Impact of the COVID-19 pandemic on telogen effluvium: a nationwide multicentre interrupted time series study.

BACKGROUND: There is ongoing debate regarding the association between telogen effluvium (TE) and COVID-19, as well as COVID-19 vaccines. OBJECTIVES: To investigate the impact of the COVID-19 pandemic and vaccination on the development of TE among patients visiting dermatology clinics in South Korea. METHODS: Between 2017 and 2022, data regarding patients with TE and other types of hair loss were collected from 22 hospitals in South Korea. An interrupted time series analysis was conducted, dividing the time into periods before and after the COVID-19 pandemic, as well as before and after the COVID-19 vaccination. RESULTS: There was a significant slope change in the percentage of cases of TE during the postpandemic period (slope change 0.011, 95% confidence interval 0.005-0.017, P < 0.001), but no significant changes were observed after vaccination. The percentage of patients with other types of hair loss was not associated with COVID-19 or vaccination. The retrospective nature of the study may have limited the ability to establish causation. CONCLUSIONS: This multicentre study provides insights into the epidemiology of TE, showing a significant increase in cases of TE following the COVID-19 pandemic. However, there was no association between the occurrence of TE and COVID-19 vaccines.

Korean Consensus Criteria for the Severity Classification of Alopecia Areata.

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.

Incidence and survival rates of primary cutaneous malignancies in Korea, 1999-2019: A nationwide population-based study.

Primary cutaneous malignancies are among the most commonly diagnosed types of cancer worldwide. We aimed to examine the incidence and 5-year survival rates of all types of primary cutaneous malignancies in the Korean population. Data from the Korean Nationwide Cancer Registry from 1999 to 2019 were analyzed. The crude incidence rates, age-standardized incidence rates, and 5-year relative survival rates of each type of skin cancer were calculated. A total of 89 965 patients were diagnosed with primary cutaneous malignancies, which was a 7-fold increase from 1999 to 2019. The age-standardized incidence rates increased 3.4-fold in basal cell carcinoma (3.7/100 000 person-years), 2.0-fold in squamous cell carcinoma (1.6/100 000 person-years), 12.0-fold in Bowen disease (1.2/100 000 person-years), and 1.8-fold in malignant melanoma (0.7/10 000 person-years) in 2019. Average annual percentage changes in age-standardized incidence rates were statistically significant in basal cell carcinoma (15.8%), Bowen disease (5.8%), squamous cell carcinoma (5.1%), malignant melanoma (1.2%), melanoma in situ (1.1%), dermatofibrosarcoma protuberans (1.2%), mycosis fungoides (0.5%), primary cutaneous CD30+ T-cell proliferations (0.5%), adnexal and skin appendage carcinoma (0.4%), extramammary Paget's disease (0.2%), and Merkel cell carcinoma (0.2%). The 5-year relative survival rates were the highest in basal cell carcinoma (103.3%), followed by dermatofibrosarcoma protuberans (99.7%) and mycosis fungoides (96.6%), and lowest in angiosarcoma (24.7%). The 5-year relative survival rates steadily increased in extramammary Paget's disease (23.6%), cutaneous B-cell lymphoma (21.3%), mycosis fungoides (20.2%), extranodal NK/T-cell lymphoma, nasal type (18.1%), and malignant melanoma (16.1%) from 1996-2000 to 2015-2019. Most primary cutaneous malignancies have increased in incidence and survival rates in the Korean population, but to varying extents depending on the type of skin cancer.

Knowledge and the behavioral patterns of photoprotection among Koreans with skin disease.

BACKGROUND: Photoprotection is crucial in preventing the development and progression of various skin diseases. However, patients with skin disease have limited awareness of photoprotection. We evaluated the knowledge and behavioral patterns of photoprotection among Koreans with skin diseases. METHODS: A cross-sectional study was conducted in 11 general hospitals across South Korea. The study population consisted of patients aged 19 years or older who visited dermatologic clinics for their skin diseases. A self-administered questionnaire was used to collect patient demographics, knowledge of photoprotection, and photoprotective habits. RESULTS: In this study, 1173 patients with skin cancer, hyperpigmentary disorders, hypopigmentary disorders, or other skin diseases participated. Females scored significantly higher in knowledge of photoprotection compared to males (mean score 8.4 vs. 7.8; p < .001), and younger patients (<50 years) scored higher than older patients (mean score 8.7 vs. 7.5; p < .001). Males also reported longer sun exposure times and lower usage of photoprotective measures (both p < .001). Patients with skin cancer had the lowest mean knowledge score (7.1 ± 2.6) and were less likely to use photoprotective measures compared to other groups (p < .001). In contrast, patients with hyperpigmentation actively avoided sun exposure compared with other groups (p < 0.001). CONCLUSIONS: Knowledge of photoprotection among Korean patients with skin diseases varied depending on the gender, age, and type of skin disease. Their photoprotective behaviors were inadequate, especially among males and those with skin cancer. These findings emphasize the importance of educating and tailoring photoprotection strategies for patients with skin diseases.

