Characteristics of External Hemorrhoids on Physical Examination
External hemorrhoids are located below the dentate line, covered by anoderm and perianal skin, and are visible during external examination without requiring anoscopy. 1
Key Physical Examination Findings
Location and Appearance
- Located below the dentate line (the boundary between upper and lower anal canal)
- Covered by anoderm and perianal skin
- Directly visible during external examination without special equipment
- Appear as skin-covered vascular cushions around the anal verge 1, 2
Normal vs. Thrombosed External Hemorrhoids
Normal External Hemorrhoids:
- Soft, skin-colored or slightly bluish protrusions
- Usually asymptomatic unless irritated or inflamed
- May appear as skin tags when not engorged
Thrombosed External Hemorrhoids:
- Acutely painful, firm, bluish-purple swelling
- Well-circumscribed, tense nodule
- Often unilateral and can develop suddenly
- Size typically ranges from small pea to grape-sized lesion 3
- More prevalent on the left side (51% of cases) 4
Distinguishing Features from Internal Hemorrhoids
| Feature | External Hemorrhoids | Internal Hemorrhoids |
|---|---|---|
| Location | Below dentate line | Above dentate line |
| Covering | Anoderm/perianal skin | Rectal mucosa |
| Visualization | Visible on external exam | Require anoscopy |
| Innervation | Somatic (painful) | Visceral (typically painless) |
| Classification | Not graded | Graded I-IV based on prolapse |
Common Examination Pitfalls
- Don't confuse external hemorrhoids with anal skin tags (residual tissue from previous hemorrhoids)
- Never attribute fecal occult blood to hemorrhoids without proper evaluation 1
- Don't miss concurrent conditions like anal fissures, perianal abscess, or colorectal cancer 1
- Avoid confusing rectal varices with hemorrhoids, especially in patients with portal hypertension 1, 5
Special Examination Considerations
- In thrombosed external hemorrhoids, look for signs of necrosis or ulceration of overlying skin
- Note that external hemorrhoids are more common in males (2:1 ratio compared to females) 4
- Examine for mixed hemorrhoidal disease (concurrent internal and external hemorrhoids) 2
- Document size, location, number, and whether there is evidence of bleeding or discharge
Remember that while external hemorrhoids are readily visible on examination, a complete anorectal examination including anoscopy is essential for comprehensive evaluation, as up to 20% of hemorrhoid patients have concurrent anal fissures 1.