This report describes the case of a 44-year-old Caucasian woman of Northern European descent with a medical history of pyoderma gangrenosum, chronic abdominal pain and erythema nodosum which required intermittent use of high-dose steroids that failed to improve her symptoms. The patient was initially diagnosed with Crohn's disease and most recently with sclerosing mesenteritis. She presented to the hospital with worsening abdominal pain. She was found to have recurrent painful aphthous oral, genital and perianal ulcers and a clinical diagnosis of Behçet's disease was made. Her hospitalisation was complicated by haemoptysis, and bronchoscopy revealed alveolar haemorrhage. Treatment was initiated with three days of pulse intravenous solumedrol 1 g/day and cyclophosphamide at 700 mg/m(2). The case had a favourable outcome despite the initial diagnostic challenges. This report emphasises that systemic diseases, including Behçet's disease, can have variable presentations and can be frequently misdiagnosed.