Sewon Kang

Johns Hopkins University, Baltimore, Maryland, United States

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Publications (125)695.65 Total impact

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    ABSTRACT: In patients with darker skin types (Fitzpatrick phototypes III-VI), acne is often accompanied by post-inflammatory hyperpigmentation (PIH). Further, acne-related pigmentation can pose a greater concern for the patient than the acne lesions. There has been little formal study of this acne-related PIH. Recently, the Asian Acne Board - an international group of dermatologists with interest in acne research - made a preliminary evaluation of the frequency and characteristics of PIH in seven Asian countries. A total of 324 sequential acne subjects were evaluated for the presence of PIH. The majority (80.2%) of subjects had mild to moderate acne and there were more females than males (63.0% vs 37.0%). In this population of patients consulting a dermatologist for acne, 58.2% (188/324) had PIH. The results also showed that pigmentation problems are often long lasting: at least 1 year for more than half of subjects and 5 years or longer in 22.3%. In accordance with our clinical experience, patients reported that PIH is quite bothersome, often as bothersome or more so than the acne itself and sometimes more problematic. Excoriation was commonly reported by patients, and may represent a modifiable risk factor that could potentially be improved by patient education.
    No preview · Article · Jan 2016 · The Journal of Dermatology
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    ABSTRACT: Background: Perioral wrinkling is commonly reported among older adults, but its objective evaluation and causes remain poorly understood. Objective: We sought to develop a photonumeric scale for perioral wrinkling and to elucidate contributory lifestyle factors. Methods: In this cross-sectional study, we recruited participants for facial photographs and a survey. A gender-specific photonumeric scale for perioral wrinkling was developed and used by 3 graders to evaluate participant photographs. Scores and survey responses were used to create a multiple regression model to predict perioral wrinkling. Results: In all, 143 participants aged 21 to 91 years were enrolled. Intraclass correlation coefficient values for interrater and intrarater reliability were high (>0.8) across 2 trials and 3 graders. A multiple regression model for prediction of perioral wrinkling severity included age, gender, and years of smoking as variables. Limitations: The study was limited by sample size and a predominantly Caucasian study population. Conclusion: We created a photonumeric scale that accounts for gender differences in perioral wrinkling and highlighted contributory variables to photoaging in this anatomical location.
    No preview · Article · Jan 2016 · Journal of the American Academy of Dermatology
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    ABSTRACT: BACKGROUND The shave biopsy using a razor with an open blade is the current standard of care for sampling superficial skin lesions.OBJECTIVE To enhance safety, the authors developed a novel biopsy device with a closed blade design for removing the epidermal layer of skin and evaluated against the open razor blade for tolerability, scarring, and accuracy in histological diagnosis.MATERIALS AND METHODS Shave biopsies were performed using the novel device or razor blade on benign epidermal skin lesions in 10 patients on comparable body parts. Digital photography, colorimetry, scar scale evaluations, and questionnaires were used to evaluate the efficacy and tolerability of the devices.RESULTSFor all patients, accurate histological diagnoses were made regardless of device type. No statistically significant differences were detected between the novel device and razor blade in terms of scar scale assessments, colorimetry, and questionnaire responses. Both patients and the participating dermatologist reported satisfaction with the safety and performance of the novel device. No injuries to the provider occurred with either instrument.CONCLUSION The rotating sphere biopsy device is a potential alternative to the razor blade with comparable tolerability, scarring, and accuracy in histological diagnoses, offering improved safety for patients and health care providers.
