Comorbidity of inflammatory bowel diseases and psoriasis

Inflammatory bowel diseases, which include Crohn's disease and ulcerative colitis, are a global disease of the 21st century. Psoriasis affects about 125 million people worldwide, it is one of the most common skin diseases and occurs in 2–3 % of the population of countries. Psoriasis, psoriatic arthritis are extraintestinal (systemic) manifestations of IBD, not associated with the activity of ulcerative colitis and Crohn's disease. At the same time, the epidemiology of the relationship between IBD and psoriasis has not been sufficiently studied. We searched the Pubmed and Scopus databases for articles published before 01/25/2025 that examined the relationship between IBD and psoriasis. The results of epidemiological and clinical studies, their generalizations in systematic reviews and meta-analyses, indicate the presence of a bidirectional relationship between IBD and psoriasis. The mechanisms of the relationship include similar pathophysiological processes, including comparable immunopathogenic mechanisms (primarily the involvement of Th17, IL-17, IL-23 and TNF-α), common inflammatory pathways, common susceptibility loci and DNA polymorphism at the genetic level, dysbiosis of the intestinal microbiome, intestinal permeability disorders, which play a key role in the development of IBD and psoriasis. In patients with psoriasis, consultation with a gastroenterologist is indicated in the presence of intestinal symptoms. When curating patients with IBD and psoriasis, interaction and close cooperation between a gastroenterologist and a dermatologist is advisable.