2027 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 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

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]
Short Description
Cicatricial alopecia [scarring hair loss]
Same as the full description in the CMS dataset.
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

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to L66: its own notes plus those printed at block L60-L75 and Chapter 12. A note printed at a category, block or chapter applies to every code under it.

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

From Block L60-L75 Disorders of skin appendages applies to 85 codes
  • congenital malformations of integument (Q84.-)

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From Chapter 12 (L00-L99) Diseases of the skin and subcutaneous tissue applies to 1,001 codes
  • certain conditions originating in the perinatal period (P04-P96)
  • certain infectious and parasitic diseases (A00-B99)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • lipomelanotic reticulosis (I89.8)
  • neoplasms (C00-D49)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
  • systemic connective tissue disorders (M30-M36)
  • viral warts (B07.-)

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

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 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About L66Overview

What is the ICD-10 code for cicatricial alopecia [scarring hair loss]?

L66 is the ICD-10-CM category for cicatricial alopecia [scarring hair loss], but it is a non-billable header: claims need a more specific code from this category, listed on this page.

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.

Can L66 be reported with a code from Q84?

Not as a rule. The Excludes1 note at block L60-L75, which applies to L66, lists "congenital malformations of integument (Q84.-)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).