Review article: skin complications associated with inflammatory bowel disease.
Cutaneous manifestations are well-recognized complications of Crohn's disease and ulcerative colitis. The incidence of these manifestations varies widely but, at the time of diagnosis, the mean incidence is around 10%. During the course of the disease, a great variety of skin lesions may develop, many of which are secondary to granulomatous cutaneous disease, reactive skin eruptions, nutritional deficiency and other associated conditions. The disorders that are directly related to the inflammatory process of Crohn's disease include perianal and peristomal ulcers and fistulae, metastatic Crohn's disease and oral granulomatous lesions. Histologically, the features are similar to those found in the inflamed bowel. These lesions usually respond to treatment of the underlying intestinal disease. The most common forms of reactive skin eruption are erythema nodosum and pyoderma gangrenosum. Certain subsets of patients are more susceptible to the development of erythema nodosum; in a previous report from our group, erythema nodosum was seen mainly in females, and in patients with colonic involvement and/or arthritis. This manifestation tends to occur during the first 2 years of the clinical course of the disease and may recur in approximately one-half of cases. Infliximab is highly effective in healing refractory lesions of erythema nodosum and pyoderma gangrenosum. Manifestations that are secondary to nutritional deficiency or associated conditions include acrodermatitis enteropathica, psoriasis and autoimmune disorders. For most of the cutaneous manifestations, the primary therapeutic target remains the bowel. Early aggressive therapy can minimize severe complications and maintenance treatment may prevent some devastating consequences.