ICD-10 Code L66.10 – Lichen planopilaris, unspecified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code L66.10 – Lichen planopilaris, unspecified
What it is
Lichen planopilaris is a scarring inflammatory hair loss disorder that affects the scalp. The unspecified code applies when the record identifies lichen planopilaris but does not document a more specific subtype.
Clinical signs
Typical findings include patchy hair loss with perifollicular inflammation, scale, and evidence of scarring. Clinical features vary; refer to documentation for the exact pattern and extent.
When to use this code
Use this code when the clinician documents lichen planopilaris without further detail. It also fits when the note confirms scarring alopecia due to lichen planopilaris but does not specify a subtype or location. Check documentation if the diagnosis is uncertain.
Do not use for
Do not use this code for nonscarring alopecia, alopecia areata, or hair loss from another documented cause. If the chart names a different scarring alopecia, code that condition instead.
Coding tip
Assign the unspecified code only when the record supports lichen planopilaris and no more specific term is documented.