Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread globally, leading to the coronavirus disease 2019 (COVID-19) pandemic. Because a significant proportion of the COVID-19 confirmed cases were concentrated in the capital metropolitan area of South Korea, and a large proportion of the population in the area had been adequately vaccinated against COVID-19, we conducted a seroprevalence surveillance study focusing on the residents of the capital metropolitan area in South Korea. Methods: We used a quota-sampling method to obtain blood samples from 1,000 individuals per round, equally stratified across seven age categories and sexes and regions, from five medical institutions located within the capital metropolitan area of South Korea. During five consecutive months (rounds) between January 2022 and May 2022, a total of 5,000 samples were analyzed for anti-spike (S) and anti-nucleocapsid (N) antibodies. Results: High anti-S seropositivity was observed in all age groups, which corresponded to the vaccine coverage during the study period. Both the cumulative incidence based on polymerase chain reaction (PCR) and the estimated seroprevalence based on anti-N seropositivity increased in the fourth and fifth rounds, which corresponded to April 2022 and May 2022. Seroprevalence coincided with the cumulative incidence during the first three rounds, but exceeded from the fourth survey onwards when infection with omicron variants was increased rapidly in Korea. Conclusion Seroprevalence confirmed the number of infection cases outside of PCR testing-based surveillance. Seroepidemiological surveillance can help us understand vaccine responses and detect hidden infections, thereby providing appropriate public health guidance for achieving population-level immunity.

Background: Primary cicatricial alopecia (PCA) is a rare disease that causes irreversible destruction of hair follicles and affects the quality of life (QOL). Objective: We aimed to investigate the disease awareness, medical use behavior, QOL, and real-world diagnosis and treatment status of patients with PCA. Methods: A self-administered questionnaire was administered to patients with PCA and their dermatologists. Patients aged between 19 and 75 years who visited one of 27 dermatology departments between September 2021 and September 2022 were included. Results: In total, 274 patients were included. The male-to-female ratio was 1:1.47, with a mean age of 45.7 years. Patients with neutrophilic and mixed PCA were predominantly male and younger than those with lymphocytic PCA. Among patients with lymphocytic PCA, lichen planopilaris was the most common type, and among those with neutrophilic PCA, folliculitis decalvans was the most common type. Among the total patients, 28.8% were previously diagnosed with PCA, 47.0% were diagnosed with PCA at least 6 months after their first hospital visit, 20.0% received early treatment within 3 months of disease onset, and 54.4% received steady treatment. More than half of the patients had a moderate to severe impairment in QOL. Topical/intralesional steroid injections were the most common treatment. Systemic immunosuppressants were frequently prescribed to patients with lymphocytic PCA, and antibiotics were mostly prescribed to patients with neutrophilic PCA. Conclusion This study provides information on the disease awareness, medical use behavior, QOL, diagnosis, and treatment status of Korean patients with PCA. This can help dermatologists educate patients with PCA to understand the necessity for early diagnosis and steady treatment.

Background: Eosinophilic cellulitis, also known as Wells’ syndrome, is an uncommon skin disease characterized by recurrent pruritic polymorphous plaques or nodules. There is limited knowledge in the Korean literature regarding the clinical characteristics and course of eosinophilic cellulitis. Objective: To investigate the clinical and histological features of eosinophilic cellulitis in Korean patients. Methods: In this case series study, we retrospectively reviewed the electronic medical records of patients diagnosed with eosinophilic cellulitis at our institutions from 2004 to 2022. We also analyzed the literature published in dermatology and internal medicine journals in Korea. Results: A total of 17 patients were included in this study (age, 39.4±21.8 years; 12 male [70.6%]), with an average disease duration of 4.4 months. We identified six clinical variants, with the typical plaque type being the most common (33.3%), followed by the papulonodular type (22.2%). Eosinophilia was observed in 78.6% of patients, and a flame figure, which is a typical histopathological feature of eosinophilic cellulitis, was observed in 52.9% of patients. Systemic and topical steroids and antihistamines were used as first-line treatment with generally favorable results (82.4%), followed by antibiotics (35.3%), cyclosporine (23.5%), and topical calcineurin inhibitors (23.5%).The recurrence rate during the mean follow-up period of 21.8 months was 29.4%. Conclusion Eosinophilic cellulitis can present with various clinical manifestations, and flame figures do not appear in all cases; therefore, clinical and histological correlations are critical for accurate diagnosis of patients with eosinophilic cellulitis.

