Hair loss, though often dismissed as cosmetic, reflects complex vascular, metabolic, structural, and inflammatory changes within the scalp microenvironment. Conventional diagnostic tools such as visual inspection, dermoscopy, trichoscopy, and biopsy remain limited in their ability to determine these evolving processes non-invasively. Recent advances in optical physics and biomedical engineering have introduced light- and wave-based imaging approaches that may expand scalp diagnostics beyond surface visualization. Hyperspectral imaging (HSI) and terahertz (THz) imaging have demonstrated comparable capabilities for assessing tissue biochemistry, microstructure, hydration dynamics, pigmentation, and vascular signatures in related dermatologic applications and may support exploratory investigation of scalp assessment after validation. However, direct clinical evidence supporting HSI and THz imaging specifically in hair-loss patients remains limited. Therefore, this review integrates available alopecia-related imaging evidence, mechanistic and modeling evidence relevant to hair biology, and extrapolated findings from broader dermatologic applications, including oncology and wound-healing research. Relevant literature was identified by structured searches of PubMed, Scopus, and Google Scholar, covering studies published from June 2008 to March 2026. The review analyzes how these technologies may identify indirect, non-invasive scalp-tissue indicators associated with follicular miniaturization, perifollicular inflammation, fibrosis, vascular compromise, hydration imbalance, and treatment response. By merging spectral and wave-derived data with AI-based analytics and quantitative biomarkers, HSI and THz imaging may, upon validation, contribute to a shift from subjective grading to dynamic exploratory physiological mapping of superficial scalp tissue. Nevertheless, clinical translation will require scalp-specific validation, standardized acquisition protocols, normative datasets among different hair types, and correlation with established trichoscopic, histological, and clinical endpoints. Overall, these technologies constitute promising but investigational frontiers in precision alopecia diagnostics and data-guided hair-loss management.

Allergen immunotherapy (AIT) is the only disease-modifying treatment for IgE-mediated allergic disorders, including allergic rhinitis and asthma, with established long-term clinical efficacy and immunological tolerance induction.

Atopic dermatitis (AD) is a chronic, relapsing inflammatory skin disorder characterized by intense pruritus, eczematous lesions, and significant impairment of quality of life. In severe or chronic cases, AD can present with diverse atypical phenotypes, among which prurigo nodularis (PN)-like lesions are clinically challenging due to their recalcitrance to conventional therapies. Patients with severe AD are also at an increased risk of comorbid immune-mediated diseases, such as alopecia areata (AA), a non-scarring hair loss disorder driven by aberrant immune responses. Ivarmacitinib, a highly selective oral Janus kinase 1 (JAK1) inhibitor, has been approved by the National Medical Products Administration (NMPA) of China for moderate-to-severe atopic dermatitis (April 2025) and alopecia areata (June 2025). Herein, we report a case of a 28-year-old male patient with a long-standing history of AD who developed generalized PN-like lesions and concurrent AA (with a 2-year disease duration) and androgenetic alopecia (AGA). Conventional therapies including topical corticosteroids and antihistamines failed to yield satisfactory outcomes. Following treatment with ivarmacitinib (8 mg once daily), the patient showed rapid improvements in skin lesions, pruritus, and hair regrowth. This case suggests that ivarmacitinib may be beneficial for complex AD phenotypes with comorbid immune-mediated hair loss.

Introduction Alopecia areata (AA) is an autoimmune, non-scarring hair loss disorder increasingly recognized as a systemic immune-mediated condition. Previous studies examining AA-associated autoimmune diseases were limited by narrow disease scope, single-country cohorts, or lack of bidirectional and sex-stratified analyses. This study comprehensively evaluated over 50 autoimmune conditions in AA patients, performed bidirectional analyses exploring temporal relationships, and conducted sex-stratified assessments to identify gender-specific risk. Methods We conducted a retrospective cohort study using the TriNetX Global Health Research Network, incorporating de-identified electronic health records from over 120 million patients worldwide. Adults with AA were 1:1 propensity score-matched with controls (n=69,259) based on demographics and comorbidities. Over 50 autoimmune and inflammatory disorders were assessed using Cox proportional hazards models. Reverse analyses and sex-stratified cohorts were performed. Sensitivity analyses tested robustness through temporal restrictions, recent data periods, and stricter diagnostic criteria. Results AA was strongly associated with endocrine, rheumatologic, dermatologic, gastrointestinal, hepatic, neurologic, and systemic autoimmune diseases. Highest hazard ratios included cutaneous lupus erythematosus (HR=9.843), systemic lupus erythematosus (HR=5.807), vitiligo (HR=3.844), lichen planus (HR=3.627), and Addison's disease (HR=3.847). Reverse analyses demonstrated that lichen planus (HR=6.205), cutaneous lupus erythematosus (HR=5.579), and vitiligo (HR=4.505) markedly increased AA risk. Females with AA had higher risks of thyroid, rheumatologic, and cutaneous autoimmune disorders, while males showed higher vitiligo risk. Conclusions AA was associated with increased risk of multiple autoimmune and inflammatory diseases in both directions. These findings support considering AA as a clinically visible marker of increased autoimmune susceptibility and may justify targeted evaluation for thyroid and connective tissue disorders, particularly in females with AA, as well as clinical awareness of AA risk in patients with autoimmune skin diseases.