Abdominal pain with dengue fever can be a diagnostic challenge. Typically, pain is localised to the epigastric region or associated with hepatomegaly. Patients can also present with acute abdomen. We report a case of a girl with dengue fever and right iliac fossa pain. The diagnosis of acute appendicitis was made only after four days of admission. An appendicular mass and a perforated appendix was noted during appendectomy. The patient recovered subsequently. Features suggestive of acute appendicitis are persistent right iliac fossa pain, localised peritonism, persistent fever and leucocytosis. Repeated clinical assessment is important to avoid missing a concurrent diagnosis like acute appendicitis.