Facial Dermatoses Associated With Mask-Wearing in the COVID-19 Era: A Nationwide, Cross-Sectional, Multicenter, Questionnaire-based Study.

BACKGROUND: Daily usage of facial masks during coronavirus disease 2019 pandemic influenced on facial dermatoses. OBJECTIVE: This study investigated the impact of mask-wearing habits on facial dermatoses. METHODS: A nationwide, observational, questionnaire-based survey was conducted from July through August 2021, involving 20 hospitals in Korea. RESULTS: Among 1,958 facial dermatoses, 75.9% of patients experienced aggravation or development of new-onset facial dermatoses after wearing masks. In aggravated or newly developed acne patients (543 out of 743), associated factors were healthcare provider, female gender, and a long duration of mask-wearing. Irritating symptoms, xerosis, and hyperpigmentation were more frequently observed in this group. Aggravated or newly developed rosacea patients (515 out of 660) were likely to be female, young, and have a long duration of mask-wearing per day. Seborrheic dermatitis patients who experienced aggravation or de novo development (132 out of 184) were younger, and they more frequently involved the chin and jaw in addition to the nasolabial folds and both cheeks. Contact dermatitis patients (132 out of 147) with aggravation or de novo development tended to be female, involve both cheeks, and complain of pruritus. Aggravated or newly developed atopic dermatitis patients (165 out of 224) were more likely to be female, and had a higher baseline investigator global assessment score before mask-wearing. CONCLUSION: Clinical features and factors related to aggravation were different according to the types of facial dermatoses.

Consensus Report on Truncal Acne: The Korean Acne and Rosacea Society Experts Panel.

BACKGROUND: More than half of acne patients have truncal acne on their chest, back, and shoulders. However, since most studies on acne have focused on the face, data on clinical characteristics and proper management for truncal acne are insufficient. OBJECTIVE: To establish a Korean Acne Rosacea Society (KARS) consensus for experts' perception and treatment patterns of truncal acne. METHODS: We conducted two rounds of the Dephi technique to gather expert opinion and reach a consensus on truncal acne. The first round comprised 48 questionnaires focusing on various aspects such as epidemiology, clinical features, diagnosis, treatment, prognosis and more, while second rounds consisted of 26 questionnaires. RESULTS: A total of 36 dermatologists (36/38 KARS members, 94.7%) completed this survey. In the first-round survey, consensus was reached on 20 out of the 48 questions (41.7%). In the second-round questionnaire, consensus was achieved on 9 of the 26 questions (34.6%). The most unresponsive lesion to truncal acne treatment was scars (atrophic/hypertrophic). The most commonly used treatments for each non-inflammatory and inflammatory truncal acne lesions were selected to use topical retinoids (78.1% of the responders) and oral antibiotics (93.8% of the responders). CONCLUSION: Our study has yielded valuable insights into the epidemiology, clinical manifestations, diagnosis, treatment, and quality of life of patients with truncal acne. We anticipate that this study will inspire further comprehensive research for individuals with truncal acne.

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.

Whole structural reconstruction and quantification of epidermal innervation through the suction blister method and skin-clearing technique.

Three-dimensional (3-D) analysis of intraepidermal nerve fibers (IENFs) is conducted to advance assessment methods for peripheral neuropathies and pruritic skin disorders. The skin-clearing technique was proven to be a reliable method for 3-D imaging of IENFs. Nonetheless, it still requires further improvement in the imaging process. The aim of this study was to standardize the 3-D evaluation method of IENFs and to suggest promising 3-D biomarkers for clinical application. A total of nine healthy individuals were prospectively enrolled. The newly adopted suction blister method was combined with the tissue-clearing technique. The detailed structure of the IENFs was reconstructed and quantified using the neuron tracing software. The suction blister method showed improved linear integrity of IENFs compared with those obtained from the previously used salt-split skin test. The 3-D parameters most significantly related to natural aging were the convex hull two-dimensional perimeter and the total length (both p = 0.020). The meaningful correlations were followed by total volume (p = 0.025), ends (p = 0.026), convex hull 3-D surface, and complexity (both p = 0.030). Thus, the 3-D parameters could be utilized as possible biomarkers to identify ambiguous pathologies of peripheral neuropathies and pruritic skin disorders.

Impact of COVID-19 on Clinicopathological Spectrum of Pityriasis Rosea in Korea.

