2026 ICD-10-CM Diagnosis Code L21.8Other seborrheic dermatitis

ICD-10-CM Codes›L00–L99›L20-L30›L21

ICD-10-CM L21.8
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

L21.8 is a billable ICD-10-CM diagnosis code for other seborrheic dermatitis. 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
L21.8
Billable Status
Yes — Valid for Submission
Code Describes
Other seborrheic dermatitis
Short Description
Other seborrheic dermatitis
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 CodeL21.8Other seborrheic dermatitis

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Acute generalized seborrheic dermatitis
  • Acute seborrheic dermatitis
  • Diffuse dermatitis
  • Erythematosquamous dermatosis
  • Erythrodermic seborrheic dermatitis
  • Flexural seborrheic dermatitis
  • Greasy skin
  • Neonatal sebaceous gland hyperplasia
  • Parakeratosis
  • Physiological anomaly of neonatal skin
  • Pityriasiform seborrheic dermatitis
  • Post-encephalitic seborrhea
  • Sebaceous hyperplasia
  • Seborrhea adiposa
  • Seborrhea corporis
  • Seborrhea faciei
  • Seborrhea nasi
  • Senile sebaceous gland hyperplasia

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
        • specified NEC

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

Clinical InformationClinical

  • Parakeratosis

    persistence of the nuclei of the keratinocytes into the stratum corneum of the skin. this is a normal state only in the epithelium of true mucous membranes in the mouth and vagina. (dorland, 27th ed)

  • Parapsoriasis

    the term applied to a group of relatively uncommon inflammatory, maculopapular, scaly eruptions of unknown etiology and resistant to conventional treatment. eruptions are both psoriatic and lichenoid in appearance, but the diseases are distinct from psoriasis, lichen planus, or other recognized dermatoses. proposed nomenclature divides parapsoriasis into two distinct subgroups, pityriasis lichenoides and parapsoriasis en plaques (small- and large-plaque parapsoriasis).

  • Pityriasis Lichenoides

    a subgroup of parapsoriasis itself divided into acute and chronic forms. the acute form is characterized by the abrupt onset of a generalized, reddish-brown, maculopapular eruption. lesions may be vesicular, hemorrhagic, crusted, or necrotic. histologically the disease is characterized by epidermal necrolysis. the chronic form shows milder skin changes with necrosis.

  • Hyperparakeratosis

    a morphologic finding indicating increased keratin formation, preservation of the nuclei in the superficial cells, and absence of the stratum granulosum in a skin or squamous mucosa sample.

  • Parakeratosis

    abnormal retention of nuclei, and the resulting incomplete keratinization, of epithelial cells in the stratum corneum layer of the skin.

  • Tobacco Induced Hyperparakeratosis

    hyperparakeratosis of the oral mucosa caused by chronic tobacco use. it manifests as oral leukoplakia.

  • Sebaceous Hyperplasia

    enlargement of the sebaceous glands.

  • Senile Sebaceous Hyperplasia

    a hyperplasia of the sebaceous glands. it is usually seen as small yellow papules in the face of middle aged-older population.

  • Erythematosquamous Dermatosis

    a skin condition that primarily affects the scalp and face and presents as scaly inflammation. examples include itchy, dry skin and dandruff.

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 L21.8 to ICD-9-CMHistory

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

ICD-9-CM
690.18 Sebrrheic dermatitis NEC
Exact Match The mapping is direct, with no qualifiers.

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 L21.8Overview

Is L21.8 (Seborrheic dermatitis) a billable code?

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

What MS-DRG does L21.8 group to?

When other seborrheic dermatitis 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 L21.8?

Under the General Equivalence Mappings, other seborrheic dermatitis converts to ICD-9-CM 690.18 (sebrrheic dermatitis NEC). The mapping is a direct match.

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.