Chao-Chun Yang

National Cheng Kung University Hospital · Department of Dermatology

Hair follicle stem cells in the epithelial bulge are responsible for the continual regeneration of the hair follicle during cycling. The bulge cells reside in a niche composed of dermal cells. The dermal compartment of the hair follicle consists of the dermal papilla and dermal sheath. Interactions between hair follicle epithelial and dermal cells...

Obesity is a risk factor for multiple health problems, but its association with androgenetic alopecia (AGA) remains controversial. We sought to determine the association between body mass index (BMI) and alopecia severity in men with AGA and early-onset AGA. A cross-sectional study was conducted. The medical charts and photographs of men with a cli...

Adipose tissue encircles the lower portion of anagen hair follicles and may regulate hair cycle progression. Since leptin is a major adipokine, its level of expression from the dermal white adipose tissue during hair cycle progression was studied. The result shows that leptin level is differentially expressed during hair cycle, the lowest in early...

In addition to genetics and androgens, novel factors could play a role in androgenetic alopecia (AGA). This study aims to investigate the association between plasma leptin level with the risk and severity of AGA in men. Forty-eight subjects were enrolled including 29 AGA and 19 non-AGA subjects. The plasma leptin level was significantly higher in A...

Androgenetic alopecia (AGA), also known as common baldness, is characterized by a marked decrease in hair follicle size, which could be related to the loss of hair follicle stem or progenitor cells. To test this hypothesis, we analyzed bald and non-bald scalp from AGA individuals for the presence of hair follicle stem and progenitor cells. Cells ex...

Scalp hair density and hair diameters were the two key parameters to the diagnosis of hair loss diseases, including androgenetic alopecia (AGA). To comprehensively map the hair density and the ratio of terminal‐to‐vellus hair numbers (T/V ratio) on different scalp sites in subjects of different genders, ages, body mass index, and stages of AGA. The...

Introduction: Psoriasis in different body regions displays varying therapeutic responses to biologics, whereas currently relevant studies remain scarce. Methods: We retrospectively reviewed the treatment responses of patients with moderate-to-severe psoriasis, who completed the two-year reimbursed ustekinumab or secukinumab treatment in two medi...

Acute rheumatic fever (ARF) is considered as a disorder of children, and attacks in adults are usually a recurrence of disease acquired in the child’s life. Although the incidence of ARF in children has a decreasing trend in developed countries, resurgent and sporadic epidemics still occur in adults. The first attacks of ARF in adult patients witho...

In clinical settings, although Psoriasis Area and Severity Index (PASI) scoring system can provide a quick visual assessment of the severity of psoriasis vulgaris, there is still a strong demand for higher efficiency and accuracy in quantifying the inflammation status of psoriatic lesions. Currently, there are already commercial systems, such as th...

Background: Brown algae have been used as food and traditional Chinese medicine for thousands of years and it is known to contain a bioactive component - fucoidan. However, little is known about the effect of fucoidan on cell differentiation and proliferation, particularly in topical application. Given that, this study focused on investigating the...

Alopecia areata (AA) is a common, nonscarring type of alopecia that can cause chronic and severe hair loss in some cases. Although there is no standard established protocol for the use of corticosteroid pulse therapy, it has been reported to be an effective and well-tolerated treatment option for patients with severe AA. This study retrospectively...

Background: Female pattern hair loss (FPHL) is the main cause of alopecia in women and has a debilitating impact on the quality of life. However, certain comorbid conditions causing hair loss are often masked by FPHL and may remain undetected. Hence, it is imperative to identify them to administer appropriate treatment. The necessity of laboratory...

Annular configuration is conspicuous in the clinical manifestation of many skin diseases and can be helpful for the diagnosis and differential diagnosis. Variations may include arciform, ring-form, annular, circinate, serpiginous, gyrated, polycyclic, targeted or figurate forms, in different colors, sizes and numbers, with various textures and surf...

Hidradenitis suppurativa is a cutaneous chronic inflammatory disease that is estimated to affect about 1% of the population and caused pain, malodorous discharge, disfigurement, and poor quality of life with psychosocial problems. The typical features are recurrent painful nodules, abscesses, and sinus tracts on the axillae, groins, gluteal areas,...

Background: Hidradenitis suppurativa (HS) is a severe dermatological disease that significantly reduces life quality. However, the etiology of this disease remains largely unknown. Objectives: We sought to identify the factors associated with clinical presentation and the severity of HS. The features of HS between genders and smokers/nonsmokers wer...

