Cutaneous manifestations of gastrointestinal disease

The gastrointestinal (GI) and cutaneous organ systems are closely linked. In part I of this continuing medical education article, the intricacies of this relationship were explored as they pertained to hereditary polyposis disorders, hamartomatous disorders, and paraneoplastic disease. Part II focuses on the cutaneous system's links to inflammatory bowel disease and vascular disorders. An in-depth analysis of inflammatory bowel disease skin findings is provided to aid dermatologists in recognizing and facilitating early consultation and intervention by gastroenterologists. Cutaneous signs of inflammatory bowel disease include fissures and fistulae, erythema nodosum, pyoderma gangrenosum, pyostomatitis vegetans, oral aphthous ulcers, cutaneous polyarteritis nodosa, necrotizing vasculitis, and epidermolysis bullosa acquisita. Additional immune-mediated conditions, such as diverticulitis, bowel-associated dermatosis-arthritis syndrome, Henoch–Schönlein purpura, dermatitis herpetiformis, and Degos disease, in which the skin and GI system are mutually involved, will also be discussed. Genodermatoses common to both the GI tract and the skin include Hermansky–Pudlak syndrome, pseudoxanthoma elasticum, Ehlers–Danlos syndrome, hereditary hemorrhagic telangiectasia, and blue rubber bleb nevus syndrome. Kaposi sarcoma is a neoplastic disease with lesions involving both the skin and the gastrointestinal tract. Acrodermatitis enteropathica, a condition of zinc deficiency, likewise affects both the GI and dermatologic systems. These conditions are reviewed with updates on the genetic basis, diagnostic and screening modalities, and therapeutic options. Finally, GI complications associated with vascular disorders will also be discussed.