2026 ICD-10-CM Diagnosis Code L21.9Seborrheic dermatitis, unspecified

ICD-10-CM Codes›L00–L99›L20-L30›L21

ICD-10-CM L21.9
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

L21.9 is a billable ICD-10-CM diagnosis code for seborrheic dermatitis, 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
L21.9
Billable Status
Yes — Valid for Submission
Code Describes
Seborrheic dermatitis, unspecified
Short Description
Seborrheic dermatitis, unspecified
Same as the full description in the CMS dataset.
Parent Code
L21
Seborrheic dermatitis

Code Classification

ChapterL00–L99Diseases of the skin and subcutaneous tissue
SectionL20-L30Dermatitis and eczema
CategoryL21Seborrheic dermatitis
This CodeL21.9Seborrheic dermatitis, unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Acute seborrheic dermatitis
  • Chronic seborrheic dermatitis
  • Disorder of skin due to human immunodeficiency virus infection
  • Generalized seborrheic dermatitis
  • Genitocrural seborrheic dermatitis
  • Perianal dermatitis
  • Perianal seborrheic dermatitis
  • Seborrhea faciei
  • Seborrheic blepharitis
  • Seborrheic dermatitis
  • Seborrheic dermatitis due to human immunodeficiency virus infection
  • Seborrheic eczema-like eruption
  • Truncal seborrheic dermatitis

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Seborrhea NOS

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.

    • Dermatitis(eczematous)
      • seborrheic
    • Seborrhea, seborrheic
    • Seborrhea, seborrheic
      • dermatitis
    • Seborrhea, seborrheic
      • eczema

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

Patient EducationClinical

Dandruff, Cradle Cap, and Other Scalp Conditions

Your scalp is the skin on the top of your head. Unless you have hair loss, hair grows on your scalp. Different skin problems can affect your scalp.

Read the full article at MedlinePlus

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

Convert L21.9 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
690.10 Sebrrheic dermatitis NOS
Approximate The match is approximate rather than exact.
ICD-9-CM
706.3 Seborrhea
Approximate The match is approximate rather than exact.

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 L21.9Overview

Is L21.9 (Seborrheic dermatitis) a billable code?

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

What MS-DRG does L21.9 group to?

When seborrheic dermatitis, 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.

What is the ICD-9 equivalent of L21.9?

Under the General Equivalence Mappings, seborrheic dermatitis, unspecified converts to ICD-9-CM 690.10 (sebrrheic dermatitis NOS) and 706.3 (seborrhea). The mapping is approximate, so confirm the match fits the documentation.

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.