BACKGROUND: Pityriasis rosea (PR) is a papulosquamous eruption with generally unknown origin but suspected to be related to viral etiologies. The clinicopathological spectrum of several disorders with viral etiologies has been altered after the coronavirus disease 2019 (COVID-19) pandemic. The author group could experience coherent histological alterations in PR after the COVID-19 pandemic. This study aimed to investigate how the clinicopathological findings of PR were changed after the COVID-19 pandemic. METHODS: Patients (n = 11) diagnosed with PR based on the clinical manifestations and skin biopsies between February 2018 and October 2019 and 11 patients in February 2020 and October 2021 were retrospectively analyzed by investigating the medical records. RESULTS: The patients with PR during the COVID-19 pandemic demonstrated statistically significant histopathological alterations from classic brisk and dense infiltration pattern to dormant and sparse infiltration and psoriasiform-dominant patterns (P = 0.019). PR was associated with more frequent pruritus during the pandemic period (P = 0.027). CONCLUSION: In conclusion, PR demonstrated a significant histopathological alteration with more frequent pruritus during the COVID-19 pandemic. The comparative results about clinicopathological findings of PR will provide a useful reference for dermatologists in the diagnostic process of PR in the COVID-19 pandemic.

Three-dimensional imaging for the analysis of human epidermal melanocytes.

Three-dimensional (3-D) analysis of human epidermal melanocytes is required for deeper understanding of melanocytic disorders. The purpose of this study was to standardize 3-D imaging and quantification for the evaluation of epidermal melanocytes. The epidermal specimen was obtained using the suction blister method from a patient with melanocytic nevus on the forearm skin. Cutaneous ACT-PRESTO, the tissue-clearing and labeling technique, was subsequently performed. With the 3-D image analysis program, morphological reconstruction and quantification of selected perilesional and melanocytic nevus areas were possible. The region of melanocytic nevus showed higher numbers of total melanocytic dendrites and similar numbers of cell bodies compared with perilesional area. In addition, the mean area and volume of cell bodies increased in the melanocytic nevus area compared with the results in the perilesional area. The 3-D evaluation method of human epidermal melanocytes can be applied to investigate novel pathologies related to hyper- or hypo-pigmentary disorders.

Incidence and Prevalence of Skin Cancers in South Korea from 2008 to 2016: A Nation-Wide Population Based Study.

Background: In South Korea, there have been few nationwide epidemiologic studies about premalignant actinic keratosis (AK), squamous cell carcinoma in situ (Bowen's disease), nonmelanoma skin cancer (NMSC), malignant melanoma of the skin (MM), Kaposi's sarcoma (KS), connective and soft tissue cancers, or mycosis fungoides (MF). Objective: Using a nationwide population-based study, we attempted to measure the incidence and the prevalence of the above-mentioned tumors in South Korea. Methods: The database we used included all claims in the Korean National Health Insurance program and the Korean Medical Aid program from 2008 to 2016. The International Classification of Diseases, 10th revision (ICD-10) was used to record diagnoses in this database. This data included AK, Bowen's disease, NMSC, MM, KS, connective and soft tissue cancers, and MF. Results: The age-standardized incidence and prevalence rate of AK, Bowen's disease, NMSC, MM, KS, connective and soft tissue cancers, as well as MF increased during the periods we investigated. The incidence and prevalence rate of AK and NMSC have increased two- to three-fold. In the case of Bowen's disease, MM, KS, connective and soft tissue cancers, or MF, we observed no significant tendency in age-standardized incidence or prevalence. Conclusion: We confirmed that the age-standardized incidence and prevalence rates of NMSC and AK tended to increase. These results might contribute to developing preventive and therapeutic strategies for skin cancers and may become a source for further studies.

What type of face mask should we choose in coronavirus disease 2019 pandemic considering photoprotective effectiveness?

