2026 ICD-10-CM Diagnosis Code L66.10Lichen planopilaris, unspecified

ICD-10-CM Codes›L00–L99›L60-L75›L66

ICD-10-CM L66.10
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

L66.10 is a billable ICD-10-CM diagnosis code for lichen planopilaris, unspecified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 606 through 607. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified inflammatory condition of skin.

Code Identity

ICD-10-CM Code
L66.10
Billable Status
Yes — Valid for Submission
Code Describes
Lichen planopilaris, unspecified
Short Description
Lichen planopilaris, unspecified
Same as the full description in the CMS dataset.
Parent Code
L66.1
Lichen planopilaris

Code Classification

ChapterL00–L99Diseases of the skin and subcutaneous tissue
SectionL60-L75Disorders of skin appendages
CategoryL66Cicatricial alopecia [scarring hair loss]
This CodeL66.10Lichen planopilaris, unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Cicatricial alopecia due to lichen planus
  • Eczema of scalp
  • Eruption of female perineum
  • Eruption of vulva
  • Frontal fibrosing alopecia
  • Graham Little Piccardi Lassueur syndrome
  • Lichen planopilaris
  • Lichen planopilaris of vulva
  • Lichen planus of scalp
  • Postmenopausal frontal fibrosing alopecia
  • Rash of scalp

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Lichen
      • planopilaris

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR SKN002
Other specified inflammatory condition of skin
Default principal diagnosis: inpatient Yes · outpatient Yes

Code History & ChangesHistory

Replacement L66.10 replaces the following previously assigned code(s):

  • L66.1 - Lichen planopilaris
FY 2025AddedAdded to the ICD-10-CM code setEffective October 1, 2024.
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About L66.10Overview

Is L66.10 (Lichen planopilaris) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report lichen planopilaris, unspecified on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does L66.10 group to?

When lichen planopilaris, unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 606, 607, with relative weights from 0.9064 to 1.5132 depending on complications. Higher weights mean higher Medicare reimbursement.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.