Standardized cotton swab sampling with nested quantitative polymerase chain reaction is effective for diagnosing ordinary scabies.

BACKGROUND: Low sensitivity of the PCR assay for diagnosing scabies has been noted because of the difficulty in obtaining tissue containing Sarcoptes scabiei DNA. AIM: To evaluate nested real-time quantitative PCR (nRT-qPCR) with nonexpert-dependent standardized cotton swab sampling (CSW) as a tool for diagnosing scabies. METHODS: All patients underwent dermoscopic and microscopic examination (MS) with scraped sampling (Sc). Patient samples were acquired with a single, dry swab rubbed across the flexor areas of both wrists as well as the eight interdigital spaces and on any suspected scabies lesions. nRT-qPCRs were performed with Sc and CSW samples. RESULTS: Out of 125 patients with suspected scabies, 120 patients were sampled, and 57 were positive (positive with: MS n = 53; nRT-qPCR with Sc n = 52; nRT-qPCR with CSW n = 46) and 63 were negative for scabies. The sensitivities of these tests were 93.0%, 91.2% and 80.7%, respectively, which were not different statistically (P > 0.05). However, upon subsequent monitoring after treatment, the sensitivity of nRT-qPCR with CSW was only 36.6%, which was significantly lower than 83.0% for MS and 92.7% for nRT-qPCR with Sc (P < 0.001). The obtained sequences showed 97%-100% homology with scabies sequences deposited in GenBank. CONCLUSION: CSW with nRT-qPCR shows sensitivity close to MS with scraping performed by experts for diagnosing scabies in an outpatient setting, but not for post-treatment monitoring. CSW with nRT-qPCR may be useful for physicians unfamiliar with a traditional diagnostic method, and for screening an outbreak in community facilities.

Impact of Pediatric Alopecia Areata on Quality of Life of Patients and Their Family Members: A Nationwide Multicenter Questionnaire Study.

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.

Effectiveness of Cytochrome c Oxidase Subunit 1 Gene Nested Polymerase Chain Reaction Compared to Dermoscopy or Microscopy Alone for the Detection and Diagnosis of Sarcoptes scabiei var. hominis Infection.

BACKGROUND: Background: While microscopy (MS) evaluation of skin scrapings has a 100% positive predictive value and specificity by definition for scabies diagnosis, it has low sensitivity. Dermoscopy (DS) has not yet been widely accepted for diagnosis, and long-term clinician training is required. OBJECTIVE: To evaluate the diagnostic validity of cytochrome c oxidase subunit 1 (cox1) gene nested polymerase chain reaction (PCR) as an adjunctive method for diagnosing scabies. METHODS: This was a prospective, single institution study, conducted on a total of 302 skin lesions from 50 patients suspected of scabies at Kangdong Sacred Heart Hospital in Seoul, Korea. DS, MS, and cox1 nested PCR were performed on all patients. RESULTS: Of the 302 lesions, 145 (48.0%) were obtained at first visit and 157 (52.0%) were identified in the course of follow-up visits after treatment. For all lesions, DS and MS sensitivity levels were 55.9% (73/136) and 55.2% (75/136), respectively, with cox1 gene nested PCR considered as 100%. The results of DS and MS identification showed no difference between each other and showed significant difference from that of cox1 gene nested PCR. CONCLUSION: Nested PCR detecting cox1 may be prospectively used to comprehensively diagnose lesions of scabies in clinical practice.

Association between erythema nodosum/ erythema induratum of Bazin and Mycobacterium tuberculosis infection in Koreans.

BACKGROUND: Erythema nodosum and erythema induratum of Bazin are similar inflammatory diseases of the lower extremities. These are clinically distinguishable entities, though overlap can occur. Both diseases are reported to be related to Mycobacterium tuberculosis infection, but it is very difficult to identify Mycobacterium tuberculosis in skin lesions. AIM: This study aimed to develop a new nested polymerase chain reaction targeting the IS6110 insertion sequence of M. tuberculosis to improve the M. tuberculosis detection rate in skin lesions of erythema nodosum or erythema induratum of Bazin. METHODS: From May 2016 to Jan 2018, 14 patients with clinically suspicious erythema nodosum or erythema induratum were enrolled in the study. Two cases were classified as erythema nodosum and 12 as erythema induratum. Individual patients were subjected to a 4-mm punch biopsy, and their venous whole blood was sampled immediately after diagnosis. RESULTS: Eight patients were tested for M. tuberculosis using QuantiFERON, of which seven (87.5%) were positive. IS6110-nested polymerase chain reaction on all 14 patients identified 11 (78.6%) positive cases. Four of the eight (50%) individuals tested with QuantiFERON were also positive in the IS6110 nested polymerase chain reaction. The difference between the outcomes of the QuantiFERON and the IS6110-nested polymerase chain reaction tests was not statistically significant. There was also no significant agreement between the results of both assays. Sequencing the IS6110-nested polymerase chain reaction products showed a 97%-100% nucleotide sequence identity with the H37Rv genome. CONCLUSION: It is important to test for tuberculosis in patients with multiple tender subcutaneous nodules on their lower extremities in high-burden tuberculosis countries like Korea. LIMITATIONS: We need to register more suspicious patients to verify the association between erythema nodosum/erythema induratum of Bazin and M. tuberculosis. Furthermore, it is necessary to improve the more sensitive polymerase chain reaction technique to identify M. tuberculosis directly in cutaneous lesions.

