Background: Atopic dermatitis (AD) is characterized by chronic, relapsing skin inflammation (eczema) with itchy sensation. Keratinocytes, which are located at the outermost part of our body, are supposed to play important roles at the early phase of type 2 inflammation including AD pathogenesis. Objective: The purpose of this study was to evaluate whether keratinocytes-derived reactive oxygen species (ROS) could be produced by the allergens or non-allergens, and the keratinocytes- derived ROS could modulate a set of biomarkers for type 2 inflammation of the skin. Methods: Normal human epidermal keratinocytes (NHEKs) were treated with an allergen of house dust mites (HDM) or a non-allergen of compound 48/80 (C48/80). Then, biomarkers for type 2 inflammation of the skin including those for neurogenic inflammation were checked by reverse transcriptase-polymerase chain reaction and western immunoblot experiments. Results: HDM or C48/80 was found to upregulate expression levels of our tested biomarkers, including type 2 T helper-driving pathway (KLK5, PAR2, and NFκB), epithelial-cell-derived cytokines (thymic stromal lymphopoietin, interleukin [IL]-25, IL-33), and neurogenic inflammation (NGF, CGRP). The HDMor C-48/80-induced expression levels of the biomarkers could be blocked by an antioxidant treatment with 5 mM N-acetyl- cysteine. In contrast, pro-oxidant treatment with 1 mM H2O2 could upregulate expression levels of the tested biomarkers in NHEKs. Conclusion: Our results reveal that keratinocytes- derived ROS, irrespective to their origins from allergens or non-allergens, have a potential to induce type 2 inflammation of AD skin. (Ann Dermatol 33(1) 26∼36, 2021)

Background: Acral melanoma occurs on glabrous skin or the nail apparatus and is distinct from ultraviolet-related melanoma due to differing genetic alteration patterns. Although the pathogenesis of acral melanoma is not well understood, mechanical stress is thought to induce acral melanoma. The incidence of gene mutation and promoter methylation has been reported in tumors from acral melanoma; however, an association between genetic/epigenetic alterations and mechanical stress in acral melanoma remains unclear. Objective: To investigate the relationship between clinical/genetic factors and mechanical stress in acral melanoma. Methods: A retrospective review of 52 patients diagnosed with acral melanoma was performed. We reviewed the clinical characteristics of patients, tumor status, and tumor location. Mutations in BRAF, NRAS, and the TERT promoter, along with KIT amplification and PTEN promoter methylation were analyzed in the tumors. Results: The heel (34/52, 65.4%) was the most common anatomical tumor site. Mutations in BRAF (6/48, 12.5%), NRAS (6/49, 12.2%), and the TERT promoter (4/33, 12.1%), along with KIT amplification (3/37, 8.1%) and PTEN promoter hypermethylation (12/48, 25.0%) were observed in the tumors. On the forefoot, heel, and hallux, PTEN promoter hypermethylation was significantly associated with Breslow thickness (p=0.001) and ulceration rate (p= 0.042). On the midfoot and lesser toes, there was no significant difference in Breslow thickness or ulceration rate regardless of PTEN promoter hypermethylation (p>0.05). Conclusion: PTEN promoter hypermethylation is associated with Breslow thickness and tumor ulceration on the forefoot, heel, and hallux in acral melanoma in Korean patients. (Ann Dermatol 33(1) 18∼25, 2021)

Background: Epidermolysis bullosa (EB) is a rare genetic disease with widely different clinical manifestations, but the relationship between genotype and phenotype is not fully understood. In the present study, we recruited a Chinese family in which two members had been diagnosed with localized EB simplex (EBS), with clinical manifestation, including blisters and erosions on the soles of the feet since infancy. Objective: To identify and confirm the genetic variation in a Chinese family diagnosed as localized EBS. Methods: Our study included two patients, other healthy members of the family, and 100 normal controls. Genomic DNA samples were isolated from each participant, and then polymerase chain reaction (PCR) direct sequencing was performed. Results: The results of PCR direct sequencing revealed a novel heterozygous missense mutation in codon 461 of exon 7 of KRT5 (c.1382T>C), which led to an amino acid change (p.L461P) in the patients with EBS but was absent in unaffected family members and 100 unrelated control samples. Conclusion: The present study broadens the mutational spectrum of EBS, and this knowledge could be harnessed for prenatal screening, gene diagnosis, and gene therapy for localized EBS. (Ann Dermatol 33(1) 11∼17, 2021)

