L91.0Hypertrophic scar

L91.0 is the ICD-10-CM diagnosis code for hypertrophic scar. It belongs to category L91 (hypertrophic disorders of skin), block L80-L99 (other disorders of the skin and subcutaneous tissue) and chapter 12 (diseases of the skin and subcutaneous tissue). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Within L91 (hypertrophic disorders of skin), L91.0 is specifically for hypertrophic scar. Related codes cover other hypertrophic disorders of the skin (L91.8) and hypertrophic disorder of the skin, unspecified (L91.9).

The conditions in its Excludes2 note aren't part of L91.0, but may be coded alongside it if the patient has both: acne keloid (L73.0) and scar NOS (L90.5).

It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.

In MS-DRG v44.0, it is part of the grouping logic for DRG 606 (Minor Skin Disorders with MCC, relative weight 1.5728) and DRG 607 (Minor Skin Disorders without MCC, relative weight 0.8772), in MDC 09 (Diseases and Disorders of the Skin, Subcutaneous Tissue and Breast), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 701.4 (keloid scar).