Human skin and hair follicles are recognized sites of microbial colonization. These microbiota help regulate host immune mechanisms via an interplay between microbes and immune cells, influencing homeostasis and inflammation. Bacteria affect immune responses by controlling the local inflammatory milieu, the breakdown of which can result in chronic inflammatory disorders. Follicular microbiome shifts described in some inflammatory cutaneous diseases suggest a link between their development or perpetuation and dysbiosis. Though the hair follicle infundibulum is an area of intense immunological interactions, bulb and bulge regions represent immune-privileged niches. Immune privilege maintenance seems essential for hair growth and regeneration, as collapse and inflammation characterize inflammatory hair disorders like alopecia areata and primary cicatricial alopecia. Current research largely focuses on immunological aberrations. However, studies suggest that external stimuli and interactions across the follicular epithelium can have profound effects on the local immune system, homeostasis, and cycling. Herein, we review hair follicle bacterial colonization, its possible effects on the underlying tissue, and links to the pathogenesis of alopecia, beyond the pure investigation of specific species abundance. As skin microbiology enters the metagenomics era, multi-dimensional approaches will enable a new level of investigations on the effects of microorganisms and metabolism on host tissue.

The stomach contents of 104 individuals of Torquigener flavimaculosus from Cyprus were examined. The analysis revealed that it is an omnivorous species with a preference to animal prey, especially invertebrates with limited mobility (crustaceans, mo...

Despite their distinct clinical manifestation, frontal fibrosing alopecia (FFA) and lichen planopilaris (LPP) display similar histopathologic features. Aberrant innate immune responses to endogenous or exogenous triggers have been discussed as factors that could drive inflammatory cascades and the collapse of the stem cell niche. In this exploratory study, we investigate the bacterial composition of scalp skin and plucked hair follicles (HF) of patients with FFA, LPP and alopecia areata circumscripta (AAc), as well as healthy individuals, in relation to cellular infiltrates and the expression of defense mediators. The most abundant genus in lesional and non-lesional HFs of LPP and FFA patients was Staphylococcus, while Lawsonella dominated in healthy individuals and in AAc patients. We observed statistically significant differences in the ratio of Firmicutes to Actinobacteria between healthy scalp, lesional, and non-lesional sites of FFA and LPP patients. This marked dysbiosis in FFA and LPP in compartments close to the bulge was associated with increased HβD1 and HβD2 expression along the HFs from lesional sites, while IL-17A was increased in lesional HF from AAc patients. The data encourage further studies on how exogenous factors and molecular interactions across the HF epithelium could contribute to disease onset and propagation.

Background: Alopecia areata (AA) is a chronic immune-mediated condition leading to nonscarring hair loss. Its visible nature often leads to stigmatization and bullying, which can negatively affect the mental health and quality of life (QoL) of adolescents. Objectives: To investigate the experiences of bullying, psychosocial challenges and QoL in adolescents with AA. Methods: This cross-sectional study included 417 participants aged between 10 and 17 years, with 156 adolescents diagnosed with AA from 6 European countries and 261 healthy German controls. Data collection involved validated questionnaires. These included the Revised Olweus Bully/Victim Questionnaire for bullying, the Strengths and Difficulties Questionnaire for psychosocial difficulties, and the Pediatric Quality of Life Inventory for QoL. Clinical data, including AA severity score, were also recorded. Statistical analyses employed parametric and nonparametric methods, including multivariate analysis of variance, Mann–Whitney U-tests, t-tests and correlation analyses. Results: Adolescents with AA reported significantly higher rates of general and verbal bullying, with hair loss and nail damage commonly identified as reasons for bullying. Girls experienced more emotional distress and bullying, while boys reported better emotional and social QoL. Physical functioning (i.e. limitations in physical activity, pain or low energy) was significantly lower in the AA group, although overall QoL differences were low. Longer disease duration was associated with greater emotional difficulties and reduced school functioning. No association was found with the age of the participant or the severity of the disease. Conclusions: Adolescents with AA often face significant challenges, including higher rates of bullying and emotional struggles compared with healthy controls. Developing targeted interventions to combat stigma and support mental and emotional wellbeing of paediatric patients with AA, in addition to a collaborative effort involving dermatologists, psychologists and educators could possibly make a meaningful difference in improving the QoL for these young individuals.

Zusammenfassung: In diesem zweiten Teil der S3‐Leitlinie zur Diagnostik und Therapie der Alopecia areata (AA) stellen wir die zentralen Inhalte und Empfehlungen zur topischen und systemischen Therapie, zur Lebensqualität und zu Unterstützungsangeboten vor. Der separat publizierte erste Teil der Leitlinie umfasst die Definition der AA und Inhalte zur Epidemiologie, Diagnostik, Komorbidität, Risiko‐ und prognostischen Faktoren. Die Applikation von Kortikosteroiden ist die einzige Intervention mit hohem Empfehlungsgrad für topisch anzuwendende Wirkstoffe. Alle anderen topischen Wirkstoffe, die zur Therapie der AA eingesetzt werden, können angeboten werden, haben einen niedrigen Empfehlungsgrad, wobei die Empfehlungsgrade für die einzelnen topischen Wirkstoffe in den Altersgruppen Kinder, Jugendliche und Erwachsene variieren. Von den Wirkstoffen zur systemischen Therapie der AA haben nur die systemischen Kortikosteroide und die Januskinase‐Inhibitoren einen hohen Empfehlungsgrad, allerdings mit der Einschränkung, dass sich die Empfehlungen in der Anwendung nur auf Erwachsene beziehen. Kindern und Jugendlichen können Kortikosteroide, Methotrexat oder Januskinase‐Inhibitoren* (*bei entsprechender Zulassung für die Altersgruppe) ab einer schweren Form angeboten werden. Alle anderen systemischen Wirkstoffe sollten Kindern und Jugendlichen nicht angeboten werden. Die Leitliniengruppe empfiehlt, dass alle Patientinnen und Patienten mit allen Formen der AA, unabhängig vom Alter, über die Möglichkeiten eines Haarersatzes und über kosmetische Angebote informiert werden sollen.

Summary: Background and Objectives: Hair loss disorders impact quality of life (QoL) far beyond cosmetic issues, with previous studies showing mild to moderate impairment. This study aimed to assess QoL impairment in hair loss patients, comparing scarring and non‐scarring alopecia, and to analyze possibly related influencing factors. Patients and Methods: An exploratory cross‐sectional study of 510 patients (281 with non‐scarring and 229 with scarring alopecia) was conducted at the Charité –Universitätsmedizin Berlin's dermatology outpatient clinic. DLQI and PROMIS questionnaires were completed. T‐tests, three‐factor analysis of variance with post hoc tests, and correlation analyses were used for evaluation. Results: Hair loss disorders can lead to an impaired QoL, with psychological well‐being being the most affected. DLQI scores showed moderate impairment in both alopecia types. In addition, PROMIS indicated mild anxiety impairment in both, and mild depressive symptoms in non‐scarring alopecia. Subjects with non‐scarring type were more affected in their psychological well‐being than those with scarring alopecia. A greater impairment was partially observed at a younger age in both types of alopecia and in women with non‐scarring alopecia. Conclusions: This exploratory study suggests that hair loss may lead to a notable emotional burden; thus, psychological support could be considered beneficial in hair loss management.