Angiodysplasia is another cause of acute lower GI haemorrhage and is an acquired malformation of intestinal blood vessels with ectatic vessels in the mucosa and submucosa. Dilated vessels or cherry red, flat lesions are seen at colonoscopy.

Angiodysplasia most commonly presents with iron deficiency anaemia and occult blood loss. This is due to slow but repeated episodes of bleeding (often found in asymptomatic individuals or as an incidental finding.

When overt bleeding from angiodysplasia occurs it is typically brisk, painless and intermittent.