(1) Background: A growing body of evidence highlights that intestinal dysbiosis is associated with the development of psoriasis. The gut–skin axis is the novel concept of the interaction between skin diseases and microbiome through inflammatory mediators, metabolites and the intestinal barrier. The objective of this study was to synthesize current data on the gut microbial composition in psoriasis. (2) Methods: We conducted a systematic review of studies investigating intestinal microbiome in psoriasis, using the PRISMA checklist. We searched MEDLINE, EMBASE, and Web of Science databases for relevant published articles (2000–2020). (3) Results: All of the 10 retrieved studies reported alterations in the gut microbiome in patients with psoriasis. Eight studies assessed alpha- and beta-diversity. Four of them reported a lack of change in alpha-diversity, but all confirmed significant changes in beta-diversity. At the phylum-level, at least two or more studies reported a lower relative abundance of Bacteroidetes, and higher Firmicutes in psoriasis patients versus healthy controls. (4) Conclusions: There is a significant association between alterations in gut microbial composition and psoriasis; however, there is high heterogeneity between studies. More unified methodological standards in large-scale studies are needed to understand microbiota’s contribution to psoriasis pathogenesis and its modulation as a potential therapeutic strategy.

Introduction An increased incidence of tinea capitis has been observed over the last few decades. Trichoscopy is a non-invasive, in-office method helpful in establishing the correct diagnosis in patients with hair loss and inflammatory hair disorders. The objective was to review and analyze current data on the trichoscopy of tinea capitis. Methods A systematic review of the literature was conducted using the PubMed, EBSCO and Scopus databases. The search terms included ‘tinea capitis’ combined with ‘trichoscopy’, ‘dermatoscopy’, ‘dermoscopy’, ‘videodermatoscopy’ or ‘videodermoscopy’. Results Of 326 articles, 37 were considered eligible for the quantitative analysis. The most characteristic (with a high predictive value) trichoscopic findings of tinea capitis included comma hairs (51%), corkscrew hairs (32%), Morse code-like hairs (22%), zigzag hairs (21%), bent hairs (27%), block hairs (10%) and i-hairs (10%). Other common, but not characteristic, trichoscopic features were broken hairs (57%), black dots (34%), perifollicular scaling (59%) and diffuse scaling (89%). Morse code-like hairs, zigzag hairs, bent hairs and diffuse scaling were only observed in Microsporum tinea capitis (8/29, 28%; 6/29, 21%; 4/29, 14% and 4/29, 14%, respectively). In Trichophyton tinea capitis, corkscrew hairs were more commonly detected compared to Microsporum tinea capitis (21/38, 55% vs 3/29, 10%). Conclusion The presence of characteristic trichoscopic features of tinea capitis is sufficient to establish the initial diagnosis and introduce treatment before culture results are available. Trichoscopy may be useful in distinguishing between Microsporum and Trichophyton tinea capitis.

Alopecia areata is a type of non-scarring hair loss. The dysregulation of numerous systemic Th1 (IL-2, IFN-γ, TNF, IL-12, and IL-18), Th2 (IL-4, IL-5, IL-6, IL-9, IL-10, IL-13, IL-17E, IL-31 and IL-33) and Th17 (IL-17, IL-17F, IL-21, IL-22, IL-23 and TGF-β) cytokines was observed in patients with alopecia areata. Positive correlations between the severity of alopecia areata and an increased serum level of various cytokines including IL-2, TNF, IL-12, IL-17, and IL-17E were reported in the literature. An increased serum level of numerous cytokines, such as IL-2, IL-6, TNF, IL-12, IL-17E, and IL-22, was described as positively correlated with the duration of the disease. Moreover, it was shown that increased pre-treatment serum level of IL-12 was a positive, while increased serum levels of IL-4 and IL-13 were negative prognostic markers for the efficacy of diphenylcyclopropenone. In conclusion, alopecia areata is associated with the dysregulation of systemic Th1, Th2 and Th17 cytokines with their role in the pathogenesis, clinical manifestations and prognosis of the disease. Available data indicate the most significant role of serum IL-2, TNF, IL-12, IL-17, and IL-17E as markers of disease activity. The serum levels IL-4, IL-12 and IL-13 may be useful as potential predictors of diphenylcyclopropenone efficacy.