Name: Irritant contact dermatitis, unspecified cause
Creator: MedCoder.ai

Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.

Coding at a Glance

Tabular directives: 1 inclusion term · 3 Excludes1 · 13 Excludes2

Inpatient Payment Groups (MS-DRG)

Potential MS-DRG participation — not a DRG assignment.

MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v43, Appendix B.

MS-DRG 606 — MINOR SKIN DISORDERS WITH MCC (MDC 09)
MS-DRG 607 — MINOR SKIN DISORDERS WITHOUT MCC (MDC 09)

A diagnosis appearing in a group's logic does not by itself determine the DRG assigned to a stay; the grouper uses the full claim.

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for L24.9 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2026Effective: October 1, 2025

Notes without a marker are published on L24.9 itself; “inherited from” names the category or block whose note applies here.

Inclusion Terms

Alternative terms the tabular list files under this code.

Irritant contact eczema NOS

Excludes1 — Not Coded Here

Conditions generally not reported together with this code (Excludes1) -- an error unless the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

allergy NOS (T78.40) Compare L24.9 vs T78.40 →
contact dermatitis NOS (L25.9) Compare L24.9 vs L25.9 →
dermatitis NOS (L30.9) Compare L24.9 vs L30.9 →

Source: inherited from L24

Excludes2 — Not Included Here

Conditions not covered by this code, but which may be reported alongside it when both are present.

allergic contact dermatitis (L23.-) inherited from L24Compare L24.9 vs L23 →
dermatitis due to substances taken internally (L27.-) inherited from L24Compare L24.9 vs L27 →
dermatitis of eyelid (H01.1-) inherited from L24Compare L24.9 vs H01.1 →
diaper dermatitis (L22) inherited from L24Compare L24.9 vs L22 →
eczema of external ear (H60.5-) inherited from L24Compare L24.9 vs H60.5 →
perioral dermatitis (L71.0) inherited from L20-L30Compare L24.9 vs L71.0 →
radiation-related disorders of the skin and subcutaneous tissue (L55-L59) inherited from L20-L30Compare L24.9 vs L55 →
chronic (childhood) granulomatous disease (D71-) inherited from L20-L30Compare L24.9 vs D71 →
dermatitis gangrenosa (L08.0) inherited from L20-L30Compare L24.9 vs L08.0 →
dermatitis herpetiformis (L13.0) inherited from L20-L30Compare L24.9 vs L13.0 →
dry skin dermatitis (L85.3) inherited from L20-L30Compare L24.9 vs L85.3 →
factitial dermatitis (L98.1) inherited from L20-L30Compare L24.9 vs L98.1 →
stasis dermatitis (I87.2) inherited from L20-L30Compare L24.9 vs I87.2 →

Coder workflow for L24.9

MedCoder structured workflow — derived from this code’s own official record

Before you code L24.9

Unspecified does not mean incorrect. When the record gives no greater specificity, L24.9 may be the appropriate code. Check the record for detail that supports a more specific sibling — in this subcategory the siblings differ by the presence or absence of the associated condition. An unspecified code is for records that do not provide the detail a more specific code needs; a query, not an assumption, is the route to specificity (Guidelines I.A.9.b, I.B.18).
ReviewL24.0, L24.1, L24.2, L24.3, L24.4, L24.5, L24.6, L24.7
See the relationships section · Guide: Other vs unspecified (NEC vs NOS) →
Check the Excludes1 note: if the documentation supports a condition named there, do not simply proceed with L24.9. Excludes1 conditions are not reported together with this code unless the record shows they are unrelated (Guidelines I.A.12.a).
See the official tabular notes

Choose the right path

Does the record document the detail a more specific sibling code needs?
Yes → Review the specific siblings in this subcategory.
No → Continue — L24.9 is appropriate when the documentation goes no further.
ReviewL24.0, L24.1, L24.2, L24.3, L24.4, L24.5, L24.6, L24.7
Does the documentation support a condition named in L24.9’s Excludes1 note?
Yes → Do not simply proceed: review the excluded code. Both are reported only when the record shows the two conditions are unrelated.
No → Continue.
ReviewT78.40, L25.9, L30.9

Consider L24.9. Then confirm the code is valid for the date of service in the Verify section.

Documentation check

The provider’s diagnostic statement: Codes are assigned from the provider’s documented diagnosis, not from clinical criteria, test values or a medication list (Guidelines I.A.19).
The associated condition or complication: Whether the associated condition the title names is documented; the “with” convention presumes some links, and a provider statement that the conditions are unrelated defeats it (Guidelines I.A.15).
Any detail beyond this code’s title: What the record states that a more specific sibling code would capture — or its absence, which itself supports the unspecified code.

