Porokeratosis and Crohn's disease.

We report the cases of three patients with Crohn's disease in whom porokeratosis developed. Disseminated superficial actinic porokeratosis developed in two patients. In one of these patients, the skin lesions arose during an exacerbation of the bowel disease. In the third patient, who had congenital linear porokeratosis, the disseminated superficial form of the disorder developed during the first severe exacerbation of Crohn's disease. A family history of porokeratosis was present in one patient, but no relatives of any of these patients were known to have Crohn's disease. In all three patients, Crohn's disease was limited to the colon.