Hidradenitis suppurativa (HS), or acne inversa, is a painful and recurrent inflammatory cutaneous disorder involving the terminal hair follicles of intertriginous and gluteal areas. Epidemiological studies have revealed geographic differences regarding the demographic and clinical characteristics of HS.1 The gender distribution of HS patients is di...

Psoriasis affects more than 125 million people worldwide, and the diagnosis and treatment efficacy evaluation of the disease mainly rely on clinical assessments that could be subjective. Our previous study showed that the skin erythema level could be quantified using diffuse reflectance spectroscopy (DRS), and the hemoglobin concentration of most p...

SR‐T100 gel, containing solamargine extracted from Solanum undatum (synonym: Solanum incanum), had good therapeutic effects on actinic keratosis (AK) in human and ultraviolet B‐induced papilloma in mice. This study aimed to investigate the immunohistochemical changes in the human skin after SR‐T100 treatment. An immunohistochemical study was perfor...

There is a paucity of data focusing on geriatric psoriatic patients. The clinical features were different among those with early‐onset psoriasis and elderly‐onset psoriasis among the geriatric population. From 2014 to 2018, a total of 290 geriatric psoriatic patients were retrospectively enrolled in our study. They were subclassified into two group...

Eosinophilic pustular folliculitis (EPF) is classified into Ofuji disease, immunosuppression-associated EPF, and infancy-associated EPF. The association of EPF with Demodex infestation is rarely reported. We report five cases of EPF with Demodex overgrowth. All patients were young females presenting with recurrent, itchy papulopustules on the face...

Background Real-world clinical data on psoriasis patients receiving different biological agents is needed, especially in Asian populations. Objectives Our aim is to compare and analyze the efficacy and safety profile of four biological agents (etanercept, adalimumab, ustekinumab and secukinumab) in a real-world setting in Taiwan. Methods We retro...

Psoriasis affects more than 125 million people worldwide, and the diagnosis and treatment efficacy evaluation of the disease mainly rely on clinical assessments that could be subjective. Our previous study showed that the skin erythema level could be quantified using diffuse reflectance spectroscopy (DRS), and the hemoglobin concentration of most p...

Autosomal recessive dystrophic epidermolysis bullosa (RDEB) is characterized by recurrent mucocutaneous blistering with non-healing ulcers which are often complicated by squamous cell carcinoma (SCC). Despite having as high as 80% death rate from SCC, RDEB still does not have an effective treatment. We report on the efficacy of single follicular un...

The physical properties of a tissue, including hardness, play an important role in development, homeostasis and disease pathogenesis.1 For hair follicles, physical properties of the surrounding tissue regulates hair morphogenesis and growth.2 However, little is known about the role of tissue hardness in hair loss diseases. Androgenetic alopecia (AG...

Hepatitis B virus (HBV) infection is a critical public health issue worldwide. The prompt recognition of skin diseases associated with HBV enables the earlier diagnosis of undetected HBV infection. This review article aims to provide a guide for physicians to increase awareness of possible HBV infection when encountering skin diseases. The frequenc...

Background: The increasing use of biologics is accompanied by a risk of hepatitis B (HBV) and C virus (HCV) reactivation. Objective: To determine the predictors of HBV and HCV reactivation in psoriasis patients receiving biologics. Methods: This study screened 2060 psoriasis patients (3562 treatment episodes) who were taking biologics from 200...

Acne keloidalis (AK) is one of the primary cicatricial alopecias and predominantly affects men of African descent. Reports in Asians are scant. This study aimed to retrospectively review the clinical and histopathological features of AK patients in southern Taiwan and identify the pathognomonic features of AK. There were 15 patients with histopatho...

First reported from Taiwan mistakenly as acral acanthosis nigricans in 1991, pigmented carpotarsal hyperkeratosis or hyperkeratosis nigricans carpi et tarsi displays a peculiar distribution of velvety brown‐gray hyperpigmented plaques symmetrically on the flexural side of the wrists and ankles and on the dorsal sides of the hands and feet. A marked...

Zusammenfassung Hintergrund und Ziele Perifolliculitis capitis abscedens et suffodiens (PCAS; im englischen Sprachraum meist als „dissecting folliculitis“ oder „dissecting cellulitis“ bezeichnet) ist eine seltene Krankheit, die mit entstellender vernarbender Alopezie einhergeht. Ziel dieser Studie war es, die Merkmale der PCAS zu untersuchen und e...

Background and Objectives Dissecting folliculitis (DF) or dissecting cellulitis of the scalp is regarded as a rare disease with disfiguring scarring alopecia. This study aimed to analyze the features of DF and to propose a classification to define its severity. Patients and Methods A hospital‐based retrospective study was conducted. Patients with...

