Psoriasis and inflammatory bowel disease: links and risks

Abstract

Psoriasis and the spectrum of inflammatory bowel diseases (IBD) are chronic, inflammatory, organotropic conditions. The epidemiologic coexistence of these diseases is corroborated by findings at the level of disease, biogeography, and intrafamilial and intrapatient coincidence. The identification of shared susceptibility loci and DNA polymorphisms has confirmed this correlation at a genetic level. The pathogenesis of both diseases implicates the innate and adaptive segments of the immune system. Increased permeability of the epidermal barrier in skin and intestine underlies the augmented interaction of allergens and pathogens with inflammatory receptors of immune cells. The immune response between psoriasis and IBD is similar and comprises phagocytic, dendritic, and natural killer cell, along with a milieu of cytokines and antimicrobial peptides that stimulate T-cells. The interplay between dendritic cells and Th17 cells appears to be the core dysregulated immune pathway in all these conditions. The distinct similarities in the pathogenesis are also reflected in the wide overlapping of their therapeutic approaches. Small-molecule pharmacologic immunomodulators have been applied, and more recently, biologic treatments that target proinflammatory interleukins have been introduced or are currently being evaluated. However, the fact that some treatments are quite selective for either skin or gut conditions also highlights their crucial pathophysiologic differences. In the present review, a comprehensive comparison of risk factors, pathogenesis links, and therapeutic strategies for psoriasis and IBD is presented. Specific emphasis is placed on the role of the immune cell species and inflammatory mediators participating in the pathogenesis of these diseases.

Crohn’s disease exacerbated by IL-17 inhibitors in patients with psoriasis: a case report

“…Previous studies revealed that psoriasis and IBD have highly overlapping epidemiological characteristics, genetic susceptibility loci, disease risk factors, immune mechanisms, and comorbidities. IBD patients and psoriasis patients have increased probability of suffering from the other disease [ 1 , 2 ]. Although some clinical cases about the use of interleukin (IL)-17 blockers inducing CD have been reported, the patient had suffered from psoriasis and CD before the use of IL-17 inhibitor is quite rare.…”

Crucial Role of Microbiota in Experimental Psoriasis Revealed by a Gnotobiotic Mouse Model

“…Based on our studies, colonization of the gastrointestinal tract of germ-free (GF) animals with one bacterial strain or complex intestinal microbiota influences the host immune system at the local and systemic level, promoting proinflammatory or anti-inflammatory response, depending on the species used (Tlaskalova-Hogenova et al., 2011). The importance of the gut-skin axis in pathogenesis of psoriasis has been recently documented in humans as well as in animal models of psoriasis (Fry et al., 2013; Zanvit et al., 2015; Vlachos et al., 2016; Zakostelska et al., 2016; Drago et al., 2018). Recovery from intestinal dysbiosis, e.g., by healing the syndrome of small intestinal bacterial overgrowth, may mitigate the symptoms of psoriatic patients (Drago et al., 2018).…”

Asymptomatic Crohn’s disease identified in a patient being treated with secukinumab: A case report

“…The anatomical and functional integrity of the tissue environment barriers is compromised in the skin of psoriasis patients and intestinal lumen of IBD patients. 3 Psoriasis and IBD are linked epidemiologically as well as genetically. In a population-based nationwide study in Korea, psoriasis patients had a higher risk of IBD than did the general population.…”