Background: Psoriasis is a persistent systemic inflammatory condition mediated by the interleukin (IL)-23/IL-17 signaling pathway. Existing murine models, including imiquimod (IMQ)-applied wild-type (WT) mice, may not reflect chronicity and systemic comorbidities of psoriasis, particularly gut-related manifestations linked to the gut–skin axis. Objective: To establish a murine model that more accurately reflects chronic psoriasis, its systemic comorbidities, and associated gut environment alterations. Methods: C57BL/6 IL-10-deficient (IL-10 knockout [KO]) and WT mice received topical IMQ or vehicle for 6 weeks. Subsequently, tissue samples from skin, colon, joints, kidneys, liver, abdominal aortas, lymph nodes, and spleens, as well as fecal and blood samples, were collected for histopathologic, immunologic, gut environment analysis. Results: IMQ-treated IL-10 KO mice developed prolonged psoriatic inflammatory responses with increased epidermal thickness and higher infiltration of CD45+, myeloperoxidase+, and IL-17+ cells. They also exhibited early-onset, severe colitis with marked weight loss, shortened colon length, and elevated colitis severity scores. While IMQ induced systemic inflammation in multiple organs, IL-10 KO mice did not show more severe joint, liver, or kidney involvement than WT mice. Elevated serum tumor necrosis factor alpha and plasminogen activator inhibitor-1 levels, increased heart/body weight ratio, enhanced gut permeability, and distinct gut microbiota profiles were observed in IL-10 KO mice. Conclusion The 6-week IMQ-applied IL-10 KO model may better reflect chronic and severe psoriasis with gut-related comorbidities, offering a valuable platform to investigate the gut–skin axis.

Background: Observational studies have suggested associations between dietary polyunsaturated fatty acids (PUFAs) and cancer risk; however, causal inference regarding skin cancer remains limited due to potential recall bias, confounding, and reverse causation. Objective: This study aimed to evaluate the causal association between genetically predicted circulating PUFA levels and the risk of skin cancers, including basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and melanoma. Methods: We conducted a 2-sample Mendelian randomization (MR) study using genome-wide association study summary statistics from the UK Biobank (PUFAs, n=115,006) and the FinnGen consortium (BCC, n=26,272; SCC, n=4,663; melanoma, n=5,753). Genetic instruments were derived for omega-3, docosahexaenoic acid, omega-6, linoleic acid, and the omega-6:3 ratio.Multiple MR methods—including inverse-variance weighted, MR-Egger, weighted median, weighted mode, and MR-PRESSO—were applied to test for consistency and assess pleiotropy and heterogeneity. Results: A higher genetically predicted linoleic acid to total fatty acid ratio was associated with a significantly lower risk of BCC and SCC. Conversely, higher genetically proxied serum omega-3 levels were associated with increased risks of BCC, SCC, and melanoma. The risk effect on SCC was attenuated upon exclusion of rs174528, a variant in the fatty acid desaturase 1 (FADS1) gene, suggesting a role for endogenous PUFA metabolism in carcinogenesis. Conclusion This MR analysis supports a causal role of circulating PUFAs in skin cancer development and highlights the importance of FADS-mediated endogenous PUFA metabolism. These findings provide novel insights into the genetic and metabolic underpinnings of skin cancer susceptibility.

Objective: This study examined the mediating effect of negative changes in daily life due to the coronavirus disease-2019 (COVID-19) pandemic on depressive symptoms, considering COVID-19 infection and related social concerns. Additionally, comparisons of path coefficients between the groups were conducted based on age and gender. Methods: A cross-sectional study design used data from the 2020 Korean Community Health Survey consisting of 229,269 individuals. This study used a self-reported questionnaire, including the Patient Health Questionnaire-9 and three items addressing social concerns related to COVID-19 infection. A single question assessed whether individuals had experienced COVID-19 infection within the last 3 months, and scores of negative changes in daily life due to the COVID-19 pandemic. Correlation analysis was performed on the variables. Structural equation model analysis was conducted to identify the mediating role of negative changes in daily life. Chi-square tests were also performed to compare the path coefficients based on age and gender. Results: The structural equation models revealed that COVID-19 infection and related social concerns had both significant direct effects on depressive symptoms and indirect effects through negative changes in daily life. When comparing the path coefficients by age and gender, the coefficients related to depressive symptoms were highest in those under 65 years and in females. Conclusion Negative changes in daily life due to the COVID-19 pandemic serve as a partial mediator of the impact of COVID-19 infection and related social concerns on depressive symptoms. Special attention should be paid to depressive symptoms in those under 65 years of age and in females.