    No preview · Article · Oct 2015 · Dermatologic Surgery
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    ABSTRACT: Rosacea is a common chronic inflammatory dermatosis of unclear origin. It has been associated with systemic comorbidities, but methodical studies addressing this association are lacking. We evaluated: (1) the association between rosacea and systemic comorbidities; and (2) if the severity of rosacea is impacted by comorbidities. This was a case-control study: patients with rosacea were matched (1:1) to rosacea-free control subjects by age, sex, and race. Relative risk estimates were calculated using logistic regression as odds ratios with 95% confidence intervals. Among 130 participants (65 patients/65 control subjects), we observed a significant association between rosacea and allergies (airborne, food), respiratory diseases, gastroesophageal reflux disease, other gastrointestinal diseases, hypertension, metabolic and urogenital diseases, and female hormone imbalance. Compared with mild rosacea, moderate to severe rosacea was significantly associated with hyperlipidemia, hypertension, metabolic diseases, cardiovascular diseases, and gastroesophageal reflux disease. This was a case-control study with moderate sample size. Associated medical conditions were self-reported and could not always be confirmed by medication use and medical records. Rosacea is associated with numerous systemic comorbid diseases in a skin severity-dependent manner. Physicians should be aware of these associations to provide comprehensive care to patients with rosacea, especially to those with more severe disease. Copyright © 2015 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.
    No preview · Article · Aug 2015 · Journal of the American Academy of Dermatology
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    ABSTRACT: Elderly melanoma patients are known to have lower survival rates than younger patients with melanoma. Paradoxically, a few recent studies have shown a lower frequency of sentinel lymph node (SLN) positivity in older individuals. This is the first analysis of a large national sample to examine the relationship between SLN metastasis and melanoma death across all age groups. The U.S. Surveillance Epidemiology and End Results (SEER) Databases were queried to examine SLN biopsy and mortality outcomes in 158,813 melanoma cases reported from 2003 to 2011, the most current data available in SEER. In bivariate analyses of the 47,577 cases with coded tumor depths and nodal surgery, increasing age varied directly with melanoma death and inversely with SLN positivity, for tumor depths >1 mm (P < 0.001). In multivariate regression analyses, 60-79 year-olds were more likely to die of melanoma compared with 20-39 year-olds [odds ratio (OR) 1.83, 95 % confidence interval (CI) 1.64-2.05], but they were less likely to be SLN-positive (OR 0.62, 95 % CI 0.57-0.68). The inverse association between melanoma mortality and SLN positivity was most pronounced at the extremes of age. The finding that increasing age is associated with a higher incidence of melanoma death but a lower incidence of SLN metastasis highlights the need for further study into age-related differences in melanoma biology, immunological surveillance, and host response. It also questions whether the 5- and 10-year survival rates associated with the current melanoma staging system should be stratified by age to predict outcomes more accurately for melanoma patients.
    No preview · Article · May 2015 · Annals of Surgical Oncology

