradenitis Suppurativa (HS) is a chronic inflammatory disease of the skin highly associated with firsthand smoking. Secondhand smoke, defined as the inhalation of smoke from burning a tobacco product or smoke that is exhaled by smokers, and its relationship to HS has not been assessed. This study aims to determine the prevalence of secondhand smoke exposure in the HS population. Methods In this cross-sectional study (N=136), surveys were both administered in a dermatology clinic and emailed to patients with HS, verruca vulgaris (VV), and atopic dermatitis (AD). Control groups were selected based on secondhand smoke associations: AD has a known association, whereas VV does not. Results The survey response rate was 67.3% (N=136). We found that more than half of HS patients (58.73%) were exposed to secondhand smoke within the last 12 months, whereas 38.30% and 30.77% in the AD and VV groups were exposed, respectively (p=0.0209). Additionally, our data did not identify a significant correlation between secondhand smoke and HS disease severity. Conclusion Our study is the first to assess the prevalence of secondhand smoke exposure in the HS population. However, due to the limitations of the study design and significant differences between study groups, we were unable to assess the true association between HS and secondhand smoke exposure. While our study did not identify an increased prevalence of secondhand smoke exposure in the HS population, it highlights an area for further investigation evaluating the relationship between passive tobacco exposure and inflammatory skin disease.

Background: Anti-FcεRIa and anti-IgE antibodies have recognized to be related with autoimmune chronic spontaneous urticaria (CSU). The in vivo autologous serum skin test (ASST) is widely used to detect autoreactivity in autoimmune CSU, but its meaning is controversial. Objective: To recomfirm whether the ASST correlate the titer of anti-FcεRIa and anti-IgE antibody, disease severity, and effect of cycrosprine in CSU patients. Methods: We performed ASST in 61 CSU patients. Sera from patients and saline as a negative control were injected intradermally to forarms. The wheal response was measured at 30 min after injections, and was taken to be positive when the diameter of wheal is 2 mm bigger than that with saline. Disease severity was evaluated by Urticaria Activity Score (UAS) 7. Anti-FcεRIa antibody or anti-IgE antibody was detected by ELISA. Results: Twenty five out of 61 CSU patients were positive for ASST. The levels of anti-FcεRIa antibody and improvement of UAS7 with oral cycrosporine were significantly higher in ASST positive patients compared to negative patients (P¼ 0.0294, P¼0.00179), and there was no significant diffrence in levels of anti-IgE antibody in both groups (P¼0.189). Conclusions: These findings suggest that detection of anti-FcεRIa antibody may substitute ASST to predict the efficacy of cycrosporine for CSU patients.