BACKGROUND: Wearing a face mask is one of the most effective personal protective strategies to diminish the spread of coronavirus disease 2019 (COVID-19). Several dermatological outcomes were reported because of the prolonged use of face masks, especially due to the constant mask-on policy, but the photoprotective effect of face masks has received less attention. OBJECTIVE: The aim of this study was to provide guidance in the use of face masks by comparing the photoprotective effects of routinely used masks. METHODS: A total of 12 frequently used face masks were tested, including certified respirators, Korea filter (KF)94, KF-anti-droplet (KF-AD), and KF80. The amount of light that penetrates each face mask was measured using a light sensor that can quantify Ultraviolet A (UVA), visible light (VL), and infrared A (IR-A) rays. RESULTS: Black-colored KF94 masks and surgical masks reduced penetration of UVA, VL, and IR-A by approximately 100%. The UVA penetration decreased on average by 95.51%, 90.97%, 85.06%, and 86.41% with white-colored KF94, KF-AD, KF80, and surgical masks, respectively. The VL and IR-A were blocked by approximately 75.58%, 66.16%, 59.18%, and 64.48% with white-colored KF94, KF-AD, KF80, and surgical masks, respectively. CONCLUSION: In conclusion, the different photoprotective effectiveness of face masks was mainly determined by colors, and therefore, black-colored, multi-layered respirators can be recommended in terms of photoprotection in the COVID-19 pandemic. The quantified comparative results will be helpful to the person with pre-existing photo-aggravated dermatosis, especially in the season of the high intensity of sunlight.

A Phase 3, Randomized, Multi-center Clinical Trial to Evaluate the Efficacy and Safety of Neu-BoNT/A in Treatment of Primary Axillary Hyperhidrosis.

BACKGROUND: Botulinum toxin type A is widely used to treat primary axillary hyperhidrosis and has proven to be an effective and safe approach. Onabotulinumtoxin A was approved by the FDA as a treatment for primary axillary hyperhidrosis. This study aimed to evaluate the efficacy and safety of Neu-BoNT/A in subjects diagnosed with primary axillary hyperhidrosis. METHODS: The Hyperhidrosis Disease Severity Scale, gravimetric measurement of sweat, and Global Assessment Scale were analyzed at weeks 4, 8, 12, and 16 to determine the effect of treatment. Adverse events, physical examination, and vital signs were monitored. RESULTS: Subjects treated with Neu-BoNT/A showed statistically significant improvement by all 3 methods at weeks 4, 8, 12, and 16 (P value = 0.00). There were no severe adverse events or significant changes in vital signs, physical examination, or laboratory tests. CONCLUSION: Neu-BoNT/A can be effectively and safely used for primary axillary hyperhidrosis. LEVEL OF EVIDENCE II: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Differences in Clinical Responses to Ustekinumab Treatment among Body Regions: Results from a Real-World Prospective, Observational, and Multi-Center Study in Korea.

BACKGROUND: In psoriasis treatment, not all body regions improve simultaneously after clinical interventions. OBJECTIVE: This study was aimed at evaluating clinical responses across body regions, which may differentially influence patient treatment plans. METHODS: This prospective, observational, and multi-center study was conducted in Koreans who adhered to ustekinumab treatment based on criteria per local label and reimbursement guidelines. A total of 581 were included in this analysis. RESULTS: The mean (±standard deviation) psoriasis area severity index (PASI) score at baseline, age, disease duration, and body surface area (%) were 18.9±9.69, 44.2±13.29 years, 11.3±9.65 years, and 27.8±17.83, respectively. Across the head and neck, upper extremities, trunk, and lower extremities, the correlation between the PASI sub-scores for the upper and lower extremities was the highest (r=0.680). The mean PASI sub-score for the lower extremities was the highest at baseline. PASI90 and PASI100 scores were the highest for the head and neck region, indicating the highest response rates, while those for the lower extremities were consistently low at all visits. CONCLUSION: We found differences in regional ustekinumab responses, with the lower extremities being the most difficult to treat. These findings should be considered in psoriasis treatment.

Different Immunohistochemical Localization of Fatty Acid Binding Protein 5 in Actinic Keratosis Compared with That in Bowen's Disease: A Retrospective Study.

ABSTRACT: Actinic keratosis (AK) and Bowen's disease (BD) are common premalignant lesions of invasive squamous cell carcinoma that have different pathogenesis and clinical significance. Fatty acid-binding protein 5 (FABP5) is responsible for keratinocyte homeostasis and differentiation; however, no study has revealed its expression in AK and BD. Our study aimed to investigate the differential expression and significance of FABP5 in these lesions. Patients with pathologically confirmed cases of AK (n = 37) and BD (n = 12) were included in this study. FABP5 immunostaining pattern was assessed in the normal skin, AK and BD lesions, with a focus on the staining patterns of basal cells, atypical keratinocytes, and uninvolved epidermal keratinocytes. All patients with AK showed negative FABP5 expression in the atypical cells in the basal layer, whereas the uninvolved upper layers showed diffuse, strong FABP5 expression, regardless of the grade of AK. All patients with BD showed heterogeneous and diffuse FABP5 expression in atypical cells of all layers of the epidermis. This study is the first to investigate the role of FABP5 in premalignant skin lesions. The unique immunohistochemical localization of the FABP5 can be a helpful diagnostic marker, and altered fatty acid metabolism may be the key in understanding the different pathophysiology of AK and BD.

