Gastrointestinal symptom due to lupus peritonitis: a rare form of onset of SLE.

Serositis is commonly seen in systemic lupus erythematosus (SLE). Approximately 16% of patients with SLE have pleural or pericardial involvement. However, peritoneal involvement is extremely rare, and SLE with ascites as the first manifestation is an even rarer condition. This is the case report of a 19-year old male with discoid lupus who evolved with gastrointestinal symptoms as the first manifestation of the disease, characterized by significant abdominal distension and pain, asthenia, vomiting, and signs of ascites. An abdominal CT scan demonstrated ascites and marked edematous thickening of the bowel wall, which appeared as "target sign", and "double-track sign". Laboratory tests showed that his serum complement levels decreased and that he was positive for anti-nRNP/Sm antibodies, anti-Sm antibodies, anti-SS-A antibody, and anti-nuclear antibodies. The patient was treated with prednisone and chloroquine, with substantial improvement of his condition.