Background: A set of criteria for severity classification is essential in alopecia areata (AA). Currently, no guidelines are universally accepted for defining AA severity. Objective: This study aimed to establish a set of consensus criteria for classifying the severity of and identifying treatment refractoriness in AA. Methods: A preliminary draft of the definition for moderate-to-severe AA was crafted based on available evidence, and members of the Korean Hair Research Society (KHRS) subsequently endorsed the recommendation through an online survey. Results: In the first Delphi round, consensus was attained on 15 questions. After refining certain items in the second round, consensus was achieved on 23 out of 26 questions. The KHRS first defined AA severity using the severity of alopecia tool (SALT). SALT ≥50 was defined as severe, 20≤ SALT <50 as moderate, and SALT <20 as mild. Moderate AA was considered severe if it meets one or more of the following criteria: dermatology life quality index >10, presence of accompanying eyebrow or eyelash loss, positive hair loss activity, or treatment-refractory AA. Conclusion These consensus criteria can help clinicians accurately diagnose AA, provide appropriate treatment, and monitor its progression.

Background: Alopecia areata (AA) is characterized by hair loss on the scalp and body, significantly impacting patients’ quality of life based on its severity. Objective: This study aims to identify crucial factors influencing the perception of severe AA from the patients’ viewpoint. Methods: A web-based survey was conducted among AA patients attending dermatology departments at 21 university hospitals in Korea. The survey comprised 17 criteria, exploring both clinical characteristics of AA patients and subjective determinants of disease severity. Results: A total of 791 AA patients and their caregivers participated in the survey. Approximately 30% of respondents developed AA during childhood, with 43.5% experiencing chronic courses lasting over 3 years. Half of the participants exhibited more than 20% scalp hair loss, and 42% reported additional hair loss on other body parts, such as eyelashes and nose hair.Most respondents agreed that patients with ≥20% scalp hair loss should be categorized as having severe AA. They also identified longer disease duration, involvement of non-scalp body hair, treatment refractoriness, and social or mental impairment requiring medical intervention as factors indicating increased disease severity. Conclusion This survey underscores the significant impact of AA on patients’ quality of life and highlights existing unmet needs in current treatment modalities.

Background: Pediatric trigger digit (TD) does not appear at birth but is diagnosed after birth by finding a flexion contracture of the thumb or other fingers. The reported incidence of pediatric TDs varies from 0.5 to 5 cases per 1,000 live births without sex-specific predominance. We performed a nationwide large-scale study to determine the prevalence and incidence of pediatric TDs and analyzed operative treatment for pediatric TDs using the National Health Insurance data of South Korea. Methods: Patients with pediatric TDs, aged 0–10 years between 2011 and 2020, were included in this study. Children born between 2011 and 2015 were set as the reference population and followed up until 2020. We calculated the prevalence and incidence rates of pediatric TDs according to age and sex and analyzed the operation rate, age at surgery, time interval from initial diagnosis to surgery, and follow-up period. Patient selection and treatment were based on International Classification of Diseases, 10th Revision (ICD-10). Results: The prevalence rates of pediatric TDs ranged from 0.063% to 0.084%. Girls had a higher prevalence rate (0.066%–0.094%) than boys (0.060%–0.075%). The total incidence rate was 77.6/100,000 person-years, and the incidence rate was higher in girls (84.8) than in boys (70.7). Among 2,181,814 children born between 2011 and 2015, 12,729 were diagnosed with pediatric TDs, of which 1,128 (8.9%) underwent operative management. The means of age at initial diagnosis, age at surgery, and the time interval between diagnosis and operation were 2.76 ± 1.91 years, 3.79 ± 2.19 years, and 1.15 ± 1.71 years, respectively. Conclusions High prevalence and incidence rates of pediatric TDs were found in 2- to 3-year-old patients. Among pediatric patients, 8.9% underwent operative management that was most frequently conducted between 2 and 3 years of age (within 1 year of initial diagnosis).