Angiosarcoma is a rare soft tissue sarcoma of poor prognosis. A retrospective single-center study was conducted to characterize cutaneous angiosarcoma. Twenty patients were enrolled. The mean age was 76 years and male to female ratio 3:1. Ninety percent had primary angiosarcoma. Scalp was the most commonly involved site. Metastatic disease was note...

Introduction: Polyarteritis nodosa (PAN) is a difficult-to-treat rheumatology disorder, and biologic agents have been used in such patients with a treatment failure or the disease relapse. Case presentation: We report a 42-year-old male Han Chinese who received adalimumab (ADA) alone during his vasculitis relapse, manifesting with weight loss, a...

Background: Currently available topical treatments for actinic keratosis (AK) are associated with substantial side-effects. Objectives: To evaluate the efficacy and safety of topical SR-T100 gel in treating AK. Methods: A multicenter, randomized, double-blinded phase III trial was conducted. Patients with at least two clinically visible AK wer...

Mechanical forces are known to regulate homeostasis of the skin and play a role in the pathogenesis of skin diseases. The epidermis consists of keratinocytes that are tightly adhered to each other by cell junctions. Defects in keratins or desmosomal/hemidesmosomal proteins lead to the attenuation of mechanical strength and formation of intraepiderm...

Primary scarring alopecia (PSA) is caused by irreversible damage to the hair epithelial stem cells that reside in hair follicles. There is limited published work regarding PSA amongst the Asian population. The aim of this study was to evaluate the clinical features and to characterize the subtypes of PSA in southern Taiwan. In this retrospective ca...

Background: Telogen effluvium (TE) is nonscarring alopecia caused by medications, metabolic or hormonal stress or severe systemic infections. An outbreak of dengue affected > 1% of population in Tainan in 2015 and clusters of patients with dengue-associated TE effluvium were presented in our clinic after the outbreak. Objectives: We sought to chara...

Immune reconstitution inflammatory syndrome (IRIS) is an excessive immune reaction to a pre-existing infection following the initiation of highly active antiretroviral therapy (HAART) in human immunodeficiency virus (HIV)-infected patients. Molluscum contagiosum-associated IRIS is rare. We report a new case and review the five other reported cases....

Background: Pregnancy is associated with significant changes in hormones and metabolism which can also exert impact on the skin. Objectives: The study was aimed to evaluate the facial acne severity during pregnancy and post-partum period and to identify risk factors for acne in pregnancy. Methods: A hospital-based prospective study on pregnant...

Spatially resolved diffuse reflectance spectroscopy (SRDRS) has been employed to quantify tissue optical properties and its interrogation volume is majorly controlled by the source-to-detector separations (SDSs). To noninvasively quantify properties of dermis, a SRDRS setup that includes SDS shorter than 1 mm is required. It will be demonstrated in...

Diffuse reflectance spectroscopy (DRS) has been utilized to study biological tissues for a variety of applications. However, many DRS systems are not designed for handheld use and/or relatively expensive which limit the extensive clinical use of this technique. In this paper, we report a handheld, low-cost DRS system consisting of a light source, o...

This case report describes the occurrence of a cutaneous infection caused by plant pathogen Colletotrichum gloeosporioides that was successfully treated with oral itraconazole.Colletotrichum species are common pathogens for plant anthracnose but have recently emerged as a human opportunistic pathogen causing keratitis and subcutaneous fungal infect...

The pathogenesis and ideal treatment of keloid are still largely unknown, and it is essential to develop an objective assessment of keloid severity to evaluate the therapeutic response. We previously reported that our diffuse reflectance spectroscopy (DRS) system could assist clinicians in understanding the functional and structural condition of ke...

The treatment response of alopecia areata (AA) is often unpredictable. The aim of this study was to report the efficacy of an excimer lamp in treating AA. Seventeen AA patients were included. The overall response rate was 41.1%, and the satisfactory response rate was 29.4%. In patients with severe AA, the response rate was 50%. The therapeutic effe...

Genetic studies suggest that the major events of human hair follicle development are similar to those in mice, but detailed analyses of this process are lacking. In mice, hair follicle placode 'budding' is initiated by invagination of Wnt-induced epithelium into the underlying mesenchyme. Modification of adherens junctions is clearly required for b...

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Acne is one of the most common skin diseases. Many epidemiologic studies and twin studies have provided substantial evidence about the genetic influence in the development of acne [1-5], at least in certain stages of acne such as neonatal acne, teenage acne [6], adult persistent acne, or in special forms of acne such as acne comedonica, acne invers...

