Alopecia areata: Mechanisms, targeted therapies, and translational challenges

Alopecia areata (AA) is an immune-mediated disorder characterized by non-scarring hair loss and substantial psychosocial burden. Although recent advances have clarified key pathogenic mechanisms and expanded therapeutic options, important uncertainties persist regarding disease heterogeneity, treatment durability, and long-term safety. Central to AA pathogenesis is the collapse of hair follicle immune privilege, driven primarily by cytotoxic CD8⁺ NKG2D⁺ T-cells and sustained by interferon-γ-dependent Janus kinase-signal transducer and activator of transcription (JAK-STAT) signaling. However, emerging evidence indicates immunological variability across patient subsets, including inconsistent contributions from T helper cell pathways and regulatory immune dysfunction. The clinical approval of JAK inhibitors-baricitinib, ritlecitinib, and deuruxolitinib-represents a major therapeutic milestone, validating targeted immune modulation as an effective strategy for moderate-to-severe AA. Nevertheless, relapse following treatment discontinuation, interindividual variability in response, and unresolved long-term safety considerations highlight the limitations of current approaches. In parallel, regenerative therapies, microbiome-based interventions, gene-targeted strategies, and device-assisted technologies are under investigation, yet most face substantial translational, regulatory, and scalability challenges. This review critically synthesizes current evidence on AA pathogenesis and therapy, with particular emphasis on unresolved controversies, translational barriers, and clinical implications. By integrating mechanistic insights with emerging clinical data, the article highlights priorities for future research, including biomarker development, precision medicine approaches, and strategies aimed at achieving durable disease control rather than transient immune suppression.