Background: Healthcare workers (HCWs) face an increased risk of airborne infections owing to close patient contact and extended shifts. N95 respirators require routine fit testing to ensure effective protection. This study assessed the fit stability of N95 masks among nurses working in airborne infection units, using annual fit tests to observe changes over time. Methods: From May 2020 to January 2023, 37 nurses from the high-risk airborne infection units of a university hospital participated in this study. The fit tests followed the Occupational Safety and Health Administration’s Quantitative Fit Testing protocol, and non-parametric statistical analyses were applied. Nurses received formal annual training on N95 mask use and individualized guidance before each fit test. Results: In the initial test, 46.0% passed; of these, 15 consistently passed the second test (Group 1, Pass-Pass) and 2 failed (Group 2, Pass-Fail). No significant associations were found between demographic or job factors and the fit test outcomes. Average fit scores decreased from 100.79 (±58.22) initially to 32.25 (±66.54) in the second test, showing variability. Conclusion Ongoing training and experience improved fit consistency over time, emphasizing the importance of regular education. Rather than testing annually, targeted testing when selecting a new respirator or performing subsequent facial changes may enhance the protection of HCWs and reduce costs.

Objective: This study examined the mediating effect of negative changes in daily life due to the coronavirus disease-2019 (COVID-19) pandemic on depressive symptoms, considering COVID-19 infection and related social concerns. Additionally, comparisons of path coefficients between the groups were conducted based on age and gender. Methods: A cross-sectional study design used data from the 2020 Korean Community Health Survey consisting of 229,269 individuals. This study used a self-reported questionnaire, including the Patient Health Questionnaire-9 and three items addressing social concerns related to COVID-19 infection. A single question assessed whether individuals had experienced COVID-19 infection within the last 3 months, and scores of negative changes in daily life due to the COVID-19 pandemic. Correlation analysis was performed on the variables. Structural equation model analysis was conducted to identify the mediating role of negative changes in daily life. Chi-square tests were also performed to compare the path coefficients based on age and gender. Results: The structural equation models revealed that COVID-19 infection and related social concerns had both significant direct effects on depressive symptoms and indirect effects through negative changes in daily life. When comparing the path coefficients by age and gender, the coefficients related to depressive symptoms were highest in those under 65 years and in females. Conclusion Negative changes in daily life due to the COVID-19 pandemic serve as a partial mediator of the impact of COVID-19 infection and related social concerns on depressive symptoms. Special attention should be paid to depressive symptoms in those under 65 years of age and in females.

Background: Healthcare workers (HCWs) face an increased risk of airborne infections owing to close patient contact and extended shifts. N95 respirators require routine fit testing to ensure effective protection. This study assessed the fit stability of N95 masks among nurses working in airborne infection units, using annual fit tests to observe changes over time. Methods: From May 2020 to January 2023, 37 nurses from the high-risk airborne infection units of a university hospital participated in this study. The fit tests followed the Occupational Safety and Health Administration’s Quantitative Fit Testing protocol, and non-parametric statistical analyses were applied. Nurses received formal annual training on N95 mask use and individualized guidance before each fit test. Results: In the initial test, 46.0% passed; of these, 15 consistently passed the second test (Group 1, Pass-Pass) and 2 failed (Group 2, Pass-Fail). No significant associations were found between demographic or job factors and the fit test outcomes. Average fit scores decreased from 100.79 (±58.22) initially to 32.25 (±66.54) in the second test, showing variability. Conclusion Ongoing training and experience improved fit consistency over time, emphasizing the importance of regular education. Rather than testing annually, targeted testing when selecting a new respirator or performing subsequent facial changes may enhance the protection of HCWs and reduce costs.