An assessment method for dermal structures using cross-polarized light imaging with a green light-emitting diode.

BACKGROUND: Several experimental methods for evaluating dermal structures exist; however, most of these are not used in dermatology clinics because of cost and functional limitations. OBJECTIVE: To propose a simple, non-invasive method for dermal structure evaluation using a green light-emitting diode (LED) with cross-polarized light (CPL) imaging and compare the quality of the images taken using either green or white LED. MATERIALS AND METHODS: Skin specimens were taken from fifteen cadavers. Images were captured using CPL photography with a green or white LED. The Commission International d'Eclairage L*a*b* (CIELAB) values were calculated for each image. The skin specimens were processed and stained with Masson's trichrome to visualize collagen fibers with major image scattering. The images were histologically analyzed, and correlational and regression analyses were performed to determine the relationship between the L* values and histologic measurements. RESULTS: The L* values for the green images were positively correlated with collagen fiber density, reticular collagen bundle diameter, and dermal thickness. They were effective for estimating dermal properties. The L* values for the white images were positively correlated with reticular collagen bundle diameter and dermal thickness. Correlational coefficients for white images were lower than those for green images. In regression analysis, green images showed a higher coefficient of determination (R2 ) for predicting reticular collagen bundle diameter than white images (0.1128 vs. 0.0827). CONCLUSION: Cross-polarized light imaging with a green LED is a simple, non-invasive method for evaluating dermal structures. The use of a green LED was also more effective for image analysis.

A simple morphometric analysis method for dermal microstructure using color thresholding and moments.

BACKGROUND: Proper assessment of dermal collagen fibers by dermatologists and researchers is essential. Histologic evaluation methods have limitations. We present a simple method for measurement of collagen fibers in human skin using Masson's trichrome staining. MATERIALS AND METHODS: Normal skin specimens from a cadaver were processed with Masson's trichrome, which can effectively stain collagen fibers blue with aniline dye. Optical photomicrographs of these slides were analyzed using ImageJ software. Color image processing, a histogram-based function of ImageJ for image segmentation, was performed with color moments thresholding technique. We selected blue areas by adjusting the blue channel to include specific values. The selected areas were highlighted and evaluated. We divided the image into layers of 0.09-mm2 areas from the top to bottom of the dermis. Each area was cropped and evaluated. RESULTS: Quantitative assessment yielded the quantitative size occupied by collagen fibers in an area of 0.09 mm2 . Calculation of the percentage in each area can be used to determine the density of collagen fibers. CONCLUSION: Measurements obtained with our method can be applied to research on dermal collagen fibers. We present a convenient quantitative assessment method for the dermal constituents in Masson's trichrome-stained slides.

Tissue-Clearing Technique and Cutaneous Nerve Biopsies: Quantification of the Intraepidermal Nerve-Fiber Density Using Active Clarity Technique-Pressure Related Efficient and Stable Transfer of Macromolecules Into Organs.

