Gut microbiome, metabolome and alopecia areata

Alopecia Areata: Understanding the Pathophysiology and Advancements in Treatment Modalities

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.

The Role of the Gut Microbiome and Microbial Dysbiosis in Common Skin Diseases

Dermatoses are an increasingly common problem, particularly in developed countries. The causes of this phenomenon include genetic factors and environmental elements. More and more scientific reports suggest that the gut microbiome, more specifically its dysbiosis, also plays an important role in the induction and progression of diseases, including dermatological diseases. The gut microbiome is recognised as the largest endocrine organ, and has a key function in maintaining human homeostasis. In this review, the authors will take a close look at the link between the gut-skin axis and the pathogenesis of dermatoses such as atopic dermatitis, psoriasis, alopecia areata, and acne. The authors will also focus on the role of probiotics in remodelling the microbiome and the alleviation of dermatoses.