Background During coronavirus disease 2019 (COVID‐19) pandemic, various adverse skin reactions to long‐term mask wearing have been reported. Objective We aimed to assess the clinical features of mask‐induced dermatoses and recommend prevention and treatment options. Methods From April to August 2020, questionnaires including preexisting skin disorders, patients’ reported mask‐related symptoms, their daily mask wearing duration and frequency, types of masks used, whether they are health care workers, and demographic information were distributed to patients of 12 hospitals. Dermatologists assessed skin lesions, confirmed diagnosis, and recorded treatment modalities. Results Itchiness was the most frequent symptom, mostly affecting the cheeks. Most common skin disease was new‐onset contact dermatitis (33.94%), followed by new‐onset acne (16.97%) and aggravation of preexisting acne (16.97%). Daily wearing ( p =0.018) was significantly associated with new‐onset contact dermatitis. More than half of the patients with preexisting skin problems experienced aggravation while wearing masks. Longer duration (more than 6 hours/day, p =0.043) and cotton masks ( p <0.001) significantly increased acne flare‐up. Healthcare workers had a higher incidence of skin disease. Skin lesions were generally mild and well tolerated with topical agents. Limitations Effect of seasonal characteristics and other risk factors were not assessed. The patients were visiting dermatologic clinics and had interest in their skin status. Thus, a selection bias may exist. Conclusion Mask‐induced/triggered dermatoses contribute to increase the dermatological burden during pandemic.

"Fiddler's neck" is an irritant contact dermatitis that frequently affects violin and viola players. The etiology of the skin changes associated with this condition are probably attributable to a combination of factors--including increased pressure, friction, poor hygiene, and excessive perspiration. Clinically, the lesions generally consist of a localized area of lichenification on the left side of the neck just below the angle of the jaw. Herein, we report a case of fiddler's neck in a viola player, attended by allergic contact dermatitis to the nickel in the metal fixtures of a viola. We hope that our case report draws the attention of dermatologists toward this, and many other skin problems that affect musicians.

Carcinoma erysipelatoides, also known as inflammatory metastatic carcinoma, is a rare form of cutaneous metastasis. It is most commonly caused by breast carcinoma, but rarely associated with gastric adenocarcinoma. Herein, we report an unusual case of carcinoma erysipelatoides in a 55 year-old female who had been diagnosed with signet ring cell carcinoma of the stomach metastasizing to ovaries.

Background/Aims: Recent studies have shown a cumulative dose-dependent association between the use of hydrochlorothiazide (HCTZ) and skin cancer, including melanoma and non-melanoma skin cancer (NMSC) in Western Europe. However, whether this pattern is present in East Asia countries is unknown. The aim of this study was to examine the association between HCTZ use and the risk of skin cancer among a cohort of hypertensive patients in South Korea. Methods: This was a retrospective, population-based cohort study using the database from the Health Insurance Review and Assessment Service between January 1, 2007 and June 30, 2017 in South Korea. We identified patients diagnosed with melanoma and NMSC in the cohorts of essential hypertensive patients who were treated with HCTZ or antihypertensive agents other than HCTZ. Using Cox proportional hazards regression models, the hazard ratios (HR) for skin cancer associated with HCTZ users were calculated. Results: The risk of melanoma was significantly lower in HCTZ-users compared with non-HCTZ users (HR, 0.85; 95% confidence interval [CI], 0.75 to 0.97; p = 0.016), and the risk of NMSC was lower in the HCTZ users but no statistically significant association was seen (HR, 0.96; 95% CI, 0.91 to 1.02; p = 0.236). High cumulative doses (≥ 50,000 mg) of HCTZ were associated with decreased risk of both NMSC (HR, 0.20; 95% CI, 0.10 to 0.38; p < 0.001) and melanoma (HR, 0.18; 95% CI, 0.04 to 0.70; p = 0.001), respectively. Conclusions: High cumulative use of HCTZ may have a chemopreventive effect against the development of melanoma and NMSC with clear cumulative dose-response and duration-response relationships in South Korea.

Quite a few patients with chronic spontaneous urticaria (CSU) are refractory to H 1 -antihistamines, even though the dose of H 1 -antihistamines is increased up to 4-fold. CSU that is not controlled with H 1 -antihistamines results in increased disease burden. Several immunomodulators have been used to manage these patients. The guidelines reported herein are connected to Part 1 of the KAAACI/KDA Evidence-Based Practice Guidelines for Chronic Spontaneous Urticaria in Korean Adults and Children, and aimed to provide evidence-based recommendations for the management of H 1 -antihistamine-refractory CSU. Part 2 focuses on the more commonly used additional treatment options for refractory CSU, including omalizumab, cyclosporine, leukotriene receptor antagonist, dapsone, methotrexate, and phototherapy. The evidence to support their efficacy, dosing, safety, and selection of these agents is systematically reviewed. To date, for patients with refractory CSU, the methodologically sound data to evaluate the use of omalizumab has been growing; however, the evidence of other immunomodulators and phototherapy is still insufficient. Therefore, an individualized stepwise approach with a goal of achieving complete symptom control and minimizing side effects can be recommended. Larger controlled studies are needed to elevate the level of evidence to select a rational therapeutic agent for patients with refractory CSU.