Pilar leiomyoma or piloleiomyoma is a benign neoplasm of the smooth muscle arising from the arrector pili muscle. It manifests as brown to red firm papulonodules with sites of predilection being the face, trunk, and extensor surfaces of the extremities. Histologically, the lesions exhibit ill-defined dermal tumors with interlacing fascicles of spindle cells. Some genodermatoses are characterized by the development of visceral tumors and cutaneous leiomyomatosis such as Reed’s syndrome, and hereditary leiomyomatosis and renal cell cancer (HLRCC). A 55-year-old male presented with reddish-brown papules and nodules on the face and upper back, accompanied by sharp episodic pain on the face. He had undergone nephrectomy for renal cancer 9 years ago, and his younger brother had similar cutaneous manifestation. Histopathologic findings were consistent with pilar leiomyoma, showing bundles of smooth muscle tumors in the dermis. Based on the clinical information including clinical features, past medical history, and family history, HLRCC was highly suspected.To confirm the diagnosis, whole exome sequencing was performed using peripheral blood, which revealed a novel point mutation (c.739G>A, p.Glu247Lys) in the fumarate hydratase (FH) gene. We describe a confirmed case of HLRCC, which is a genetic disorder with a potential to cause visceral cancers, which dermatologists might overlook as a benign condition.

Nevus sebaceus is a hamartomatous lesion characterized by epidermal, follicular, sebaceus, and apocrine gland abnormalities. Approximately 25% of affected individuals may develop benign or malignant secondary neoplasms within the preceding nevus sebaceus. Primary cutaneous apocrine carcinoma (PCAC) is a rare malignant skin tumor affecting elderly adults in their sixth decade of life. Histologically, PCAC appears as a dermal tumor displaying apocrine differentiation with decapitation secretion and malignant features. Secondary malignancy arising from nevus sebaceus is a rare complication, especially for apocrine carcinoma. To date, approximately 200 cases of PCAC have been reported in the literature, and only a few cases have developed PCAC on the scalp. Very few cases (approximately only 12) of PCACs developing in nevus sebaceus have been reported. Here, we report an extremely rare case of the coexistence of PCAC and syringocystadenoma papilliferum arising within nevus sebaceus of the scalp.

Background: Pediatric alopecia areata (AA) can affect the quality of life (QoL) of patients and their family members. Research on the QoL and burden on family members in pediatric AA is limited. Objective: This nationwide multicenter questionnaire study described the QoL and burden of the family members of patients with pediatric AA. Methods: This nationwide multicenter questionnaire study enrolled AA patients between the ages of 5 and 18 years from March 1, 2017 to February 28, 2018. Enrolled patients and their parents completed the modified Children’s Dermatology Life Quality Index (CDLQI) and the modified Dermatitis Family Impact (mDFI). The disease severity was measured using the Severity of Alopecia Tool (SALT) survey scores. Results: A total of 268 patients with AA from 22 hospitals participated in this study. Our study found that the efficacy and satisfaction of previous treatments of AA decreased as the severity of the disease increased. The use of home-based therapies and traditional medicines increased with the increasing severity of the disease, but the efficacy felt by patients was limited. CDLQI and mDFI scores were higher in patients with extensive AA than those with mild to moderate AA. The economic and time burden of the family members also increased as the severity of the disease increased. Conclusion The severity of the AA is indirectly proportional to the QoL of patients and their family members and directly proportional to the burden. Physicians need to understand these characteristics of pediatric AA and provide appropriate intervention to patients and their family members.