Official instructions as workflow

Excludes1 — check before selecting L24.9(3 notes)
Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with L24.9: the two are not reported together. The one exception is when the record shows the two conditions are unrelated to each other.
CompareT78.40, L25.9, L30.9
See the official tabular notes · Guidelines I.A.12.a
Excludes2 — not part of L24.9(13 notes)
Coding workflow: The conditions named in this note are not included in L24.9. When the record documents both, both may be reported; the note is a boundary, not a prohibition.
CompareL23, L27, H01.1, L22, H60.5, L71.0
See the official tabular notes · Guidelines I.A.12.b

Coding decision scenarios

Pattern scenarios for this code’s structure — decision rules, not clinical cases

Documentation: The provider documents the condition in the terms of this code’s title and records no further detail.

Coding question: Is a more specific sibling code supportable?

Path: Review the specific siblings in this subcategory and what each requires the record to state.

Reason: A more specific code needs documentation of the distinguishing element; without it the unspecified code is appropriate, and a provider query is the route to specificity (Guidelines I.A.9.b, I.B.18).

ReviewL24.0, L24.1, L24.2, L24.3, L24.4, L24.5, L24.6, L24.7

Documentation: Both the condition L24.9 describes and a condition named in its Excludes1 note are documented for the same encounter.

Coding question: Can both codes be reported?

Path: Review the Excludes1 note and the excluded code, and look for a provider statement on whether the two conditions are related.

Reason: Excludes1 means the two are not coded together; the exception is when the record shows the conditions are unrelated to each other (Guidelines I.A.12.a).

ReviewT78.40, L25.9, L30.9

Every row is derived from this code’s own record — its title, tabular notes, 7th-character family and same-category siblings — with fixed MedCoder wording; nothing is inferred about a patient. The official notes and guideline text are in the sections each row links to, and they control.

Code Overview

Irritant contact dermatitis, unspecified cause is a billable ICD-10-CM diagnosis code (L24.9).

MedCoder summary Summary composed by MedCoder from this code's official ICD-10-CM record. The tabular instructional notes themselves appear verbatim below.

Indexed Clinical Terms (2)

Official source data — entries quoted as published, in the Index’s own lookup phrasing

Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code. These are alphabetic-index entries shown as the Index writes them — lookup phrasing, not necessarily the wording of a final diagnosis.

Don’t confuse L24.9 with…

MedCoder analysis — pairs from this code’s official notes, distinctions written by MedCoder

The codes most likely to be picked instead of L24.9 — named in its own official notes, or sharing its laterality or encounter family — with what separates them and which documentation moves the case. Each links to the full comparison.

T78.40— Excludes1 conflict (Excludes1 — generally not reported together)
Not coded here — the tabular list excludes this pair for the same encounter.
Not reported together with this code, except where the two conditions are documented as unrelated.
What moves you there: Documentation of allergy NOS moves the case to T78.40; the two are not reported together unless documented as unrelated.
Full comparison: L24.9 vs T78.40 →
L25.9— Excludes1 conflict (Excludes1 — generally not reported together)
Not coded here — the tabular list excludes this pair for the same encounter.
Not reported together with this code, except where the two conditions are documented as unrelated.
What moves you there: Documentation of contact dermatitis NOS moves the case to L25.9; the two are not reported together unless documented as unrelated.
Full comparison: L24.9 vs L25.9 →
L30.9— Excludes1 conflict (Excludes1 — generally not reported together)
Not coded here — the tabular list excludes this pair for the same encounter.
Not reported together with this code, except where the two conditions are documented as unrelated.
What moves you there: Documentation of dermatitis NOS moves the case to L30.9; the two are not reported together unless documented as unrelated.
Full comparison: L24.9 vs L30.9 →
L23— Excludes2 relationship (Informational)
Distinct conditions — both may be reported.
A distinct condition — both may be reported when both are documented.
What moves you there: Documentation of allergic contact dermatitis adds L23; it is not part of this code and both may be reported when both are documented.
Full comparison: L24.9 vs L23 →
L27— Excludes2 relationship (Informational)
Distinct conditions — both may be reported.
A distinct condition — both may be reported when both are documented.
What moves you there: Documentation of dermatitis due to substances taken internally adds L27; it is not part of this code and both may be reported when both are documented.
Full comparison: L24.9 vs L27 →
H01.1— Excludes2 relationship (Informational)
Distinct conditions — both may be reported.
A distinct condition — both may be reported when both are documented.
What moves you there: Documentation of dermatitis of eyelid adds H01.1; it is not part of this code and both may be reported when both are documented.
Full comparison: L24.9 vs H01.1 →

Relationships are read from this code's own official notes, its laterality siblings and its encounter family; the wording of each distinction is MedCoder editorial, and the documentation named in each “what moves you there” line is the official note phrase or sibling title itself. Source: CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a.

Verify Before Coding

No Medicare Code Editor or MS-DRG Definitions Manual restrictions apply to this code.

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim in Claim Check.

Relationships & Classification

MedCoder structured relationships — computed from published CMS and AHRQ datasets

Other codes that name L24.9 or its code family, from the CMS ICD-10-CM tabular instructional notes. Tabular-note edges are stored at the code family level that carries each note.

Referenced by 3 Excludes1 notes across 2 chapters: L25 — Unspecified contact dermatitis (via L24.-), L53 — Other erythematous conditions (via L24.-), T78.4 — Other and unspecified allergy (via L24.-).

These codes’ tabular lists mark this diagnosis as mutually exclusive — not reported together unless the conditions are documented as unrelated.

Referenced by 3 Excludes2 notes: L23 — Allergic contact dermatitis (via L24.-), L27 — Dermatitis due to substances taken internally (via L24.-), L30 — Other and unspecified dermatitis (via L24.-).

These codes’ tabular lists name this diagnosis as distinct — both may be reported when both are documented.

Each of these codes carries a Code First note naming this condition — when that code is reported, THIS code is sequenced first, ahead of it.

MS-DRG Grouper Relationships (FY2026)

Potential MS-DRG participation — not a DRG assignment.

FY2026 MS-DRG: not on the CMS CC/MCC list — as a secondary diagnosis this code does not change MS-DRG severity for that release.

Named in the grouper logic of 2 MS-DRGs: DRG 606 (MDC 09), DRG 607 (MDC 09).

From the CMS MS-DRG Definitions Manual (Appendices B and C). Actual DRG assignment depends on the complete claim.

Clinical classification (AHRQ CCSR):SKN005 — Contact dermatitis (default).

Clinical Classifications Software Refined (CCSR) for ICD-10-CM Diagnoses. Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

Related Codes

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Contact dermatitis).

Same Index main term, other category

The ICD-10-CM Index to Diseases and Injuries files this code under the main term “Dermatitis”; these codes share that main term but sit in a different category of the Tabular List.

Contextual Map

Every relationship of L24.9 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Run L24.9 with these 14 related codes in Claim Check

Hierarchy

L00-L99 — Chapter 12: Diseases of the Skin and Subcutaneous Tissue (L00-L99) (L00-L99)[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
L20-L30 — Dermatitis and eczema[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

Referenced by Excludes1 notes

L25 — Unspecified contact dermatitis[Excludes1](via L24.-): “irritant contact dermatitis (L24.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
L53 — Other erythematous conditions[Excludes1](via L24.-): “erythema due to external agents in contact with skin (L23-L25)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
T78.4 — Other and unspecified allergy[Excludes1](via L24.-): “dermatitis (L23-L25, L27.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Referenced by Excludes2 notes

L23 — Allergic contact dermatitis[Excludes2](via L24.-): “irritant contact dermatitis (L24.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
L27 — Dermatitis due to substances taken internally[Excludes2](via L24.-): “contact dermatitis (L23-L25)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
L30 — Other and unspecified dermatitis[Excludes2](via L24.-): “contact dermatitis (L23-L25)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Referenced by Code First instructions (22)

F54 — Psychological and behavioral factors associated with disorders or diseases classified elsewhere[Code First](via L24.-): “dermatitis (L23-L25)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
T36 — Poisoning by, adverse effect of and underdosing of systemic antibiotics[Code First](via L24.-): “contact dermatitis (L23-L25)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
T36-T39 — Antibiotics & Anti-infectives (T36-T39)[Code First](via L24.-): “contact dermatitis (L23-L25)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
T36-T50 — Poisoning by, adverse effects of and underdosing of drugs, medicaments and biological substances (T36-T50)[Code First](via L24.-): “contact dermatitis (L23-L25)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
T37 — Poisoning by, adverse effect of and underdosing of other systemic anti-infectives and antiparasitics[Code First](via L24.-): “contact dermatitis (L23-L25)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
T38 — Poisoning by, adverse effect of and underdosing of hormones and their synthetic substitutes and antagonists, not elsewhere classified[Code First](via L24.-): “contact dermatitis (L23-L25)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
T39 — Poisoning by, adverse effect of and underdosing of nonopioid analgesics, antipyretics and antirheumatics[Code First](via L24.-): “contact dermatitis (L23-L25)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
T40 — Poisoning by, adverse effect of and underdosing of narcotics and psychodysleptics [hallucinogens][Code First](via L24.-): “contact dermatitis (L23-L25)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
and 14 more

Clinical classification (CCSR)

SKN005 — Contact dermatitis[CCSR]— AHRQ CCSR for ICD-10-CM Diagnoses (HCUP)

