Background The morphology of hair regrowth in alopecia areata (AA) patches could be classified into four types, namely diffuse, irregular, marginal, and targetoid patterns, according to the DIMT classification. However, factors affecting hair regrowth patterns have not been investigated. Objective We investigated whether the DIMT-classified hair regrowth patterns of AA patches are associated with treatment modality and patch size. Methods We conducted a retrospective, cross-sectional study of 152 AA patches with hair regrowth. Results The associations between the diffuse pattern and patch size >2 cm ( p =0.006; odds ratio [OR]: 0.36, 95% confidence interval [CI]: 0.17~0.74), between the irregular pattern and triamcinolone acetonide intralesional injection ( p <0.001; OR: 274.87, 95% CI: 25.75~2,933.56), between the marginal pattern and systemic and topical corticosteroid ( p =0.018; OR: 4.89, 95% CI: 1.31~18.27), and between the targetoid pattern and patch size >2 cm ( p =0.028; OR: 2.50, 95% CI: 1.10~5.68) were statistically significant. Conclusion Treatment modalities and patch size are the factors affecting hair regrowth patterns in AA patches.

Whether having a tattoo increases the risk of transfusion-transmitted diseases (TTDs) is controversial. Although a few studies have suggested a strong association between having tattoos and TTDs, other studies have not shown the significance of the association. In addition, previous studies mainly focused only on hepatitis C viral infections. The objective of our study was to identify the prevalence and risk of TTDs in people with tattoos as compared with the non-tattooed population. A systematic review of the studies published before January 22, 2021, was performed using the Pubmed, Embase, and Web of Science databases. Observational studies on hepatitis C virus (HCV), hepatitis B virus (HBV), human immunodeficiency virus (HIV), and syphilis infections in people with and without tattoos were included. Studies that reported disease status without serological confirmation were excluded. A total of 121 studies were quantitatively analyzed. HCV (odds ratio [OR], 2.37; 95% confidence interval [CI], 2.04–2.76), HBV (OR, 1.55; 95% CI, 1.31–1.83), and HIV infections (OR, 3.55; 95% CI, 2.34–5.39) were more prevalent in the tattooed population. In subgroup analyses, the prevalence of HCV infection was significantly elevated in the general population, hospital patient, blood donor, intravenous (IV) drug user, and prisoner groups. IV drug users and prisoners showed high prevalence rates of HBV infection. The prevalence of HIV infection was significantly increased in the general population and prisoner groups. Having a tattoo is associated with an increased prevalence of TTDs. Our approach clarifies in-depth and supports a guideline for TTD screening in the tattooed population.

Background Reduced lipid content in the stratum corneum is a major cause of skin-barrier dysfunction in various pathological conditions. Promoting lipid production is a potential strategy to improve skin-barrier function. Recent evidence supports the beneficial effects of adiponectin on lipid metabolism and senescence in keratinocytes. Objective This study aimed to investigate whether plant extracts can enhance skin-barrier function. Methods We screened fruit and herb extracts that enhance the lipid synthesis of keratinocytes via AMP-activated protein kinase (AMPK) activation and SIRT1 signaling in the adiponectin pathway. The levels of major lipid synthesis enzymes and transcription factors as well as epidermal barrier lipids involved in adiponectin-associated epidermal barrier formation were evaluated in the herbal extracts- or adiponectin-treated human epidermal keratinocyte and equivalent models. The mRNA expression of major lipid synthesis enzymes increased following treatment with Lycii Fructus , Prunus tomentosa , and Melia toosendan extracts. Results The expression of transcription factors SIRT1, liver X receptor α, peroxisome proliferator-activated receptors (PPARs), and sterol regulatory element-binding proteins (SREBPs) were upregulated. Levels of free fatty acids, cholesterol, and ceramides were elevated. The expression of keratinocyte differentiation markers increased. In particular, among fruit extracts with a detectable effect, Melia toosendan induced the highest expression of lipid synthase. Conclusion These results indicate that Melia toosendan is a promising candidate for improving skin-barrier function.

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Dear Editor, Recent studies have suggested an association between the type 2 diabetes mellitus (T2DM) drugs dipeptidyl peptidase-4 inhibitors (DPP4i) and bullous pemphigoid (BP). [1][2][3] The risk ratio for developing BP in patients taking DPP4i ranges from 2.21 to 3.60 in Western studies. 2 However, large-scale studies investigating this relationship are limited in Asia. Thus, herein, we investigated the risk of DPP4i use in BP development using nationwide population-based data in Korea.This study used data from the National Health Insurance Service database of Korea (NHIS) from 2011 to 2018 (Research Data No: REQ0000040384). The NHIS is operated by the Korean government and contains the data of 98% of the Korean population. 4 Patients newly diagnosed with T2DM, according to the International Statistical Classification of Disease, 10th Revision (ICD-10 codes: E11, E13, or E14), from 2011 to 2015 were enrolled. Those marked with the 'L120' code (bullous pemphigoid) after a T2DM diagnosis were defined as BP patients. According to prescription frequency in Korea, DPP4i was classified into four categories: sitagliptin, vildagliptin, linagliptin and other gliptins. Follow-up was initiated from the date of T2DM diagnosis in the DPP4i non-exposed group and from the first date of prescription in the DPP4i-exposed group. Cox hazard regression was performed for the total population and subgroups divided by age ('≥40s', '≥50s', '≥60s', '≥70s' and '≥80s'). Moreover, the risk ratio for each type of DPP4i used to develop BP was evaluated. All statistical analyses were performed using SAS version 9.4 and R version 3.6.3.Among the 1,197,225 patients, 485,709 (40.57%) received DPP4i, of whom 170 (0.01%) developed BP. There was a slight female predominance in BP patients (female:male, 1.15:1) (Table 1). In the total cohort, the risk of DPP4i for BP incidence was not significant (aHR, 1.103; 95% CI, 0.917-1.328; Figure 1a). However, it was significant in those aged ≥50 years and gradually increased in the older subgroups (Figure 1c-f). Each type of DPP4i showed similar trends, except for sitagliptin, which showed no significant difference in any group (Figure 1g-i).This study found that DPP4i administration is associated with an increased risk of developing BP in those aged ≥50 years, and the risk increases with age. Linagliptin and vildagliptin were highly associated with the development of BP, which is consistent with previous studies. 5,6 However, sitagliptin did not show a significant risk of developing BP, in contrast to the results of previous studies. 5 Nevertheless, even those studies reported that vildagliptin and linagliptin were more strongly associated with BP development than sitagliptin. 5,6 Moreover, differences in BP severity caused by each DPP4i type have recently been reported. 7 Therefore, prescribing sitagliptin