Association between the skin microbiome and lichen striatus hypopigmentation: Cutibacterium acnes as a potential cause.

BACKGROUND: Lichen striatus (LS) is an acquired skin disorder with a linear pattern along Blaschko's lines. It commonly occurs in childhood, and the lesions spontaneously regress within several months. OBJECTIVES: Although up to 50% of LS cases exhibit hypopigmentation that can persist for several months to years, it is unknown why LS is associated with such a high incidence of hypopigmentation compared to other inflammatory skin diseases. Therefore, this study aimed to analyse the differences in the skin microbiome between LS patients with and without hypopigmentation. METHODS: Differences in skin microbiome were analysed using whole genome sequencing of skin biopsies and subsequent bioinformatics analyses. RESULTS: Some microbes commonly found in hypopigmented skin disorders, including Cutibacterium acnes, were more abundant in patients with LS showing hypopigmentation than in those not showing hypopigmentation. CONCLUSIONS: The skin microbiota may be involved in the development of hypopigmentation in LS and may be considered a treatment target to reduce LS duration and hypopigmentation.

High-fluence 1064nm Q-switched Nd:YAG laser treatment for ectopic Mongolian spot.

Q-switched neodymium-yttrium aluminum-garnet (Q-switched Nd:YAG) laser has been reported as an effective treatment for nevus of Ota and acquired bilateral nevus of Ota-like macules (ABNOM). Data on ectopic Mongolian spots have rarely been reported.The present study was performed to investigate the treatment efficacy of a high-fluence 1064 nm Q-switched Nd:YAG laser without tissue whitening in ectopic Mongolian spots.We included 61 patients with ectopic Mongolian spots, and 70 lesions were examined. Thirty-three lesions were treated with a high-fluence 1064 nm Q-switched Nd:YAG laser, and 38 lesions were observed without treatment. The results were assessed using a 5-quantile grading scale and melanin index using a Mexameter®.Mean follow-up duration was 14.1 ± 6.8 months for the treatment group and 17.8 ± 10.0 months for the observation group. Mean 5-quintile grading scale at final follow-up was statistically different (p < 0.001) between the two groups (treatment: 2.85 ± 1.00, observation: 0.49 ± 0.73). There was a significant difference (p < 0.001) in the Δ melanin index (initial melanin index - final melanin index) between the observation (7.1 ± 62.7) and treatment (156.7 ± 78.4) groups.High-fluence Q-switched Nd:YAG laser without tissue whitening showed good results and was well-tolerated in treating ectopic Mongolian spots.

Geographic differences in atopic dermatitis risk between urban and rural area: A systematic review and meta-analysis.

Atopic dermatitis is the most common chronic inflammatory skin disease affecting children. Some studies have reported a higher risk of atopic dermatitis in urban areas than in rural areas. We systematically reviewed and carried out a meta-analysis to investigate the differences in the development of atopic dermatitis between urban and rural areas. The search was performed on April 19, 2021, using Embase and MEDLINE databases. Eligible for inclusion were observational studies. Subgroup analyses were performed for age, publication year, and country. We identified 2,115 studies, and 43 studies with 1,728,855 subjects were finally included. Urban residency was associated with an increased risk of atopic dermatitis, with an odds ratio of 1.56 (95% confidence interval, 1.43-1.71). A significantly increased risk was observed only in children, with an odds ratio of 1.55 (95% confidence interval, 1.39-1.73), but not in adults, with an odds ratio of 1.29 (95% confidence interval, 0.99-1.67). The risk has increased in recent decades, with a higher risk in developing countries (odds ratio, 1.95) compared to developed countries (odds ratio, 1.35). Our study provides evidence of an association between atopic dermatitis and urban compared to rural living.

Review of the reasons for and effectiveness of switching biologics for psoriasis treatment in Korea.

Background Switching of biologics in patients has become common in clinical practice. Objectives This study investigated the reasons for and effectiveness of switching biologic agents during the treatment of psoriasis. Methods We retrospectively reviewed patients with psoriasis who were treated with biologics at Pusan National University Hospital and Chosun University Hospital from March 2012 to June 2020. We assessed their demographics and treatment characteristics (reasons for switching biologics and efficacy of the first- and second biologic agents). Results Of the 162 psoriatic patients treated with biologic agents for more than 52 weeks, 35 required a switch to another biologic agent. The reasons for switching biologic agents were inefficacy (n = 30), adverse events (n = 2) and others (n = 3). The mean psoriasis area and severity index (PASI) score was 12.1 at the start of the second biologic and 3.4 at 14-16 weeks later. Patients were more likely to switch to another biologic agent when they exhibited a high initial psoriasis area and severity index score and concomitant psoriatic arthritis. Limitations As a retrospective study, there were some limitations such as lack of a placebo control group and the time point of 14-16 weeks being somewhat early to judge the effect of the biologics. Conclusions The most common reason for switching biologic agents in Korea was treatment inefficacy, especially secondary failure. Despite the inefficacy of previous biologic agents, switching to a different agent may be an efficacious approach.