Background: The preferential occurrence of certain skin neoplasms on the scalp of children raises concerns from their parents and warrants special diagnostic and therapeutic approaches. Objective: To explore the demographic and clinical characteristics of scalp neoplasms in the pediatric population, with attention to malignant tumors and systemi...

Spontaneous recovery of severe alopecia areata is rare and the condition is difficult to treat. The aim of this study is to investigate and compare the effects and safety of steroid pulse therapy between oral and intravenous administrations between 1999 and 2010 at the Department of Dermatology, National Cheng Kung University Hospital. Data were re...

Arsenic may cause serious environmental pollution and is a serious industrial problem. Depending on the dosage, arsenic may trigger the cells undergoing either proliferation or apoptosis-related cell death. Because of lack of the proper animal model to study arsenic induced tumorigenesis, the accurate risk level of arsenic exposure has not been det...

Aging is an accelerating and escalating phenomenon and reality worldwide. According to the World Health Organization, over 2 billion people will be aged 60 years and older by 2050. Aging changes every aspect of human life and influences all medical disciplines. Geriatrics and gerontology are gaining growing significance in daily practice. The patho...

Background Alopecia areata (AA) is regarded to be mediated by autoimmune process, and manifests as patchy non-scarring hair loss with occult onset. Little is known about AA occurring later in life. Objective To define the characteristics of late-onset AA. Methods Patients with first onset of AA at age 50 years and above were retrospectively recruit...

Hair loss is a topic of daily talk even among the elderly, especially for women, as population aging is a trend worldwide. Hair loss in the elderly has its distinctive features and an early treatment is essential for an optimal cosmetic effect. Greying of hair is usually the first manifestation of hair aging, while the number of hair follicles and...

A 32-year-old Taiwanese man presented to our clinic with a 6-month history of linear hair loss in a wavy and curved pattern across the parietal and occipital scalp, resembling the distribution of Blaschko's lines. Physical examination showed interfollicular erythema and follicular plugging without skin atrophy or sclerotic change. Histopathology re...

Hair loss in elderly women has been becoming a major topic in the daily practice of dermatology. Aging of hair follicles seems to affect hair growth and pigmentation, the molecular mechanisms of which remain to be elucidated. Further senile changes in physiology and immunity may influence the onset and course of hair diseases. Some preexisting dise...

Pityriasis rubra pilaris (PRP) is a papulosquamous dermatosis uncommon in juveniles. Large-scale studies are limited, especially from Asian countries. We sought to analyze the clinical manifestations of juvenile PRP in Taiwanese patients and compare them with reported series in the literature. The diagnosis of juvenile PRP was made based on clinica...

Type 2 segmental manifestation of autosomal dominant dermatoses refers to pronounced segmental lesions superimposed on the ordinary nonsegmental phenotype, indicating loss of heterozygosity occurring at an early stage of embryogenesis. We describe a 20-year-old Taiwanese woman with typical lesions of neurofibromatosis type 1 (NF1) in the form of ch...

The regulation of the cutaneous steroidogenesis in patients with androgenetic alopecia remains largely unclear. The purpose of this study was to quantify the expression of the sex-determining genes in different scalp areas. Paired scalp specimens from frontal and occipital scalp areas of 10 patients were examined by real-time RT-PCR for mRNA expres...

The human skin, especially the sebaceous gland, is a steroidogenic organ similar to the gonads and adrenal cortex, possessing all the enzymes required for steroid sex-hormone synthesis and metabolism. Factors regulating cutaneous steroidogenesis associated with disease status remain largely unknown. We hypothesized that transcription factors involv...

To report a rare case of combined hypersensitivity syndrome and pure red cell aplasia (PRCA) following allopurinol therapy. A 43-year-old woman with underlying mesangioproliferative glomerulonephritis developed fever, generalized morbilliform rash, leukocytosis with marked eosinophilia, and hepatic dysfunction 3 weeks after starting allopurinol the...

Persistent plaques and linear pigmentation have been reported as specific skin lesions in some patients with adult-onset Still's disease (AOSD). We sought to characterize the histologic findings of AOSD-associated persistent rash in 11 cases and correlate the histologic findings with the clinical features. From 1988 to 2004, 17 cases fulfilling Yam...

Androgenetic alopecia (AGA) and benign prostatic hyperplasia (BPH) are both androgen-dependent disorders, displaying in situ high levels of dihydrotestosterone with a good therapeutic response to finasteride. Embryological development of both the hair follicle and the prostate depends on mesenchymal-epithelial interaction, which is influenced by th...