BACKGROUND AND PURPOSE: Cutaneous nerve biopsies based on two-dimensional analysis have been regarded as a creditable assessment tool for diagnosing peripheral neuropathies. However, advancements in methodological imaging are required for the analysis of intact structures of peripheral nerve fibers. A tissue-clearing and labeling technique facilitates three-dimensional imaging of internal structures in unsectioned, whole biological tissues without excessive time or labor costs. We sought to establish whether a tissue-clearing and labeling technique could be used for the diagnostic evaluation of peripheral neuropathies. METHODS: Five healthy individuals and four patients with small-fiber neuropathy (SFN) and postherpetic neuralgia (PHN) were prospectively enrolled. The conventional methods of indirect immunofluorescence (IF) and bright-field immunohistochemistry (IHC) were adopted in addition to the tissue-clearing and labeling method called active clarity technique-pressure related efficient and stable transfer of macromolecules into organs (ACT-PRESTO) to quantify the intraepidermal nerve-fiber density (IENFD). RESULTS: The mean IENFD values obtained by IF, bright-field IHC, and ACT-PRESTO in the healthy control group were 6.54, 6.44, and 90.19 fibers/mm², respectively; the corresponding values in the patients with SFN were 1.99, 2.32, and 48.12 fibers/mm², respectively, and 3.06, 2.87, and 47.21 fibers/mm², respectively, in the patients with PHN. CONCLUSIONS: This study has shown that a tissue-clearing method provided not only rapid and highly reproducible three-dimensional images of cutaneous nerve fibers but also yielded reliable quantitative IENFD data. Quantification of the IENFD using a tissue-clearing and labeling technique is a promising way to improve conventional cutaneous nerve biopsies.

Adult-onset lichen striatus versus adult blaschkitis: a clinicopathological review of 40 cases of acquired blaschkolinear inflammatory dermatosis.

BACKGROUND: Since the first description of adult blaschkitis (AB), the existence of this entity has been a matter of great debate. OBJECTIVES: To compare clinicopathological features of lichen striatus (LS) and AB cases. MATERIALS AND METHODS: We retrospectively reviewed the clinicopathological features of patients who clinically showed linear inflammatory dermatosis along Blaschko's lines based on a skin biopsy registry. RESULTS: Through a process of clinicopathological differential diagnosis, 27 cases of LS, three of AB, eight of linear lichen planus, and two of linear psoriasis were identified. Clinicopathological differences between LS and AB were mostly insignificant except for age at onset and multiple site involvement. In these cases, females were affected more frequently than males. The mean age at onset was 31.6 years, and the most common involved site was the leg. The lesions lasted approximately 8.3 months with few relapses. The most common histopathological finding was perivascular infiltration followed by peri-appendageal infiltration. CONCLUSION: Distinction between LS and AB appears to be unnecessary given their overlapping features.

Markedly Reduced Risk of Internal Malignancies in Patients With Vitiligo: A Nationwide Population-Based Cohort Study.

PURPOSE: Recent studies indicated that the autoimmunity of vitiligo exerts effects on cells other than melanocytes, which confer reduced risks of both melanoma and nonmelanoma skin cancers in patients with vitiligo. However, the risk of internal malignancy in patients with vitiligo has not been elucidated. PATIENTS AND METHODS: We conducted a population-based retrospective cohort study using data from the Korean National Health Insurance claims database obtained from January 2007 to December 2016. All patients age 20 years or older with vitiligo who had at least two contacts with a physician from 2009 to 2016, during which a principal diagnosis was made, were identified (vitiligo group). Controls were randomly selected (two per patient with vitiligo) after frequency matching with the vitiligo group for age and sex during the same period (control group). RESULTS: A total of 101,078 patients with vitiligo and 202,156 controls without vitiligo were included. The incidence rates of internal malignancies were 612.9 and 708.9 per 100,000 person-years in the vitiligo and control groups, respectively. Patients with vitiligo showed a significantly reduced risk of overall internal malignancies (hazard ratio [HR], 0.86; 95% CI, 0.82 to 0.89; P < .001) compared with controls without vitiligo after adjustments for age, sex, and comorbidities. With regard to organ-specific malignancies, patients with vitiligo showed a remarkably decreased risk of cancer in the colon and rectum (HR, 0.62; 95% CI, 0.55 to 0.69; P < .001), ovary (HR, 0.62; 95% CI, 0.46 to 0.83; P < .001), and lung (HR, 0.75; 95% CI, 0.65 to 0.86; P < .001). CONCLUSION: Vitiligo was associated with a reduced risk of overall internal malignancies. These findings suggest that autoimmune diseases, including vitiligo, may provide immune surveillance for the development of cancer beyond the targeted organ.

Quantification of intraepidermal nerve fiber density using three-dimensional microscopy.

