Can anal fissures appear as a chunk of skin missing instead of a classic slit?

Anal Fissures: Appearance and Characteristics

Yes, anal fissures can appear as a chunk of skin missing rather than a classic slit, particularly in chronic cases where tissue loss and remodeling have occurred. 1, 2

Typical Appearance of Anal Fissures

• Anal fissures are classically described as longitudinal tears or splits in the squamous epithelium at or just inside the anal verge, which can extend from the dentate line to the anal verge 1, 2
• Approximately 90% of anal fissures occur posteriorly in the midline of the anal canal, with the remainder occurring anteriorly 1
• Anterior midline fissures occur in approximately 10% of women versus only 1% of men 1

Chronic Fissure Appearance

• Chronic fissures (those persisting longer than 8-12 weeks) may develop characteristics that make them appear as "chunks" of missing tissue rather than simple slits 3, 4
• Signs of chronicity that contribute to this appearance include:
  • A sentinel skin tag just distal to the fissure 1, 2
  • Hypertrophied anal papilla at the proximal margin 1, 2
  • Fibrosis at the base of the fissure 1, 2
  • Visible internal sphincter muscle at the fissure base (giving the appearance of deeper tissue loss) 1, 2

Diagnostic Considerations

• Anal fissures are best visualized by effacing the anal canal with opposing traction on the buttocks, not through digital rectal examination 2
• Digital rectal examination may actually be contraindicated in suspected anal fissures due to the severe pain it can cause 2
• In cases of severe pain, examination under anesthesia may be warranted to properly assess the fissure 2

When to Suspect Other Conditions

• Atypical fissure locations (lateral or multiple fissures) or unusual appearances should raise suspicion for underlying conditions 1, 2
• Conditions to consider with atypical presentations include:
  • Inflammatory bowel disease (IBD) 1
  • Sexually transmitted infections (HIV, syphilis, herpes) 1
  • Anorectal cancer 1, 2
  • Tuberculosis 1
  • Leukemia 1
  • Other infectious causes 1

Imaging Considerations

• Imaging is not typically needed for diagnosis of typical anal fissures 2
• However, imaging may be warranted in atypical presentations to rule out:
  • Occult perianal sepsis 2
  • Complex anal fistula 2
  • Underlying inflammatory bowel disease 2
  • Anal or colorectal cancer 2

Common Diagnostic Pitfalls

• Anal pain is often mistakenly attributed to hemorrhoids when it may actually be due to anal fissure, perianal abscess, or anal fistula 2
• Approximately 20% of patients with hemorrhoids have concomitant anal fissures, highlighting the importance of thorough visual examination 2
• The diagnosis of anal fissure should be suspected based on history alone, including anal pain during and after defecation, and scanty bright red bleeding 2