Lupus peritonitis presented as vague abdominal complaints in a SLE patient.

A 40-yr-old Caucasian woman who had been suffering from systemic lupus erythematosus (SLE) since five years developed vague abdominal complaints whilst under treatment with a low dose of steroids. She had been admitted because of vomiting and abdominal tenderness. The ESR and CRP levels were rising and the C4 level had been persistently low in the preceding months. Normal non-invasive procedures did not allow a diagnosis to be made. Therefore exploratory laparotomy was performed and revealed a non-bacterial peritonitis and an oedematous jejunum. She responded well to a high dose of prednisone. Serositis of the peritoneum as well as bowel vasculitis may be a rare manifestation of SLE despite apparent control of other lupus manifestations. In this patient serositis flares were associated with a rise in CRP level.