Common causes of left upper abdominal pain include post-traumatic rupture of the spleen, splenic cyst, acute splenic torsion, acute pancreatitis, lobar pneumonia of the lower left lobe of the lung, and herpes zoster of the left abdominal wall. Some patients with acute and chronic gastritis, gastric ulcer, gastric perforation, gastric cancer, and intercostal neuritis may also present with left upper abdominal pain.