The long-term risk of lymphoma and skin cancer did not increase after topical calcineurin inhibitor use and phototherapy in a cohort of 25,694 patients with vitiligo.

BACKGROUND: Topical calcineurin inhibitors have been used to treat vitiligo, either alone or in combination with phototherapy; however, the long-term safety of these agents remains controversial. OBJECTIVE: To investigate the risk of lymphoma and skin cancer in vitiligo patients who received topical calcineurin inhibitors or phototherapy. METHODS: A multicenter retrospective cohort study of 25,694 vitiligo patients who received topical calcineurin inhibitors or phototherapy for 6 weeks or more between 2001 and 2019 was performed. Cumulative doses of topical calcineurin inhibitors and total phototherapy sessions were determined. Outcomes were the development of lymphoma or skin cancer after enrollment, confirmed through chart review and pathology reports. RESULTS: During 95,203 person-years, 13 cases of lymphoma, 22 of actinic keratosis, 15 of nonmelanoma skin cancer, and 5 of melanoma were observed. The risk of lymphoma and skin cancer was not significantly increased by topical calcineurin inhibitor dose or phototherapy sessions. The interaction between the topical calcineurin inhibitors and phototherapy was not associated with an increased risk of skin cancer. LIMITATIONS: Retrospective study, individual follow-up duration less than 4 years, and no adjustment for comorbidities and medication history. Not generalizable to other races. CONCLUSION: The long-term risk of skin cancer or lymphoma was not associated with the use of topical calcineurin inhibitors, phototherapy, and both treatments in combination in patients with vitiligo.

Perceptions and Behavior Regarding Skin Health and Skin Care Products: Analysis of the Questionnaires for the Visitors of Skin Health Expo 2018.

BACKGROUND: Social standards for skin health have changed and have led to a rise in the general population's interest to achieve flawless skin. OBJECTIVE: To survey the Korean public's perception of skin health and dermatologists and skin-health-related behaviors. METHODS: A total of 355 participants of the Skin Health Expo 2018, held by the Dermatological Research Foundation of the Korean Dermatological Association from September 14 to 16, 2018, completed a questionnaire that assessed demographics, status, and behaviors regarding skin health. The questionnaire also included lifestyle characteristics, satisfaction, behavioral factors, and perceptions regarding skin-care products. RESULTS: Participants were using various skin-care products including toners, lotions, hydrating or nutrition creams, sunscreens, essences, serums, facial masks and packs, body, hand, and foot moisturizers, eye creams, and hair products. The participants believed that the most reliable source of information on skin-care product recommendations was the dermatologist (41.55%). However, purchases were also being made at skin-care product stores (27.64%) based on the recommendation of a friend or acquaintance (40.11%). The results also revealed that 23.8% of participants experienced side effects from using skin-care and cosmetic products, and about 40% of participants could not yet distinguish hospitals run by dermatologists. CONCLUSION: Demand for skin-care products has been increasing, and dermatologists should provide proper information about skin health to prevent adverse effects from skin-care products. Educational and informative activities, such as the expo planned by dermatologists, are necessary to improve skin health in the general population.

Isolated Plantar Vein Thrombosis Resembling a Corn with a Bruise.

Plantar vein thrombosis, rarely-reported disease, is usually accompanied by pain and tenderness in the plantar region and should be differentiated from other dermatological conditions causing plantar pain, such as hemorrhagic corn/callus, plantar epidermal cyst, verruca, or plantar fibromatosis. A 52-year-old man presented with a violaceous tender subcutaneous nodule overlying a hyperkeratotic plaque on his sole. Initially, he thought it was a corn and applied keratolytic agents, which failed to work. Sonography revealed a well-demarcated mass with increased peripheral vascularity. His pain was relieved after a complete wide excision, which confirmed the mass to be plantar vein thrombosis after histopathological examination.

Regional Control of Hairless versus Hair-Bearing Skin by Dkk2.

Haired skin is a defining characteristic of mammals. However, some specialized skin regions, such as human palms, soles and ventral wrist, and mouse plantar foot, are entirely hairless. Using mouse plantar skin as a model system, we show that the endogenous secreted Wnt inhibitor DKK2 suppresses plantar hair follicle development and permits the formation of hairless skin. Plantar skin retains all of the mechanistic components needed for hair follicle development, as genetic deletion of Dkk2 permits formation of fully functional plantar hair follicles that give rise to external hair, contain sebaceous glands and a stem cell compartment, and undergo regenerative growth. In the absence of Dkk2, Wnt/ß-catenin signaling activity is initially broadly elevated in embryonic plantar skin and gradually becomes patterned, mimicking follicular development in normally haired areas. These data provide a paradigm in which regionally restricted expression of a Wnt inhibitor underlies specification of hairless versus hairy skin.