ICD-10 Code K61.31 – Horseshoe abscess (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code K61.31 – Horseshoe abscess
What it is
K61.31 identifies a horseshoe-shaped abscess around the anal region, usually involving the perianal space. Use it when documentation specifically describes this pattern of abscess formation.
Clinical signs
Typical findings include pain, swelling, and tenderness around the anus, sometimes with drainage or fever. Clinical features vary; refer to documentation.
When to use this code
Use K61.31 when the provider documents a horseshoe abscess or a perianal abscess extending in a horseshoe pattern. Code it from the documented diagnosis, not from symptoms alone. If the record only says “perianal abscess,” check documentation for the specific anatomic pattern.
Do not use for
Do not use this code for a simple perianal abscess without horseshoe involvement. Also avoid it when the diagnosis is unclear or another anorectal condition is documented instead; check documentation.
Coding tip
Look for wording such as “horseshoe,” “bilateral perianal extension,” or similar anatomic detail before assigning K61.31.