MS-DRG Grouper

DRG 606 — MINOR SKIN DISORDERS WITH MCC[MS-DRG]: “MINOR SKIN DISORDERS WITH MCC (MDC 09)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
DRG 607 — MINOR SKIN DISORDERS WITHOUT MCC[MS-DRG]: “MINOR SKIN DISORDERS WITHOUT MCC (MDC 09)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026

MDC crossing

MDC 09 — Diseases and Disorders of the Skin, Subcutaneous Tissue and Breast[MDC crossing]: “Diseases and Disorders of the Skin, Subcutaneous Tissue and Breast — the grouper's crossing between diagnoses and procedures: a principal diagnosis sets the MDC, and same-MDC procedures move the stay to its surgical DRGs. 7,376 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2026

Index entries

Dermatitis (eczematous), contact (occupational), irritant[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
Dermatitis (eczematous), due to, external irritant NEC[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026

Nearest codes (22)

L24 — Irritant contact dermatitis[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
L24.0 — Irritant contact dermatitis due to detergents[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
L24.1 — Irritant contact dermatitis due to oils and greases[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
L24.2 — Irritant contact dermatitis due to solvents[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
L24.3 — Irritant contact dermatitis due to cosmetics[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
L24.4 — Irritant contact dermatitis due to drugs in contact with skin[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
L24.5 — Irritant contact dermatitis due to other chemical products[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
L24.6 — Irritant contact dermatitis due to food in contact with skin[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
and 14 more

Change history

FY2016 — In the code set at ICD-10-CM adoption [Change history]— CMS release files (code change ledger) · icd10cm-fy2016

Sources for this page

Codes, titles, notes, index terms and mappings on this page are transcribed from the datasets below. Relationships MedCoder computed and text MedCoder wrote are labelled where they appear.

Code, title, tabular notes and index terms Official source data: CMS/CDC ICD-10-CM FY2026 tabular list, index and tables, effective October 1, 2025 Release, file and checksum · Publisher’s page
Claim edits Official source data: CMS Definitions of Medicare Code Edits — v43.1 (April 2026) Release, file and checksum · Publisher’s page
Inpatient payment groups Official source data: CMS MS-DRG Definitions Manual (incl. Appendix B diagnosis index, Appendix C CC/MCC list, Appendix E procedure index) and IPPS Final Rule tables — v43 Release, file and checksum · Publisher’s page
Change history and date-of-service validity Official source data: CMS ICD-10-CM release addenda, ingested release by release into the change ledger Release, file and checksum · Publisher’s page
Comparisons, relationships and the contextual map MedCoder structured relationship: Computed by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears
Summary and FAQ answers MedCoder explanation: Written by MedCoder to explain the sources above: drafted with AI assistance, checked by a person against the release files, and labelled as MedCoder text where it appears. Not official text.

Labels on this page: Official source data · MedCoder structured relationship · MedCoder explanation. How to read the labels · All data sources and release dates

Cite this page

Reference this page in a research guide, syllabus or article. The release is included because code content changes each year.

MedCoder.ai. "L24.9 — Irritant contact dermatitis, unspecified cause." ICD-10-CM FY2026. https://medcoder.ai/icd10/code/l24.9-irritant-contact-dermatitis-unspecified-cause

Change history

FY2016 — October 1, 2015
In the code set at ICD-10-CM adoption
Irritant contact dermatitis, unspecified cause

No changes since FY2016 — additions, deletions, description changes and billable-status changes are tracked through FY2027 (effective October 1, 2026), and none are recorded for this code. Note changes are tracked from FY2027 only.

Nearest Codes in This Family

Official ICD-10-CM classifications closest to L24.9 in its code family, with their registry titles.

View all codes in the L24 family

L24.9 ICD-10-CM Code: Irritant contact dermatitis, unspecified cause

Coding at a Glance

Inpatient Payment Groups (MS-DRG)

Coding instructions

Inclusion Terms

Excludes1 — Not Coded Here

Excludes2 — Not Included Here

Coder workflow for L24.9

Before you code L24.9

Choose the right path

Documentation check

Official instructions as workflow

Coding decision scenarios

Code Overview

Indexed Clinical Terms (2)

Don’t confuse L24.9 with…

Verify Before Coding

Relationships & Classification

MS-DRG Grouper Relationships (FY2026)

Related Codes

Same clinical category (CCSR)

Same Index main term, other category

Contextual Map

Hierarchy

Referenced by Excludes1 notes

Referenced by Excludes2 notes

Referenced by Code First instructions (22)

Clinical classification (CCSR)

MS-DRG Grouper

MDC crossing

Index entries

Nearest codes (22)

Change history

Sources for this page

Cite this page

Change history

Nearest Codes in This Family