| Common causes | Rare causes | |
| Under age 40 years | Over age 40 years | Henoch-Schoenlein purpura |
| Inflammatory bowel disease | NSAID ulcers | Small bowel varices and/or portal hypertensive enteropathy |
| Meckel diverticulum | Angioectasia | Amyloidosis |
| Dieulafoy lesions | Dieulafoy lesions | Blue rubber bleb nevus syndrome |
| Neoplasia | Neoplasia | Pseudoxanthoma elasticum |
| Polyposis syndromes | Hereditary hemorrhagic telangiectasia (Osler-Weber-Rendu syndrome) | |
| Kaposi sarcoma with AIDS | ||
| Plummer-Vinson syndrome | ||
| Ehlers-Danlos syndrome | ||
| Inherited polyposis syndromes (FAP, Peutz-Jeghers) | ||
| Malignant atrophic papulosis | ||
| Hematobilia | ||
| Aortoenteric fistula | ||
| Hemosuccus entericus | ||