Three-dimensional microscopy provides more extended depth of penetration compared with conventional light microscopy and is known to be useful in clinical evaluation of thick biological specimens. Skin nerve biopsy together with the quantification of intraepidermal nerve fibers in multiple thick sections has been widely adopted for evaluating peripheral neuropathies. The aim of the present study was to evaluate the effectivity of three-dimensional microscopy in reducing the required time and inter-rater discrepancies, especially in the case of personnel not familiar with the quantification methods. A total of six cryo-sectioned specimens were analyzed for the study and the skin samples were collected from one patient with postherpetic neuralgia who voluntarily participated in the study. Two investigators, a physician and non-physician assessed the intraepidermal nerve fiber densities and required analysis time using three different methods including direct visualization of tissue slides, and analysis with two- and three-dimensional images. Three-dimensional microscopy could produce images that enabled reliable evaluation of intraepidermal nerve fibers; the accuracy of analysis was statistically comparable between the physician and non-physician (p > .05). Three-dimensional microscopy also enabled the non-physician to proceed meaningfully faster evaluation compared with the direct visualization method (p = .03). Three-dimensional microscopy could be one of the useful methods to improve accuracy and convenience of the analysis of intraepidermal nerve fibers especially appropriate for unaccustomed physician or non-physician. RESEARCH HIGHLIGHTS: Three-dimensional microscopy is capable of producing images with more extended depth of penetration compared with conventional light microscopy and has been known to be suitable for clinical evaluation of thick biological specimens. Cutaneous nerve biopsy and the quantification of nerve fibers in thick sections has been widely adopted for evaluating peripheral neuropathies. Three-dimensional microscopy could be especially appropriate for unaccustomed physician or non-physician to improve accuracy and convenience of the analysis of intraepidermal nerve fibers.

Correlations between histopathologic and dermoscopic findings in Korean actinic keratosis.

Skin biopsy for AK diagnosis is usually performed on only a limited part of the whole lesion. Therefore, a clinical diagnosis is important. According to a study, there is no significant correlation between histopathological and clinical classification system. We examined the correlation between microscopic information and dermoscopic findings to deduce if dermoscopic information reflects histopathologic grade severity. Forty seven patients with histologically confirmed AK were enrolled and positive ratio of red pseudonetwork, rosette, red background and targetoid signs, white-to-yellow scale, white structureless area, and pigmentation from dermoscopic findings were investigated. Furthermore, viable epidermal thickness, vessel lumen dimensions, existence and thickness of ortho- and parakeratosis, degree of sola elastosis, flag sign existence, and Roewert-Huber classification were measured as histologic findings. Red background did not show a significant correlation with vascular dimension or viable epidermal thickness. When targetoid sign was present, vascular dimension was significantly larger but showed no correlation with viable epidermal thickness, parakeratosis or orthokeratosis. Solar elastosis level was significantly higher when white-to-yellow scale was present. According to Spearman's correlation analysis, ortho/parakeratotic thickness showed correlations with each other. The negative correlation between viable epidermal thickness and vascular dimension was also shown. Roewert-Huber histologic AK classification showed no correlation with any factors we checked. Factors considered to be characteristic features of AK in dermoscopy seemed unassociated with histologic AK classification and additional research is needed to determine degree of dysplasia of AK lesions using dermoscopy.

Demographic and clinical features of hidradenitis suppurativa in Korea.

Hidradenitis suppurativa (HS) is a chronic, relapsing, inflammatory skin disorder. Although several epidemiological studies have been conducted in Western countries, such data regarding Asian populations are scarce. In this study, we sought to investigate the demographic and clinical features of HS in Korea. A total of 438 patients, diagnosed with HS from May 2007 to April 2017, were enrolled and the electronic medical record of each patient was reviewed. Male patients were predominant with a male : female ratio of 2.5:1. Mean age of disease onset was 23.9 years and most patients had no family history. The most frequently affected area was the buttocks, followed by axillae and groin. Acne and diabetes mellitus were the most prevalent associated diseases and no patients with inflammatory bowel diseases were observed. In the univariable analysis, male patients had severe diseases compared with females with an odds ratio (OR) of 1.790. Two or more affected body regions were associated with HS severity with an OR of 1.693. While involvement of the perineum (OR, 4.067) and buttocks (OR, 1.471) tended to be associated with increased severity of the disease, the inguinal area (OR, 0.620) showed a tendency to be inversely associated with the severity. In multivariable analysis, identified risk factors were the involvement of the perineum (OR, 3.819) and buttocks (OR, 2.288). Smoking status and high body mass index seemed to be associated with more severe diseases. Our results will provide clinical characteristics of HS patients in Asia and help to broaden understanding of HS.