• Skin and Gut Microbiota in Psoriasis: A Narrative Review of Their Interconnected Roles in Disease Progression
  • Mohammad Amin Saghi,1,* Saba Soradi Mahkan,2 Ghazaleh Esfandiari,3
    1. Department of Biology, Faculty of Basic Sciences, Islamic Azad University, Mashhad, Iran
    2. Department of Biology, Faculty of Basic Sciences, Islamic Azad University, Mashhad, Iran
    3. Department of Biology, Faculty of Basic Sciences, Islamic Azad University, Mashhad, Iran


  • Introduction: The skin offers an immunological and physical barrier to the outer environment and harbors a sophisticated microbiota with a variety of microbial organisms. Disruption of this equilibrium can lead to dysbiosis and is a significant variable in the etiology of skin disorders. For the majority of instances, the microbiome plays a significant role in maintaining human health, homeostasis, immune status, and disease pathogenesis.A number of studies have shown that changes in the normal skin flora, and particularly the gut flora, can have negative implications for human health and result in disease development. The human host's gut harbors diverse microbial communities that have a close relationship with skin health and help sustain gut–skin balance. Interference with this interaction can lead to alterations in the immune system and ultimately the onset of skin diseases, but the exact mechanisms of this interaction are not fully understood. Among the dermatosis, psoriasis is one of the most common and chronic inflammatory disease which places a substantial burden on the quality of life of patients. Pathogenesis of psoriasis is multifactorial and involves several factors such as hereditary susceptibility, environmental factors such as smoking, alcohol, stress, some drugs, trauma, and immune system dysfunction. It is proposed by research that microbial imbalance of the skin is the primary factor which is accountable for the onset and exacerbation of psoriasis. Given the role of gut and skin microbiome-immune system interaction in disease pathogenesis, study of this interaction in psoriasis can provide greater insight into mechanisms of disease and lead to the development of novel therapeutic strategies. The aim of this article is to review current evidence on the role of microbiota (gut and skin) in psoriasis.
  • Methods: To prepare this review, we performed a thorough search of PubMed and Google Scholar. The main keywords were psoriasis, gut microbiota, skin microbiota, and microbiome. We focused on studies published from 2020 to 2025. Relevant research exploring changes in gut and skin microbiota in psoriasis—including reviews, clinical studies, and experimental work—were included, while studies that were irrelevant or lacked microbiota-related data were excluded.
  • Results: According to existing research, patterns of gut microbiome changes in psoriasis patients are congruent with those of individuals with inflammatory bowel disease. Both groups had diminished numbers of Faecalibacterium prausnitzii, Bifidobacterium spp., Lactobacillus, Parabacteroides, and Coprobacillus but higher levels of bacteria such as Salmonella, Campylobacter, Helicobacter, Escherichia coli, Alcaligenes, and Mycobacterium. Furthermore, the majority of research has shown quite differences in skin flora between patients with psoriasis and normal individuals. Worsening of psoriasis has been correlated with epidermal or mucosal colonization of microorganisms such as streptococci, Malassezia, Staphylococcus aureus, or Candida albicans. Findings from human and animal studies also support the therapeutic value of interventions that target the gut microbiota. These interventions include prebiotics, probiotics, dietary changes, and fecal microbiota transplantation (FMT), each with encouraging but inconsistent effects on reducing disease severity and systemic inflammation.
  • Conclusion: A review of the data indicates that both gut and skin microbiomes play a key role in the development and progression of psoriasis. Dysbiosis of both microbial communities is characterized by a reduction in regular bacteria and an increase in pathogenic organisms, changes that can be pro-immune and pro-inflammatory and allow for disease exacerbation. The close relationship of the gut–skin axis also means that modifications of the gut microbiome community can influence skin health in direct ways. On the other hand, observations from human and animal studies suggest that microbiome-targeted therapies such as probiotics, prebiotics, dietary intervention, and fecal microbiota transplantation may be novel therapeutic approaches, although existing evidence is neither rich nor even contradictory at times. In summary, a greater insight into microbiota–immune system interactions may provide new avenues towards the realization of personalized therapies in psoriasis treatment.
  • Keywords: Gut Microbiota, Skin Microbiota, Psoriasis