Recent research in Sweden highlights a connection between psoriasis, a chronic hereditary skin condition, and inflammation in the small intestine. The study, published in Biochimica et Biophysica Acta (BBA)-Molecular Basis of Disease, reveals that psoriasis sufferers often experience invisible inflammation in the small intestine, which increases the likelihood of a “leaky gut.” This finding could explain the prevalence of gastrointestinal problems and the risk of Crohn’s disease among individuals with psoriasis.
Psoriasis affects nearly 300,000 people in Sweden and is marked by both skin symptoms and, in some cases, joint inflammation. Chronic inflammatory bowel diseases (IBD), particularly Crohn’s disease, are more frequently observed in psoriasis patients compared to the general population. Previous studies have reported a higher incidence of gastrointestinal issues in individuals with psoriasis. However, the mechanisms behind this relationship were not well understood until now. Fu et al. conducted a meta-analysis showing a significant association between psoriasis and Crohn’s disease, emphasizing the need for greater awareness of gastrointestinal comorbidities in these patients. Thye et.al, in their study have demonstrated that individuals with psoriasis often exhibit an imbalance in their gut microbiota, characterized by a decreased abundance of Bacteroidota and an increased presence of Firmicutes. This dysbiosis is believed to contribute to the inflammatory processes observed in psoriasis.
The study included 18 psoriasis patients and 15 healthy participants, none of whom had been diagnosed with gastrointestinal diseases. Researchers collected samples from both the small and large intestines, analyzing the types and activity of immune cells in the mucous membranes. The results indicated a significant presence of certain immune cells in the small intestine of psoriasis patients, which exhibited pro-inflammatory activity. Interestingly, these same immune cells are commonly found in psoriasis-related skin flare-ups, suggesting a possible link between skin and gut inflammation. Salem et al. demonstrated that the gut-skin axis plays a crucial role in the inflammatory processes observed in psoriasis.
The intestinal mucosa, which normally acts as a protective barrier, allows for the passage of nutrients and water while preventing harmful substances from entering the bloodstream. In some autoimmune conditions, including psoriasis, this barrier may function inadequately, leading to increased intestinal permeability or “leaky gut.” This condition allows bacteria and other harmful substances to cross the intestinal barrier, triggering inflammation. These substances can then circulate through the bloodstream, potentially causing more widespread inflammation in the body.
Half of the psoriasis patients in the study exhibited signs of leaky gut and reported more frequent gastrointestinal symptoms, such as abdominal pain and bloating, compared to those with a normal intestinal barrier. These patients also showed higher levels of inflammatory markers in their intestines, despite having relatively mild skin disease and no visible signs of intestinal inflammation during gastroscopy. The findings underline the subtle yet impactful changes occurring in the small intestines of psoriasis patients.
Francesco and Caruso stated that both psoriasis and IBD involve dysregulated immune responses, particularly the overactivity of T helper 17 (Th17) cells. This shared immunological mechanism suggests a common pathway contributing to inflammation in both the skin and the gut.
This study highlights the common occurrence of gastrointestinal problems in individuals with psoriasis and their increased risk of developing Crohn’s disease, underscoring the interconnectedness of gut and skin inflammation. The findings are significant for improving the diagnosis, management, and treatment of psoriasis-associated gastrointestinal problems, paving the way for targeted therapies that address both conditions and enhance patients’ quality of life. By identifying the underlying mechanisms linking these systems, the research advocates for a holistic approach to managing chronic conditions like psoriasis.
References
- Lundquist P, Hagforsen E, Wagner M, Alimohammadi M, Melo FR, Pejler G, et al. Mild-to-moderate psoriasis is associated with subclinical inflammation in the duodenum and a tendency of disturbed intestinal barrier. Biochimica et Biophysica Acta (BBA) – Molecular Basis of Disease. 2025 Mar 1;1871(3):167634.
- Fu Y, Lee CH, Chi CC. Association of Psoriasis With Inflammatory Bowel Disease: A Systematic Review and Meta-analysis. JAMA Dermatol. 2018 Dec 1;154(12):1417–23.
- Salem I, Ramser A, Isham N, Ghannoum MA. The Gut Microbiome as a Major Regulator of the Gut-Skin Axis. Front Microbiol. 2018 Jul 10;9:1459.
- Thye AYK, Bah YR, Law JWF, Tan LTH, He YW, Wong SH, et al. Gut–Skin Axis: Unravelling the Connection between the Gut Microbiome and Psoriasis. Biomedicines. 2022 Apr 30;10(5):1037.
- De Francesco MA, Caruso A. The Gut Microbiome in Psoriasis and Crohn’s Disease: Is Its Perturbation a Common Denominator for Their Pathogenesis? Vaccines (Basel). 2022 Feb 5;10(2):244.