2026 ICD-10-CM Diagnosis Code L23.9Allergic contact dermatitis, unspecified cause

ICD-10-CM Codes›L00–L99›L20-L30›L23

ICD-10-CM L23.9
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

L23.9 is a billable ICD-10-CM diagnosis code for allergic contact dermatitis, unspecified cause. 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 Allergic reactions and Contact dermatitis.

Code Identity

ICD-10-CM Code
L23.9
Billable Status
Yes — Valid for Submission
Code Describes
Allergic contact dermatitis, unspecified cause
Short Description
Allergic contact dermatitis, unspecified cause
Same as the full description in the CMS dataset.
Parent Code
L23
Allergic contact dermatitis

Code Classification

ChapterL00–L99Diseases of the skin and subcutaneous tissue
SectionL20-L30Dermatitis and eczema
CategoryL23Allergic contact dermatitis
This CodeL23.9Allergic contact dermatitis, unspecified cause

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Allergic contact dermatitis
  • Allergic contact dermatitis of external auditory canal
  • Allergic contact dermatitis of face
  • Allergic contact dermatitis of female genitalia
  • Allergic contact dermatitis of foot
  • Allergic contact dermatitis of hands
  • Allergic contact dermatitis of lower leg
  • Allergic contact dermatitis of male genitalia
  • Allergic contact dermatitis of neck
  • Allergic contact dermatitis of perianal skin
  • Allergic contact dermatitis of scalp
  • Allergic contact sensitization of skin and skin-associated mucous membrane
  • Allergic contact urticaria
  • Allergic disorder of skin
  • Allergic sensitization
  • Allergic vulvitis
  • Chronic contact dermatitis
  • Contact dermatitis of external ear
  • Contact dermatitis of female genitalia
  • Contact dermatitis of foot
  • Contact dermatitis of lower leg
  • Contact dermatitis of male genitalia
  • Contact dermatitis of neck
  • Contact dermatitis of perianal skin
  • Contact dermatitis of scalp
  • Contact dermatitis of skin of left hand
  • Contact dermatitis of skin of right hand
  • Contact urticaria
  • Disseminated allergic contact urticaria
  • Exacerbation of constitutional dermatitis due to occupation
  • Exacerbation of constitutional dermatitis due to occupational exposure to contact allergen
  • Lichen simplex chronicus
  • Lichenoid allergic contact dermatitis
  • Lichenoid allergic contact reaction
  • Localized allergic contact urticaria
  • Occupational allergic contact dermatitis
  • Occupational allergic contact sensitization
  • Perianal dermatitis
  • Protein contact dermatitis
  • Systemic contact dermatitis

Tabular List NotesGuidance

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

Inclusion Terms

  • Allergic contact eczema 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)
      • contact (occupational)
        • allergic
    • Dermatitis(eczematous)
      • sensitization NOS

Clinical ClassificationClinical

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

CCSR INJ031
Allergic reactions
Default principal diagnosis: inpatient No · outpatient No
CCSR SKN005
Contact dermatitis
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Allergic Contact Dermatitis

    an inflammatory skin condition caused by an immune response to direct contact between the skin and an allergen. it consists of a delayed type of allergic reaction at the affected site with resulting red, swollen, and blistered skin that may itch or leak.

Patient EducationClinical

Allergy

An allergy is a reaction by your immune system to something that does not bother most other people. People who have allergies often are sensitive to more than one thing. Substances that often cause reactions are:

Read the full article at MedlinePlus

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

Convert L23.9 to ICD-9-CMHistory

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

ICD-9-CM
692.9 Dermatitis NOS
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 L23.9Overview

Is L23.9 (Allergic contact dermatitis) a billable code?

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

What MS-DRG does L23.9 group to?

When allergic contact dermatitis, unspecified cause 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 L23.9?

Under the General Equivalence Mappings, allergic contact dermatitis, unspecified cause converts to ICD-9-CM 692.9 (dermatitis NOS). 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.