Atopic dermatitis (AD) is a chronic, inflammatory cutaneous disease driven by immune dysregulation and skin barrier dysfunction. We are currently experiencing a new era of understanding of the pathogenesis of AD and, as a consequence, a new era of innovation in therapeutics, including small molecules and biologic therapy. Recently, advances in translational research have challenged the traditional AD pathogenesis paradigm of AD being solely a Th2-dominant disease. Other immune pathways seem to play a role in the complex AD pathophysiology, although the clinical relevance of these additional immune pathway abnormalities is unclear. Type 1, type 22, and type 17 pathway activation (with related cytokines/chemokines) have been demonstrated in the skin and blood of AD patients. Type 2 (interleukin [IL]-4, IL-13), IL-31, and type 22 (IL-22) pathway cytokines are increased in AD acute lesions. IL-22 induces both an epidermal hyperplasia at the onset of acute AD and a marked increase in the terminal differentiation S100 genes. This understanding of pathogenesis corresponds to a historic increase in therapeutic development in AD. The extreme clinical heterogeneity and the chronic progression of AD establish the need for newer, safer, and more effective treatments, control the disease, and improve the quality of life of affected patients. (Ann Dermatol 33(1) 1∼10, 2021)

Background: Local hyperthermia is recommended for the treatment of patients with fixed cutaneous sporotrichosis, though the effectiveness and mechanisms of action remain elusive. While neutrophils represent the main inflammatory cells associated with sporotrichosis lesions, the issue of whether hyperthermia is involved with interactions between neutrophils and Sporothrix globosa remains unclear. Objective: To evaluate the effect of local hyperthermia on sporotrichosis and determine whether local hyperthermia involves effects of neutrophils against Sporothrix. Methods: For the in vivo study, mice were infected with yeast cells of S. globosa followed by treatment with local hyperthermia. In vitro, an isolated Sporothrix strain was co-cultured with or without neutrophils and subjected under different temperatures. Immunofluorescence was used to assess the formation of neutrophil extracellular trap (NETs) were formed under these different culture conditions and the number of fungi colony forming units were compared. Results: Hyperthermia was significantly more effective in clearing the lesions in the mouse model, as compared to sham treatment. Neutrophils failed to exert any fungicidal effects against S. globosa in response to hyperthermia. Moreover, NETs were formed after interaction with S. globosa, and the percentage of NETs formed was not significantly different at 41℃ or 37℃. Conclusion: While hyperthermia could serve as an effective therapy for fixed cutaneous sporotrichosis, this ability does not involve the formation of NETs. (Ann Dermatol 33(1) 37∼45, 2021)

Background: Oral alitretinoin is effective in the treatment of chronic hand eczema (CHE), and ≥12 weeks of alitretinoin treatment has been shown to be effective in Korean patients. However, in the real world, a considerable number of patients discontinue alitretinoin, which leads to treatment failure. Objective: To evaluate the compliance rate of alitretinoin treatment and explore common reasons for poor compliance in patients with CHE in the real world. Methods: We retrospectively reviewed the electronic medical records of CHE patients treated with alitretinoin. We defined 'poor-compliance' as subjects who were treated with alitretinoin for <12 weeks and 'good-compliance' as subjects who were treated with alitretinoin for ≥12 weeks. We reviewed the demographics, dose, and duration of alitretinoin usage, efficacy, and reasons for poor compliance. Results: A total of 137 subjects were enrolled, and 77 (56.2%) did not complete the 12-week treatment with alitretinoin. Among them, the non-improvement rate was significantly higher in the poor-compliance group than in the good-compliance group (p<0.01). The main reasons for the alitretinoin cessation in the poor-compliance group were insufficient response (40.8%), followed by high cost (34.7%), and adverse events (24.5%). Conclusion: Alitretinoin appears the preferred longterm treatment option for CHE. Although there are complaints about late efficacy, cost, and side effects, following proper explanation, these should not justify discontinuation. Physicians need to recognize the reasons for poor compliance with alitretinoin for each patient and suggest continuing alitretinoin for the successful treatment of CHE. (Ann Dermatol 33(1) 46 ∼51, 2021)