How to Explain External Hemorrhoids to a Patient
External hemorrhoids are swollen blood vessels located under the skin around the anus, below an internal landmark called the dentate line, and they typically only cause symptoms when a blood clot forms inside them (thrombosis) or when they become so large that cleaning becomes difficult. 1
What External Hemorrhoids Are
- External hemorrhoids develop from the perianal marginal veins located below the dentate line, which is the boundary between the upper and lower anal canal 2, 3
- These are distinct from internal hemorrhoids, which develop above this line from different vascular structures 1
- Unlike internal hemorrhoids that commonly bleed and prolapse, external hemorrhoids become symptomatic primarily when thrombosed or when skin tags interfere with hygiene 1
When External Hemorrhoids Cause Problems
The most common presentation is acute thrombosis, where a blood clot forms inside the hemorrhoid:
- Patients experience sudden-onset anal pain and notice a palpable perianal lump 1
- The typical patient is relatively young (mean age 36 years) and often has preceding constipation 4
- Pain is the prominent symptom with external hemorrhoids, unlike internal hemorrhoids where bleeding dominates 3
- Occasionally, thrombosed external hemorrhoids bleed when local pressure causes erosion through the overlying skin 1
What Causes Them
- Stagnation of blood and trauma to anal vessels from straining during bowel movements is the common mechanism 4
- Constipation, increased intra-abdominal pressure, and prolonged straining predispose to hemorrhoid development 5
- However, the American Gastroenterological Association emphasizes that rigorous proof for most commonly believed risk factors is lacking, including inadequate fiber intake, prolonged sitting on the toilet, and chronic straining 6
What to Expect
- Thrombosed external hemorrhoids are usually self-limiting and subside within a few days to a week with conservative management 4
- If the thrombosed hemorrhoid is seen within 72 hours of symptom onset, surgical excision provides the most rapid relief and reduces risk of repeat thrombosis 2
- After 72 hours, medical treatment with stool softeners and analgesics (such as 5% lidocaine) is recommended as the clot begins to organize 2
Important Distinctions
- External hemorrhoids rarely require surgery unless acutely thrombosed 2
- Pain with external hemorrhoids suggests thrombosis; if pain occurs without a visible thrombosed hemorrhoid, other pathology such as anal fissure or small abscess should be considered 1
- Up to 20% of patients with hemorrhoids have concomitant anal fissures, which cause severe postdefecatory pain 1
Prevention and Management
- Softening the stool is key to preventing excessive strain and reducing risk of thrombosis 4
- Increasing dietary fiber and water intake while avoiding straining during defecation forms the foundation of treatment 2
- For non-thrombosed external hemorrhoids that are simply skin tags, treatment is only needed if they interfere with hygiene 1