Complications the sources name
Mayo Clinic says hemorrhoid complications are rare and names anemia from ongoing blood loss, a strangulated internal hemorrhoid, and a clot in an external hemorrhoid. Cleveland Clinic agrees on those three and adds infection and skin tags. NIDDK says to seek care right away for severe anal pain and rectal bleeding, particularly with abdominal pain, diarrhea, or fever.
By ahem. Published October 26, 2026.
Three findings Mayo Clinic names
These are complications named on public pages opened October 26, 2026. Matching a sentence does not mean that is the problem. ahem has not examined anyone.
Mayo Clinic dates its symptoms page August 23, 2025. On the copy checked October 26, 2026, it says complications of hemorrhoids are rare and may include three problems. Anemia can follow ongoing blood loss, rarely, when there are not enough healthy red blood cells to carry oxygen. A strangulated hemorrhoid is an internal hemorrhoid whose blood supply has been cut off, and it can cause extreme pain. A blood clot can form in a hemorrhoid. Mayo Clinic says that clot, also called a thrombosed hemorrhoid, is not dangerous, can be extremely painful, and sometimes needs to be drained.
The symptoms section of the same page describes the clot in an external hemorrhoid more closely: blood pools and forms a thrombus, which can bring severe pain, swelling, inflammation, and a hard, discolored lump near the anus. Internal hemorrhoids, on that page, are usually painless and tend to bleed. A prolapsed internal hemorrhoid may cause pain and irritation. Prolapse is in the symptom list. Strangulation is in the complication list.
What Cleveland Clinic adds
Cleveland Clinic updated its page on May 5, 2025. Opened October 26, 2026, it says hemorrhoids can be uncomfortable and painful and do not tend to cause serious problems. Rarely, people develop anemia, blood clots in external hemorrhoids, infection, skin tags, or strangulated hemorrhoids. Its strangulated line says muscles in the anus cut off blood flow to a prolapsed internal hemorrhoid. Mayo Clinic's line says the blood supply to an internal hemorrhoid is cut off. Both call the result strangulated. Cleveland Clinic adds infection and skin tags to the rare-complication list. Mayo Clinic's complication list does not.
Cleveland Clinic also describes a thrombosed external hemorrhoid as a purple or blue lump, and says the clot affects the anus and does not travel to other parts of the body. Mayo Clinic calls the lump hard and discolored and says the clot is not dangerous. The shared point is a painful clot in an external hemorrhoid. The color words are Cleveland Clinic's.
The clot, and the clock on removal
Mayo Clinic's treatment page, dated August 23, 2025 and checked October 26, 2026, says a clinician can remove a painful clot in an external hemorrhoid, which can relieve pain right away. The procedure uses a local anesthetic. Thrombectomy works best when done within 72 hours of the clot. That 72-hour figure is Mayo Clinic's treatment page.
NIDDK's treatment page, last reviewed in October 2016 and opened October 26, 2026, does not give 72 hours. How that clot sits next to the usual few days or week of hemorrhoid symptoms is on how long hemorrhoid symptoms usually last. Office procedures for bleeding or prolapsing internal hemorrhoids, which are a different problem from a clot under the skin, are on office treatments for hemorrhoids.
When the pages say to get care now
NIDDK's treatment page, checked October 26, 2026, says to seek medical care right away for severe anal pain and bleeding from the rectum, particularly with discomfort or pain in the abdomen, diarrhea, or fever. Cleveland Clinic says to call a clinician for abdominal pain, chronic constipation or diarrhea, fever and chills, nausea and vomiting, or severe rectal bleeding and pain. It also says other gastrointestinal disorders can cause rectal bleeding and symptoms that resemble hemorrhoids, and that some of those disorders are life-threatening.
Mayo Clinic, on the symptoms page checked October 26, 2026, says to seek emergency care for a large amount of rectal bleeding, or for lightheadedness, dizziness, or faintness. A strangulated hemorrhoid can cause extreme pain. A clot can be extremely painful and sometimes needs to be drained, and Mayo Clinic says that clot is not dangerous. Ongoing blood loss can rarely cause anemia.
- Large-amount bleeding, or bleeding with lightheadedness, dizziness, or faintness: Mayo Clinic says to seek emergency care.
- Severe anal pain and rectal bleeding, particularly with abdominal pain, diarrhea, or fever: NIDDK says to seek care right away.
- Severe rectal bleeding and pain, fever and chills, abdominal pain, or nausea and vomiting: Cleveland Clinic says to call a clinician.
- A painful external clot: Mayo Clinic says removal works best within 72 hours. That timing is on the treatment page, checked October 26, 2026.
The fuller bleeding check, including diseases other than hemorrhoids, is on when rectal bleeding should be checked.
Sources
- Hemorrhoids: Symptoms and causes. Mayo Clinic. Accessed October 26, 2026. Mayo Clinic dates this page August 23, 2025.
- Hemorrhoids: Diagnosis and treatment. Mayo Clinic. Accessed October 26, 2026. Mayo Clinic dates this page August 23, 2025.
- Hemorrhoids. Cleveland Clinic. Accessed October 26, 2026. Cleveland Clinic lists a last update of May 5, 2025.
- Treatment of Hemorrhoids. National Institute of Diabetes and Digestive and Kidney Diseases. Accessed October 26, 2026. NIDDK last reviewed this page in October 2016.
- Diagnosis of Hemorrhoids. National Institute of Diabetes and Digestive and Kidney Diseases. Accessed October 26, 2026. NIDDK last reviewed this page in October 2016.
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