  • No preview · Article · May 2015 · Journal of the American Academy of Dermatology

  • No preview · Article · May 2015 · Journal of the American Academy of Dermatology

  • No preview · Article · May 2015 · Journal of the American Academy of Dermatology
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    ABSTRACT: Aging and sun exposure are the leading causes of skin cancer. It has been shown that epigenetic changes, such as DNA methylation, are well established mechanisms for cancer, and also have emerging roles in aging and common disease. Here, we directly ask whether DNA methylation is altered following skin aging and/or chronic sun exposure in humans. We compare epidermis and dermis of both sun-protected and sun-exposed skin derived from younger subjects (under 35 years old) and older subjects (over 60 years old), using the Infinium HumanMethylation450 array and whole genome bisulfite sequencing. We observe large blocks of the genome that are hypomethylated in older, sun-exposed epidermal samples, with the degree of hypomethylation associated with clinical measures of photo-aging. We replicate these findings using whole genome bisulfite sequencing, comparing epidermis from an additional set of younger and older subjects. These blocks largely overlap known hypomethylated blocks in colon cancer and we observe that these same regions are similarly hypomethylated in squamous cell carcinoma samples. These data implicate large scale epigenomic change in mediating the effects of environmental damage with photo-aging.
    Full-text · Article · Apr 2015 · Genome biology
  • Anna L. Chien · Euphemia W. Mu · Sewon Kang
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    ABSTRACT: The normal structure of skin consists of the epidermis, dermis and subcutaneous fat; these layers protect us from external insults and maintain internal homeostasis. In osteogenesis imperfecta (OI), the normal structure and function of skin are disrupted. Cutaneous manifestations of OI include thinness, translucency, easy bruisability, impaired elasticity and elastosis perforans serpiginosa (EPS). The pathophysiology of OI involves mutations in genes encoding α-chains of type I collagen, the main component of the dermis. Deficiencies in the quantity and structure of collagen are confirmed by histopathologic studies and lead to various presentations of OI. The wide differential for the dermatologic features of OI includes chronologic aging, photoaging, steroid-induced atrophy and other connective tissue diseases. Management of cutaneous symptoms of OI involves gentle skin care, sun protection, off-label use of topical retinoids and targeted treatments for EPS and hyperhidrosis. Future studies are required to determine the efficacy of dermatologic interventions in OI-associated skin conditions.
    No preview · Chapter · Dec 2014
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    ABSTRACT: Post-inflammatory hyperpigmentation (PIH) is a problematic and distressing acne sequela. The difficulty of clinically assessing and managing post-inflammatory hyperpigmentation is especially prevalent in Asian populations. The Asian Acne Board conducted a study to evaluate concordance in diagnosis of post-inflammatory hyperpigmentation in patients with active acne, acne scarring, and pigmentation problems. Seven dermatologists reviewed 64 anonymous clinical photographs projected onto a screen during a single session. Results showed that there were two groups of raters, those who found a high frequency of PIH and those who found a low frequency. There was significant variability in these two groups in rating the presence of PIH, with an average of 30 diagnoses (24%) difference between high- and low-frequency raters. Results of severity ratings showed that while most cases of PIH were assessed as mild, there was marked variability between raters in their assessments of severity. Overall, variability in PIH diagnosis was greatest when active acne was present; in these cases, low PIH raters were more likely to report skin coloration as erythema instead of PIH. These findings uphold the importance of utilizing specific clinical criteria to improve accurate evaluation of skin color and we advocate future research into this area.
    No preview · Article · Oct 2014 · The Journal of Dermatology
  • Flora Poon · Sewon Kang · Anna L. Chien
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    ABSTRACT: PurposePhotoaging is frequently encountered in a dermatologic practice. This systematic literature review aims to explore the etiology of photoaging and address the evidence behind its current management.MethodsA comprehensive search of MEDLINE, EMBASE, UpToDate and the Cochrane Library was conducted. Articles were limited to those relating to photoaging.ResultsThere are two major approaches in the current management of photoageing. This includes strategies to prevent against UV damage (e.g sunscreen) and medications that attempt to reverse existing skin damage (topical retinoids and 5-fluorouracil).Conclusion There has been a large growth in the variety of treatment options in recent years. While it is important for such growth to continue, prevention via sensible photoprotection methods still remains the best current management option.
    No preview · Article · Oct 2014 · Photodermatology Photoimmunology and Photomedicine
  • Article: Photoaging
    Anne Han · Anna L Chien · Sewon Kang
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    ABSTRACT: This article discusses photoaging or premature skin aging from chronic ultraviolet exposure. This is an important cosmetic concern for many dermatologic patients. Clinical signs include rhytids, lentigines, mottled hyperpigmentation, loss of translucency, and decreased elasticity. These changes are more severe in individuals with fair skin and are further influenced by individual ethnicity and genetics. Photoaging may be prevented and treated with a variety of modalities, including topical retinoids, cosmeceuticals, chemical peels, injectable neuromodulators, soft tissue fillers, and light sources.
    No preview · Article · Jul 2014 · Dermatologic Clinics

