[Cutaneous involvement in chronic inflammatory bowel disease : Crohn's disease and ulcerative colitis]

Over recent decades, both the incidence and prevalence of chronic inflammatory bowel disease have continued to rise in industrialized countries; the disease is frequently associated with extracutaneous involvement and comorbidity.

The purpose of this work was to investigate the frequency and specificity of mucocutaneous manifestations in Crohn's disease (CD) and ulcerative colitis (UC).

An extensive search in peer-reviewed journals via PubMed was performed; presented is a summary and analysis of various studies and data, including data of patients treated at our department.

CD and UC are frequently associated with mucocutaneous symptoms; however, primary/specific disease-associations are exclusively seen in CD patients. These include peri-anal and -stomal fistulas and ulcerations, "metastatic" Crohn's disease as well as oral granulomatous disease. Moreover, in both CD and UC, there occur several other inflammatory skin conditions such as erythema nodosum, pyoderma gangrenosum, hidradenitis suppurativa, chronic oral aphthous disease, Sweet syndrome, pyostomatitis vegetans, and bowel-associated dermatosis-arthritis syndrome. Malnutrition syndromes (zinc and vitamin deficiencies) are only rarely observed.

On skin and oral/genital mucous membranes various different inflammatory manifestations may be observed during the course of CD or UC. However, most data about a direct pathogenic relationship of the gastrointestinal and dermatologic disorders are quite heterogeneous or even contradictory. Nevertheless, knowledge of these conditions and their possible association with CD and UC could be crucial for early diagnosis and initiation of an appropriate therapy and thus be essential to prevent secondary tissue damage.