ICD-10 Code L91.0 – Hypertrophic scar (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code L91.0 – Hypertrophic scar
What it is
Hypertrophic scar is an overgrown, raised scar that forms after skin injury or surgery. It stays within the original wound borders and can become thick, firm, or red.
Clinical signs
Typical findings include a raised, smooth, firm scar with persistent redness or itching. Clinical features vary; refer to documentation.
When to use this code
Use L91.0 when the record clearly documents a hypertrophic scar, including postoperative or traumatic scarring. Code it when the provider identifies the scar as hypertrophic rather than keloid or a routine healing scar. Check documentation if the scar type is unclear.
Do not use for
Do not use this code for keloids, which extend beyond the wound margin, or for normal scar formation without abnormal thickening. Check documentation if the note only says “scar” or “post-surgical scar.”
Coding tip
Assign L91.0 only when the provider specifically documents “hypertrophic scar” or equivalent wording.