Alopecia Areata: Understanding the Pathophysiology and Advancements in Treatment Modalities

Abstract

Alopecia areata (AA) is an autoimmune condition that presents with non-scarring hair loss affecting multiple patients worldwide during their lifetime. It ranges from well-defined patchy to diffuse total hair loss, impacting all hair-bearing areas of the body. AA most commonly predominantly manifests on the scalp. The pathophysiology of AA is complex and multi-faceted. The findings of our review article were consistent with the recent literature, delineating autoimmunity, genetic susceptibility, and environmental aspects to be the contributing factors. One of the main causes of AA is believed to be the disruption in the immune privilege of the hair follicles. Multiple genetic loci involved in hair follicle maturation and immune process have been linked to the development of AA as evidenced by several studies. It has been postulated that psychological stressors, smoking, alcohol consumption, sleep disturbances, gut microbiota, and drugs play a role in the pathogenesis of AA by exacerbating the immune response against the hair follicles. AA is a clinically diagnosed disorder. Topical, intra-lesional, and oral corticosteroids, topical and oral minoxidil, cyclosporine, and other immune therapy drugs are widely accepted first-line treatment options, although incomplete remission and relapses are common. Recently JAK-2 inhibitors and mesenchymal stem cell exosomes have shown promising results, potentially treating severe and refractory hair loss. AA has a bidirectional relationship with psychological symptoms as it can lead to social anxiety and depression, which in turn can aggravate hair loss. Hence, it is crucial to implement a holistic approach to managing AA including topical and systemic therapies, psychological counseling, and lifestyle modifications. It is imperative to fully declinate the pathophysiological mechanisms of the disease and formulate therapies in future research to help clinicians and dermatologists devise definitive guidelines to treat the condition for long-term remission.

Keywords: alopecia areata; hair follicles; hair loss; immune privilege loss; immunotherapy; intralesional corticosteroid; jak inhibitor; mesenchymal stem cell therapy; minoxidil.

Figure 1. Summary of factors that contribute to pathophysiology of alopecia areata

Figure made using biorender.com. Credit: Image created by the authors.