A thrombosed hemorrhoid is an external hemorrhoid that has developed a blood clot inside it, turning what might have been a mild nuisance into a sudden, intense source of pain. These clots form in the swollen veins just outside the anus, creating a firm, tender lump that can appear bluish or dark purple under the skin. Pain is typically most intense in the first 48 hours and then gradually improves as the body reabsorbs the clot over the following weeks.
How a Thrombosed Hemorrhoid Forms
External hemorrhoids are swollen blood vessels that sit just beneath the skin around the anal opening. Under normal circumstances, they may cause mild itching or discomfort. Thrombosis happens when blood inside one of these swollen vessels pools and clots, rapidly increasing the size and pressure within the hemorrhoid. The result is a hard, painful lump at the anal verge that can range from pea-sized to grape-sized.
The clot itself isn’t dangerous in the way a blood clot in your leg or lungs would be. It’s a localized event. Your body treats it like any other small clot, gradually breaking it down and reabsorbing it. But until that process is complete, the swelling stretches the overlying skin, which is packed with nerve endings, and that’s what produces the sharp, throbbing pain.
What Causes Them
Anything that increases pressure on the veins around the anus can set the stage for thrombosis. The most common triggers include straining during bowel movements (especially with constipation or diarrhea), sitting for extended periods, and heavy lifting. Pregnancy is a particularly common cause because the growing uterus puts direct pressure on pelvic veins, blood volume increases significantly, and hormonal changes slow digestion, making constipation more likely.
Obesity, a low-fiber diet, and chronic coughing can also contribute. In many cases, people already have external hemorrhoids that have been relatively quiet until a burst of extra pressure, like a bout of constipation or a long car ride, triggers the clot.
Symptoms and What It Looks Like
Thrombosed external hemorrhoids present as painful, nonreducible lumps at the anal verge. Unlike internal hemorrhoids, which sit inside the rectum and often cause painless bleeding, these are right at the surface where you can see and feel them. The lump is typically firm and may appear bluish or dark purple because of the trapped blood beneath the skin.
The hallmark symptom is sudden, severe pain that peaks within the first two days. Sitting, walking, and bowel movements all tend to make it worse. Some people also notice bleeding if the skin over the clot becomes stretched thin enough to break open. Itching and swelling around the area are common as well.
How They Differ From an Abscess
A thrombosed hemorrhoid can look alarming, and it’s easy to confuse it with other conditions. A perianal abscess, for instance, also produces a painful lump near the anus, but an abscess is an infection filled with pus. It often comes with fever, redness that spreads outward, and worsening pain over days rather than the sudden onset typical of thrombosis. Hemorrhoids are not infections and don’t cause fever. If your lump is warm to the touch, increasingly red, or accompanied by a fever, that’s a different situation that needs prompt medical evaluation.
Natural Healing Timeline
Most thrombosed hemorrhoids resolve on their own. In a review of over 500 patients managed without surgery, the median time to noticeable symptom improvement was 5 days, with a range from 1 to 23 days. Complete resolution of symptoms took a median of 8 days, though some patients needed up to 45 days. The body reabsorbs the clot bit by bit, and pain tends to improve a little each day after the initial 48-hour peak.
Once the clot is gone, you may be left with a small skin tag where the hemorrhoid stretched the skin. These tags are harmless, though some people find them annoying. They don’t require treatment unless they cause hygiene issues or ongoing irritation.
When Surgical Removal Helps
If the pain is severe, a minor procedure called excision can remove the clot and the hemorrhoid tissue around it. According to the American Society of Colon and Rectal Surgeons, early surgical excision can reduce acute pain, speed up resolution, and lower the chance of the hemorrhoid coming back. In studies comparing surgery to conservative management, symptom resolution averaged about 4 days in the surgical group compared to 24 days without surgery.
A separate study of 150 patients found that pain levels on day 4 were lower with full excision than with either topical medication or a simpler procedure that only drains the clot (thrombectomy). Recurrence rates at one year were also lower with excision. The procedure is typically done under local anesthesia in an office or outpatient setting, and while there’s some soreness during healing, it’s often less discomfort than the thrombosed hemorrhoid itself was causing.
The key factor is timing. Excision works best when the hemorrhoid is still acutely painful. If you’re already several days past the peak and the pain is fading, the benefit of a procedure shrinks because your body is already doing the work.
Managing Pain at Home
For hemorrhoids that are resolving on their own, or while waiting for a procedure, sitz baths are one of the most effective comfort measures. Fill a bathtub or a plastic sitz basin with 3 to 4 inches of warm water, around 104°F (40°C), and soak for 15 to 20 minutes. Three to four baths a day can significantly reduce pain and itching. Plain warm water is all you need. Epsom salts, oils, and other additives can irritate the area and aren’t recommended unless specifically prescribed.
Over-the-counter pain relievers can help take the edge off, particularly during the first couple of days when pain peaks. Ice packs wrapped in a cloth and applied for 10 to 15 minutes at a time can reduce swelling. Keeping the area clean and dry, wearing loose cotton underwear, and avoiding prolonged sitting all help. Stool softeners or a fiber supplement can make bowel movements less painful by reducing the need to strain.
Reducing the Risk of Recurrence
Once you’ve had a thrombosed hemorrhoid, you’re more likely to get another one if the underlying causes aren’t addressed. The most impactful changes are dietary: getting 25 to 30 grams of fiber daily through fruits, vegetables, whole grains, or a fiber supplement, and drinking enough water to keep stools soft. The goal is bowel movements that pass easily without straining.
Avoid sitting on the toilet longer than necessary. Reading or scrolling on your phone extends the time your pelvic veins are under pressure. When you feel the urge to go, don’t delay, as waiting can lead to harder stools. If your work involves long periods of sitting, take short standing or walking breaks throughout the day. For those who lift heavy weights, exhaling during the lift rather than holding your breath reduces the spike in abdominal pressure that can stress hemorrhoid veins.