Blood in the stool and anal itching are two completely different symptoms, each representing a different type of disease. 1. If it is a rectal polyp, it is also painless blood in the stool and requires proctoscopy to confirm the diagnosis. 4. Itchy anus is often a sign of anal pruritus or external hemorrhoids. If it is anal pruritus, the itch is more pronounced at night, and if it is caused by external hemorrhoids, the itch does not distinguish between day and night.