2026 ICD-10-CM Diagnosis Code L66Cicatricial alopecia [scarring hair loss]

ICD-10-CM Codes›L00–L99›L60-L75›L66

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

L66 is a non-billable ICD-10-CM category code for cicatricial alopecia [scarring hair loss], so it cannot be submitted on claims. Use a more specific code from this category instead, such as L66.0, L66.10, L66.11, and L66.12.

Code Identity

ICD-10-CM Code
L66
Billable Status
No — Non-Billable Category
Code Describes
Cicatricial alopecia [scarring hair loss]
Chapter
L60-L75
Disorders of skin appendages

Code Classification

ChapterL00–L99Diseases of the skin and subcutaneous tissue
SectionL60-L75Disorders of skin appendages
CategoryL66Cicatricial alopecia [scarring hair loss]
This CodeL66Cicatricial alopecia [scarring hair loss]

Specific Coding for Cicatricial alopecia [scarring hair loss]Overview

Non-specific codes like L66 require more characters. Use one of these billable codes instead:

  • Use L66.0 for Pseudopelade

  • L66.1 for Lichen planopilaris

  • Use L66.10 for Lichen planopilaris, unspecified

  • Use L66.11 for Classic lichen planopilaris

  • Use L66.12 for Frontal fibrosing alopecia

  • Use L66.19 for Other lichen planopilaris

  • Use L66.2 for Folliculitis decalvans

  • Use L66.3 for Perifolliculitis capitis abscedens

  • Use L66.4 for Folliculitis ulerythematosa reticulata

  • L66.8 for Other cicatricial alopecia

  • Use L66.81 for Central centrifugal cicatricial alopecia

  • Use L66.89 for Other cicatricial alopecia

  • Use L66.9 for Cicatricial alopecia, unspecified

Patient EducationClinical

Hair Loss

You lose up to 100 hairs from your scalp every day. That's normal, and in most people, those hairs grow back. But many men -- and some women -- lose hair as they grow older. You can also lose your hair if you have certain diseases, such as thyroid problems, diabetes, or lupus.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About L66Overview

Is L66 (Cicatricial alopecia [scarring hair loss]) a billable code?

No. This is a category header that groups the codes for cicatricial alopecia [scarring hair loss], and headers cannot be submitted on claims. Claims for cicatricial alopecia [scarring hair loss] need a more specific code from this category, such as L66.0, L66.10, and L66.11.