Background Many ingredients used in cosmetics evoke a comedogenic response. The concept of ‘‘acne cosmetica’’ was developed to link the use of certain ingredients to comedone formation. Various clinical research methods have been suggested for the effective screening of an ingredient that can worsen acne or acneiform eruption and confirm its clinical relevance as to whether it is used as a non‐comedogenic claim. Although comedogenicity assessment has not yet been established, attempts have been made to evaluate the comedogenicity of cosmetic ingredients and find the most appropriate method to evaluate comedogenicity in human skin. Materials and methods Total 6 participants were included in the study. Each participant received patches on the upper back containing cocoa butter. We used reflectance confocal microscopy (RCM) to count the number of microcomedones and follicles induced by cocoa butter. Results The mean value change of microcomedone/follicle by the comedogenic substance was significantly higher than that of the non‐applied site for 2 weeks (p = 0.0419). The mean value changes of the microcomedone diameter caused by the comedogenic substance were significantly larger than those found at the non‐applied site at 2 and 4 weeks (p = 0.0026 and p = 0.0038, respectively). Conclusions We recommend RCM as a non‐invasive real‐time method that is useful for evaluating comedogenicity and early detection of a microcomedone.

Atopic dermatitis (AD) is associated with allergic comorbidities, such as asthma, allergic rhinitis (AR), and allergic contact dermatitis (ACD). The etiology of keloid is largely unknown; however, AD and keloid share inflammatory pathways characterized by T-helper cell 2 cytokines and increased dermal fibroblast activity. The prevalence of keloids has been reported to increase in patients with AD, but it remains controversial. This study aimed to estimate the prevalence of keloids in patients with AD, and compare it with the prevalence of other comorbidities of AD. We assessed the Korean National Health Information Database and medical records including coexisting asthma, AR, and ACD. Single and multiple logistic regression models were created for keloids and each allergic disease. The prevalence of keloids was higher in the AD group than in the control group. Among patients with AD, adolescents and adults had a higher prevalence of keloids than infants and children. The risk of keloids was high with AD alone, and coexisting asthma significantly increased the risk. Similarly, the risk of keloids was higher in AR associated with AD and ACD associated with AD than in AD alone. Thus, among Koreans, patients with AD have a higher risk of keloid development, with coexisting allergic diseases increasing the risk.

Background: Vitiligo is a pigmentary skin disorder characterised by a chronic and progressive loss of melanocytes. Although several theories have been suggested to the pathogenesis of vitiligo, an autoimmune process leading to melanocyte destruction appears most likely. Human leukocyte antigen-G is a non-classic, major histocompatibility complex Class I molecule that plays an important role in the suppression of the immune response. Several recent studies have provided evidences that polymorphisms in the human leukocyte antigen-G gene might be related with autoimmune diseases. Objectives: The aim of this study was to decide whether exonic single nucleotide polymorphisms in human leukocyte antigen-G contribute to the risk of developing non-segmental vitiligo in the Korean population. Methods: To evaluate the associations between exonic single nucleotide polymorphisms (rs1630223 [Ala5Ala] and rs12722477 [Leu134Ile]) of human leukocyte antigen-G and vitiligo, 244 patients with vitiligo and 398 healthy controls were recruited. Genotyping was performed using Fluidigm 192.24 Dynamic Array with EP1 (Fluidigm Corp., CA). The SNP type assay (Fluidigm Corp., CA), which employs allele-specifically designed fluorescences (FAM or VIC) primers and a common reverse primer was applied and the data were analysed using the EP1 single nucleotide polymorphisms genotyping analysis software to obtain genotype calls. Results: Two exonic single nucleotide polymorphisms (rs1630223 and rs12722477) exhibited significant associations with susceptibility and remained a statistically significant association following Bonferroni correction. These two single nucleotide polymorphisms were located within a block of linkage disequilibrium. Haplotypes G-C and A-A comprising rs1630223 and rs12722477 demonstrated a significant association with non-segmental vitiligo. Limitations: The protein expression level of patients with vitiligo and controls was not studied and a replication study of the genetic association in an independent group was not managed. Conclusion: Our results suggest that exonic human leukocyte antigen-G polymorphisms (rs1630223 and rs12722477) are associated with the development of non-segmental vitiligo.

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Atopic dermatitis (AD) is associated with allergic comorbidities, such as asthma, allergic rhinitis (AR), and allergic contact dermatitis (ACD). The etiology of keloid is largely unknown; however, AD and keloid share inflammatory pathways characterized by T-helper cell 2 cytokines and increased dermal fibroblast activity. The prevalence of keloids is known to increase in patients with AD. This study aimed to estimate the prevalence of keloids in patients with AD, and compare it with the prevalence of other comorbidities of AD. We assessed the Korean National Health Information Database and medical records including coexisting asthma, AR, and ACD. Single and multiple logistic regression models were created for keloids and each allergic disease. The prevalence of keloids was higher in the AD group than in the control group. Among patients with AD, adolescents and adults had a higher prevalence of keloids than infants and children. The risk of keloids was high with AD alone, and coexisting asthma significantly increased the risk. Similarly, the risk of keloids was higher in AR associated with AD and ACD associated with AD than in AD alone. Thus, among Koreans, patients with AD have a higher risk of keloid development, with coexisting allergic diseases increasing the risk.