Abdominal pain continues to pose diagnostic challenges for emergency clinicians. A 56-year-old Japanese woman was referred to our hospital due to severe abdominal pain which presented as occasional epigastric pain five months before and intermittent abdominal pain. She had a past history of ileus twice, for both of which laparotomy was performed without an alimentary tract resection. The wall thickening with marked three-wall structure from terminal ileum to sigmoid colon was seen and bladder wall was irregularly thick and enhanced irregularly. Among the differential diagnosis of the acute abdomen, autoimmune diseases were suspected, especially lupus erythematosus and Henoch-Schönlein purpura. On the second day of admission, abdominal pain worsened. The results of examinations of antinuclear antibody, anti-double-stranded DNA antibody, ANCA, and the complements were not obtained at that time; however, we started 1-g steroid pulse treatment for three days with success. With the results obtained later, the patient was given a diagnosis of probable systemic lupus erythematosus (SLE). The present case shows that SLE can present with acute abdomen and should be included in the wide range of the differential diagnosis of acute abdomen.