Crohn's disease: an important differential diagnosis of granulomatous skin diseases.

Metastatic Crohn's disease is a very rare skin manifestation of Crohn's disease. Its time of occurrence and severity do not necessarily correlate with the intestinal disease. The main characteristic is that the granulomatous skin changes occur at sites distant from the bowel. We report the case of a 65-year-old woman with metastatic Crohn's disease on her right lower leg without clinical intestinal signs at the time of diagnosis. The inflammatory pustulating skin lesions resolved after systemic and topical treatment with corticosteroids. After reducing immunosuppressive therapy, fistulating lesions reappeared on the lower legs and at the mons pubis. Coloscopy now, more than five years after the onset of the first skin lesions, showed an intestinal Crohn's disease. Metastatic Crohn's disease and its differential diagnoses with granulomatous reaction pattern are discussed in this manuscript.