A Novel Mutation in the MBTPS2 Gene Resulting in Ichthyosis Follicularis, Atrichia, and Photophobia Syndrome.

Ichthyosis follicularis, atrichia, and photophobia (IFAP) syndrome is a rare genetic disorder caused by mutations in the MBTPS2 gene. It is characterized by ichthyosis and alopecia from birth. Photophobia may be present in infancy or early childhood. Its mode of inheritance is X-linked recessive; thus, it mostly affects male. The disease severity varies, ranging from mild cases limited to the skin to the severe variant involving multiple extracutaneous features. A 7-year-old boy presented with scanty hair on scalp and eyebrows at birth. On physical examination, scaly patches were observed on the whole body and spiky follicular hyperkeratotic papules were observed on the face and trunk. He also suffered from severe photophobia. Histopathological examination of the scalp showed miniaturized hair follicles without perifollicular fibrosis. Genetic analysis revealed a novel mutation in the MBTPS2 gene which was a homozygous missense mutation of c.245T>C leading to an amino-acid substitution from phenylalanine to serine (p.Phe82Ser). We diagnosed this patient with IFAP syndrome. To date, 25 pathogenic MBTPS2 gene mutations have been identified. To our knowledge, c.245T>C is a novel homozygous missense mutation in the MBTPS2 gene, which has not been reported in Human Gene Mutation Database, ClinVar Database, and Leiden Open Variation Database. Previous reports suggested genotype-phenotype correlations in the MBTPS2 gene mutations. Supported by a previous notion that genotype correlates with phenotype, this novel mutation can be a predictive factor for the mild form of IFAP syndrome, restricted to the classic symptom triad.

Onychophagia: detailed clinical characteristics.

BACKGROUND: Onychophagia is a common disorder affecting 20% to 30% of the general population. It is defined as habitual nail biting and can cause various changes in the nail units. However, to date, there has been a paucity of data focusing on nail deformities related to onychophagia. This study was performed to investigate the clinical characteristics of onychophagia in Korea. METHODS: This study included 53 patients with onychophagia who visited the Pusan National University Hospital (Busan and Yangsan) over a 10-year period (2011-2020). We retrospectively reviewed medical records and clinical and dermoscopic photographs. RESULTS: All 10 fingernails were affected in 37.7% of the patients. The left thumbnail was the most predominantly affected site (81.1%). Clinical findings showed that short nails with ragged distal borders were the most common presentation (100.0%), followed by generalized or patchy rough areas (50.9%), linear and pinpoint hemorrhage (32.1%), longitudinal melanonychia (30.2%), transverse groove (28.3%), brittleness (28.3%), macrolunula (24.5%), washboard nail (13.2%), and pterygium (3.8%). Of the patients, 88.7% had periungual complications, such as periungual exfoliation (77.4%), absent or ragged cuticle (52.8%), hyponychial hyperkeratosis (37.7%), and paronychia (15.1%). CONCLUSIONS: Although onychophagia is a common disorder, its clinical characteristics have not been reported in the literature. The results of this study may be helpful in managing patients with onychophagia.

Benign Umbilical Tumors Resembling Sister Mary Joseph Nodule.

BACKGROUND: When physicians see an umbilical nodule, most of them instinctively recall the Sister Mary Joseph nodule. Therefore, dermatologists need to recognize umbilical dermatoses that can be mistaken for the Sister Mary Joseph nodules. This study aimed to describe the different kinds of benign umbilical tumors as well as elucidate the factors that can be used to distinguish the Sister Mary Joseph nodule from these tumors. METHODS: The "benign umbilical tumor" group included 19 patients, whereas the "Sister Mary Joseph nodule" group comprised 30 patients (2 from our department, 28 from PubMed search). We compared the clinical and dermoscopic findings between 2 groups. RESULTS: In the "benign umbilical tumor" group, the most common diagnosis was dermatofibroma (5/19), followed by keloid (3/19), and soft fibroma (3/19). These tumors had various colors (red, brown to black, and flesh colored) and exhibit characteristic surface changes (eg, verrucous changes in epidermal nevi and verrucae). Conversely, most Sister Mary Joseph nodules have an erythematous color, oozing or ulceration on the surface, and nearby satellite lesions. Furthermore, the dermoscopic findings of Sister Mary Joseph nodules showed a polymorphous vascular pattern and a white or milky-red, amorphous area. Benign lesions showed different dermoscopic patterns: pigment networks with white areas (dermatofibromas), thrombosed capillaries (verrucae), and the "pore sign" (epidermal cysts). CONCLUSIONS: Various cutaneous tumors can be mistaken for the Sister Mary Joseph nodule when they develop on the umbilicus; the clinical and dermoscopic differences found in this study may be useful for establishing a differential diagnosis.