Background: This study aimed to investigate whether respiratory syncytial virus (RSV) and influenza virus (IFV) infections would occur in 2021–2022 as domestic nonpharmaceutical interventions (NPIs) are easing. Methods: Data were collected from the Korean Influenza and Respiratory Virus Monitoring System database. The weekly positivity rates of respiratory viruses and number of hospitalizations for acute respiratory infections were evaluated (January 2016–2022).The period from February 2020 to January 2022 was considered the NPI period. The autoregressive integrated moving average model and Poisson analysis were used for data analysis. Data from 14 countries/regions that reported positivity rates of RSV and IFV were also investigated. Results: Compared with the pre-NPI period, the positivity and hospitalization rates for IFV infection during 2021–2022 significantly decreased to 0.0% and 1.0%, respectively, at 0.0% and 1.2% of the predicted values, respectively. The RSV infection positivity rate in 2021–2022 was 1.8-fold higher than that in the pre-NPI period at 1.5-fold the predicted value. The hospitalization rate for RSV was 20.0% of that in the pre-NPI period at 17.6% of the predicted value. The re-emergence of RSV and IFV infections during 2020–2021 was observed in 13 and 4 countries, respectively. Conclusion During 2021–2022, endemic transmission of the RSV, but not IFV, was observed in Korea.

Background: The preventable trauma death rate survey is a basic tool for the quality management of trauma treatment because it is a method that can intuitively evaluate the level of national trauma treatment. We conducted this study as a national biennial follow-up survey project and report the results of the review of the 2019 trauma death data in Korea. Methods: From January 1, 2019 to December 31, 2019, of a total of 8,482 trauma deaths throughout the country, 1,692 were sampled from 279 emergency medical institutions in Korea. All cases were evaluated for preventability of death and opportunities for improvement using a multidisciplinary panel review approach. Results: The preventable trauma death rate was estimated to be 15.7%. Of these, 3.1% were judged definitive preventable deaths, and 12.7% were potentially preventable deaths. The odds ratio for preventable traumatic death was 2.56 times higher in transferred patients compared to that of patients who visited the final hospital directly. The group that died 1 hour after the accident had a statistically significantly higher probability of preventable death than that of the group that died within 1 hour after the accident. Conclusion The preventable trauma death rate for trauma deaths in 2019 was 15.7%, which was 4.2%p lower than that in 2017. To improve the quality of trauma treatment, the transfer of severe trauma patients to trauma centers should be more focused.

Background: Melasma shows characteristic histological features of photoaged skin. Objective: We evaluated the effect of dermal rejuvenation using a temperature-controlled continuous non-invasive radiofrequency (RF) device on melasma. Methods: Continuous skin heating at the temperature of 43°C for 20 minutes was performed in ten subjects with melasma who underwent 3 tri-weekly RF sessions. Pigmentation was evaluated with Mexameter® and investigator’s global assessment (IGA). Immunohistochemical staining and image analysis was performed to evaluate biopsies from melasma skin before and after the treatment. Results: The lesional melanin index was decreased by 13.7% at week 9. IGA score was improved from 3.50 at baseline to 2.95 at week 9. No significant adverse event was reported. Histologic analysis revealed reduced melanin and increased collagen density and thickness.The expression of procollagen-1 and type IV collagen was increased after the treatment. The number of p16 INK4A -positive senescent fibroblasts was reduced after the treatment, while the expression of heat shock protein 70 and 90 was increased. Stromal derived factor-1, a senescence-associated anti-melanogenic factor secreted from the fibroblasts, was up-regulated after the treatment, while the level of c-kit was not changed. Conclusion Thermal skin stimulation by the temperature-controlled continuous RF device improved melasma through dermal rejuvenation.