L51.8 ICD-10-CM Code: Other erythema multiforme

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for L51.8 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 L51.8 itself; “inherited from” names the category or block whose note applies here.

Coder workflow for L51.8

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

Before you code L51.8

1. “Other” (NEC) means the condition is specified in the record but no dedicated code captures it. Confirm the documented form is not one a sibling code names before settling on L51.8; if the record states no specifics at all, the unspecified sibling applies instead. “Other” codes are for documented conditions the classification gives no specific code; “unspecified” codes are for records lacking the detail (Guidelines I.A.9.a, I.A.9.b).

   ReviewL51.0, L51.1, L51.2, L51.3

   See the relationships section · Guide: Other vs unspecified (NEC vs NOS) →

2. Check the Excludes1 note: if the documentation supports a condition named there, do not simply proceed with L51.8. 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

1. Does the documentation support a condition named in L51.8’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.

   ReviewL00, A69.2, L71

Consider L51.8. Then work the Use Additional Code note, and 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 conditions the Use Additional Code note names

Reported with this code when documented; a conditional instruction (“if applicable”, “if known”) applies only when the record supports it.

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 L51.8(4 notes)

  Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with L51.8: the two are not reported together. The one exception is when the record shows the two conditions are unrelated to each other.

  CompareL00, A69.2, L71

  See the official tabular notes · Guidelines I.A.12.a

• Use Additional Code — after identifying L51.8(14 notes)

  Coding workflow: Check whether the documentation supports the additional code(s) the note names, and report them with L51.8 when it does. Where the instruction is conditional (“if applicable”, “if known”), it applies only when the record documents the condition.

  ReviewM14.8, H11.42, H10.22, H17, H16.0, H02.84

  See the official tabular notes · Guidelines I.A.13

Coding decision scenarios

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

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.

Indexed Clinical Terms (1)

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.

• Erythema, erythematous (infectional) (inflammation), multiforme (major) (minor), specified NEC

Don’t confuse L51.8 with…

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

The codes most likely to be picked instead of L51.8 — 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.

• L00— 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 staphylococcal scalded skin syndrome moves the case to L00; the two are not reported together unless documented as unrelated.

  Full comparison: L51.8 vs L00 →

• A69.2— 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 Lyme disease moves the case to A69.2; the two are not reported together unless documented as unrelated.

  Full comparison: L51.8 vs A69.2 →

• L71— 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 rosacea moves the case to L71; the two are not reported together unless documented as unrelated.

  Full comparison: L51.8 vs L71 →

• L51.9— Specificity relationship (Review)

  Overlapping diagnoses in the same category.

  Overlapping codes in the same category — the documentation decides which is the more specific fit.

  What moves you there: A record that documents no more than “Erythema multiforme, unspecified” takes L51.9; specificity in the record moves it back here.

  Full comparison: L51.8 vs L51.9 →

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 L51.8 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 1 Code First instruction: M14.8 — Arthropathies in other specified diseases classified elsewhere (via L51.-).

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 595 (MDC 09), DRG 596 (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):SKN002 — Other specified inflammatory condition of skin (default); INJ031 — Allergic reactions.

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 categories (Other specified inflammatory condition of skin, Allergic reactions).

L50.3 — Dermatographic urticaria, L50.4 — Vibratory urticaria, L50.5 — Cholinergic urticaria, L50.6 — Contact urticaria, L50.8 — Other urticaria, L50.9 — Urticaria, unspecified, L51.0 — Nonbullous erythema multiforme, L51.1 — Stevens-Johnson syndrome, L51.2 — Toxic epidermal necrolysis [Lyell], L51.3 — Stevens-Johnson syndrome-toxic epidermal necrolysis overlap syndrome, L51.9 — Erythema multiforme, unspecified, L52 — Erythema nodosum, L53.0 — Toxic erythema, L53.1 — Erythema annulare centrifugum, L53.2 — Erythema marginatum, L53.3 — Other chronic figurate erythema, L53.8 — Other specified erythematous conditions, L53.9 — Erythematous condition, unspecified, L54 — Erythema in diseases classified elsewhere, L55.0 — Sunburn of first degree, +233 more

Same Index main term, other category

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

A26.0 — Cutaneous erysipeloid (migrans), A69.20 — Lyme disease, unspecified (chronicum migrans), B08.3 — Erythema infectiosum [fifth disease] (infectiosum), E52 — Niacin deficiency [pellagra] (endemic), I00 — Rheumatic fever without heart involvement (marginatum, inacute rheumatic fever), K14.1 — Geographic tongue (migrans, tongue), L12.0 — Bullous pemphigoid (multiforme, pemphigoides), L22 — Diaper dermatitis (napkin), L24.5 — Irritant contact dermatitis due to other chemical products (due to, chemical NEC, in contact with skin), L30.4 — Erythema intertrigo (intertrigo), L52 — Erythema nodosum (nodosum), L53.0 — Toxic erythema (toxic, toxicum NEC), L53.1 — Erythema annulare centrifugum (annulare), L53.2 — Erythema marginatum (marginatum), L53.3 — Other chronic figurate erythema (figuratum perstans), L53.8 — Other specified erythematous conditions (palmar), L53.9 — Erythematous condition, unspecified, L54 — Erythema in diseases classified elsewhere (in diseases classified elsewhere), L55.0 — Sunburn of first degree (solare), L59.0 — Erythema ab igne [dermatitis ab igne] (ab igne), +7 more

Contextual Map

Every relationship of L51.8 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 L51.8 with this related code 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
• L49-L54 — Urticaria and erythema[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

Referenced by Code First instructions

• M14.8 — Arthropathies in other specified diseases classified elsewhere[Code First](via L51.-): “erythema multiforme (L51.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Clinical classification (CCSR)

• SKN002 — Other specified inflammatory condition of skin[CCSR]— AHRQ CCSR for ICD-10-CM Diagnoses (HCUP)
• INJ031 — Allergic reactions[CCSR]— AHRQ CCSR for ICD-10-CM Diagnoses (HCUP)

MS-DRG Grouper

• DRG 595 — MAJOR SKIN DISORDERS WITH MCC[MS-DRG]: “MAJOR SKIN DISORDERS WITH MCC (MDC 09)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 596 — MAJOR SKIN DISORDERS WITHOUT MCC[MS-DRG]: “MAJOR 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

• Erythema, erythematous (infectional) (inflammation), multiforme (major) (minor), specified NEC[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026

Nearest codes

• L51 — Erythema multiforme[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• L51.0 — Nonbullous erythema multiforme[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• L51.1 — Stevens-Johnson syndrome[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• L51.2 — Toxic epidermal necrolysis [Lyell][Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• L51.3 — Stevens-Johnson syndrome-toxic epidermal necrolysis overlap syndrome[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• L51.9 — Erythema multiforme, unspecified[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

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

Nearest Codes in This Family

Official ICD-10-CM classifications closest to L51.8 in its code family, with their registry titles.

• L51 — Erythema multiforme
• L51.0 — Nonbullous erythema multiforme
• L51.1 — Stevens-Johnson syndrome
• L51.2 — Toxic epidermal necrolysis [Lyell]
• L51.3 — Stevens-Johnson syndrome-toxic epidermal necrolysis overlap syndrome
• L51.9 — Erythema multiforme, unspecified

View all codes in the L51 family