  • No preview · Conference Paper · May 2014
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    ABSTRACT: Background/objectives: Widespread use of antibiotics in all areas of medicine has led to significant problems with antimicrobial resistance, which have begun to compromise the usefulness of antibiotics. Antibiotics have long been a keystone of acne therapy. There is a large population of patients with acne and antibiotic therapy is often used for long durations; thus, acne therapy results in extensive antibiotic exposure. This article discusses the role of antibiotic therapy in acne from the perspective of how clinicians can best preserve the utility of these important drugs while providing efficacious and safe therapy for acne patients. Methods: Review of literature augmented by expert opinion when literature was sparse. Results: Antibiotic monotherapy (topical or oral) is not recommended due to the availability of clinically superior regimens. Systemic antibiotics are important for managing moderate to severe acne and should be used for a limited duration of time (3-4 months). Topical antibiotics should be paired with benzoyl peroxide to limit potential for resistance. Information gained in recent years about the pathophysiology of acne has shed light on the role of Propionibacterium acnes as well as other key pathogenic pathways such as inflammation. Conclusions: The improved understanding of acne pathogenic mechanisms can and should be applied to develop modern therapeutic approaches that are efficacious and mesh with current public health concerns.
    No preview · Article · Apr 2014
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    ABSTRACT: Importance Solar UV irradiation causes photoaging, characterized by fragmentation and reduced production of type I collagen fibrils that provide strength to skin. Exposure to UV-B irradiation (280-320 nm) causes these changes by inducing matrix metalloproteinase 1 and suppressing type I collagen synthesis. The role of UV-A irradiation (320-400 nm) in promoting similar molecular alterations is less clear yet important to consider because it is 10 to 100 times more abundant in natural sunlight than UV-B irradiation and penetrates deeper into the dermis than UV-B irradiation. Most (approximately 75%) of solar UV-A irradiation is composed of UV-A1 irradiation (340-400 nm), which is also the primary component of tanning beds. Objective To evaluate the effects of low levels of UV-A1 irradiation, as might be encountered in daily life, on expression of matrix metalloproteinase 1 and type I procollagen (the precursor of type I collagen).Design, Setting, and Participants In vivo biochemical analyses were conducted after UV-A1 irradiation of normal human skin at an academic referral center. Participants included 22 healthy individuals without skin disease.Main Outcomes and Measures Skin pigmentation was measured by a color meter (chromometer) under the L* variable (luminescence), which ranges from 0 (black) to 100 (white). Gene expression in skin samples was assessed by real-time polymerase chain reaction.Results Lightly pigmented human skin (L* >65) was exposed up to 4 times (1 exposure/d) to UV-A1 irradiation at a low dose (20 J/cm2), mimicking UV-A levels from strong sun exposure lasting approximately 2 hours. A single exposure to low-dose UV-A1 irradiation darkened skin slightly and did not alter matrix metalloproteinase 1 or type I procollagen gene expression. With repeated low-dose UV-A1 irradiation, skin darkened incrementally with each exposure. Despite this darkening, 2 or more exposures to low-dose UV-A1 irradiation significantly induced matrix metalloproteinase 1 gene expression, which increased progressively with successive exposures. Repeated UV-A1 exposures did not suppress type I procollagen expression.Conclusions and Relevance A limited number of low-dose UV-A1 exposures, as commonly experienced in daily life, potentially promotes photoaging by affecting breakdown, rather than synthesis, of collagen. Progressive skin darkening in response to repeated low-dose UV-A1 exposures in lightly pigmented individuals does not prevent UV-A1–induced collagenolytic changes. Therefore, for optimal protection against skin damage, sunscreen formulations should filter all UV wavelengths, including UV-A1 irradiation.
    No preview · Article · Dec 2013
  • No preview · Article · Dec 2013 · Journal of drugs in dermatology: JDD
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    ABSTRACT: The temporal analysis of changes in biological skin parameters, including melanosome concentration, collagen concentration and blood oxygenation, may serve as a valuable tool in diagnosing the progression of malignant skin cancers and in understanding the pathophysiology of cancerous tumors. Quantitative knowledge of these parameters can also be useful in applications such as wound assessment, and point-of-care diagnostics, amongst others. We propose an approach to estimate in vivo skin parameters using a forward computational model based on Kubelka-Munk theory and the Fresnel Equations. We use this model to map the skin parameters to their corresponding hyperspectral signature. We then use machine learning based regression to develop an inverse map from hyperspectral signatures to skin parameters. In particular, we employ support vector machine based regression to estimate the in vivo skin parameters given their corresponding hyperspectral signature. We build on our work from SPIE 2012, and validate our methodology on an in vivo dataset. This dataset consists of 241 signatures collected from in vivo hyperspectral imaging of patients of both genders and Caucasian, Asian and African American ethnicities. In addition, we also extend our methodology past the visible region and through the short-wave infrared region of the electromagnetic spectrum. We find promising results when comparing the estimated skin parameters to the ground truth, demonstrating good agreement with well-established physiological precepts. This methodology can have potential use in non-invasive skin anomaly detection and for developing minimally invasive pre-screening tools.
    No preview · Article · Feb 2013 · Proceedings of SPIE - The International Society for Optical Engineering
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    ABSTRACT: OBJECTIVE To highlight the prevalence and impact of skin disease at the stump site in patients who have undergone amputation. DESIGN A cross-sectional health questionnaire of Vietnam War veterans with stump dermatoses at least 38 years after major limb amputation. SETTING A research registry of veterans with combat-related amputations who agreed to participate. PARTICIPANTS Recruitment began January 1, 2006, and ended December 31, 2009, with a registry of 416 veterans. MAIN OUTCOME MEASURES Results of a self-reported 35-item questionnaire. Participants were later contacted by telephone or asked to complete a Web survey. RESULTS Of the 247 veterans, 119 (48.2%) reported at least 1 skin problem within the preceding year. The most common were skin breakdown (25.2%), rash (21.8%), and abrasion (21.0%). In addition, 25.2% experienced skin problems more than 50% of the time, and 37.1% had to alter or replace their prosthesis. Stump dermatoses limited or prevented prosthesis use in the preceding year for 55.6% and caused pain or discomfort at the stump site in 61.5%. CONCLUSIONS More than 38 years after major limb amputation, skin complications at the stump site continue to cause significant morbidities and contribute to prosthesis abandonment. The high prevalence of stump dermatoses stresses the importance of disease prevention, early management, and advanced treatment of skin disease.
    No preview · Article · Nov 2012 · Archives of dermatology
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    ABSTRACT: Sox10 is a transcription factor associated with neural crest development. Its expression has been reported in melanocytes and peripheral nerve sheath cells and their associated tumors. To assess Sox10 sensitivity in benign and malignant melanocytic neoplasms of various histologic subtypes and to discern the specificity of Sox10 in distinguishing between melanocytic neoplasms and fibrohistiocytic and histiocytic mimickers. Sox10 expression was examined by immunohistochemistry in 145 cases of formalin-fixed paraffin-embedded tissue, including benign and malignant melanocytic lesions of various histologies and stages (n = 83), fibrohistiocytic and histiocytic lesions (n = 33), and peripheral nerve sheath tumors (n = 19), among others (n = 10). Immunoreactivity with Sox10 was observed in 100% (83/83) of benign and malignant melanocytic lesions of various subtypes, as well as in 100% (19/19) of benign and malignant peripheral nerve sheath lesions. Among the fibrohistiocytic proliferations and histiocytoses examined, Sox10 was negative in all cases (0/33). Sox10 expression did not vary by histologic subtype in nevi or melanoma; however, both the percentage of tumor nuclei demonstrating Sox10 expression and the intensity of expression were inversely correlated with malignant potential (nevi, melanoma in situ, invasive and metastatic melanoma) (P < .001, P = .016, respectively). Malignant peripheral nerve sheath tumors also showed decreased mean Sox10 expression and decreased intensity of expression when compared with benign counterparts (P < .001, P = .021, respectively). This is a retrospective study with 145 cases included. Sox10 is a highly sensitive marker for melanocytic proliferations and may be useful diagnostically when the differential diagnosis includes fibrohistiocytic and histiocytic proliferations demonstrating S100 expression.
    No preview · Article · Feb 2012 · Journal of the American Academy of Dermatology

Publication Stats

9k Citations
695.65 Total Impact Points


  • 2011-2016
    • Johns Hopkins University
      • Department of Dermatology
      Baltimore, Maryland, United States
  • 2011-2015
    • Johns Hopkins Medicine
      • Department of Dermatology
      Baltimore, Maryland, United States
  • 1997-2013
    • University of Michigan
      • • Department of Dermatology
      • • Department of Psychology
      Ann Arbor, Michigan, United States
  • 2009
    • University of Texas Southwestern Medical Center
      Dallas, Texas, United States
  • 1996-2006
    • Concordia University–Ann Arbor
      Ann Arbor, Michigan, United States
  • 2001
    • The University of Manchester
      Manchester, England, United Kingdom
  • 1998
    • University of Illinois at Chicago
      • Department of Dermatology (Chicago)
      Chicago, Illinois, United States