Painless Rectal Bleeding: Causes from Hemorrhoids to Cancer

Painless rectal bleeding (hematochezia) is never normal. Even without constipation, it requires evaluation.

Common Causes (Benign to Malignant)

1. Internal hemorrhoids (Grades I–IV): Bright red blood on paper/in bowl; prolapse may reduce spontaneously. Most common cause.
2. Anal fissure: Usually painful, but can be painless if chronic/superficial.
3. Diverticular bleeding: Painless, maroon/bright red, large volume. Common >60 yrs. Self-limited 80% but recurs.
4. Inflammatory bowel disease: Ulcerative colitis (blood + mucus, urgency), Crohn's (variable). Often with diarrhea/pain.
5. Angiodysplasia: Vascular malformations; elderly; recurrent, painless.
6. Colorectal polyps / adenocarcinoma: Painless bleeding often only early sign. Right-sided: maroon/occult; left-sided/rectal: bright red.
7. Radiation proctitis: Post-pelvic RT; telangiectasias bleed.
8. Solitary rectal ulcer syndrome: Straining, prolapse; bleeding, mucus.

Red Flags for Urgent Evaluation

• Age ≥45 (or ≥40 with risk factors)
• Family history CRC/polyps
• Weight loss, anemia (fatigue, pallor)
• Change in stool caliber, tenesmus
• Bleeding + anticoagulants (still investigate)

Diagnostic Pathway

• Digital rectal exam, anoscopy
• Colonoscopy (gold standard: visualize, biopsy, polypectomy)
• CT colonography if incomplete colonoscopy
• Capsule endoscopy for small bowel

Don't assume "just hemorrhoids." Early CRC detection = 90% 5-yr survival. Get scoped per guidelines (45 average risk).