L51 ICD-10-CM Code: Erythema multiforme

Coding instructions

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

Coder workflow for L51

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

Before you code L51

1. L51 is not reportable as written. Select the more specific code beneath it that the documentation supports. Codes are reported to the highest level of specificity the classification provides (Guidelines I.B.2).

   ReviewL51.0, L51.1, L51.2, L51.3, L51.8, L51.9

   See the relationships section · Guide: How to choose an ICD-10-CM code →

2. Check the Excludes1 note: if the documentation supports a condition named there, do not simply proceed with L51. 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 one of the more specific codes beneath L51?
   Yes → Select that code and continue the checks below on its own page.
   No → L51 cannot be reported as written; query for the specificity its subcategory needs.

   ReviewL51.0, L51.1, L51.2, L51.3, L51.8, L51.9

2. Does the documentation support a condition named in L51’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. 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.

Official instructions as workflow

• Excludes1 — check before selecting L51(4 notes)

  Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with L51: 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(14 notes)

  Coding workflow: Check whether the documentation supports the additional code(s) the note names, and report them with L51 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.

Don’t confuse L51 with…

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

The codes most likely to be picked instead of L51 — 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 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 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 vs L71 →

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

• Not billable as written — a more specific code is required: L51.0, L51.1, L51.2, L51.3, L51.8.

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 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.

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.

Contextual Map

Every relationship of L51 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 with these 12 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
• L49-L54 — Urticaria and erythema[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

Excludes1

• A69.2 — Lyme disease[Excludes1]: “Lyme disease (A69.2-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• L00 — Staphylococcal scalded skin syndrome[Excludes1]: “staphylococcal scalded skin syndrome (L00)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• L71 — Rosacea[Excludes1]: “rosacea (L71.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Use Additional Code (27)

• H01.8 — Other specified inflammations of eyelid[Use Additional Code]: “inflammation of eyelid (H01.8-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• H02.22 — Mechanical lagophthalmos[Use Additional Code]: “mechanical lagophthalmos (H02.22-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• H02.84 — Edema of eyelid[Use Additional Code]: “edema of eyelid (H02.84-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• H10.22 — Pseudomembranous conjunctivitis[Use Additional Code]: “conjunctivitis (H10.22-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• H11.23 — Symblepharon[Use Additional Code]: “symblepharon (H11.23-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• H11.42 — Conjunctival edema[Use Additional Code]: “conjunctival edema (H11.42)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• H16.0 — Corneal ulcer[Use Additional Code]: “corneal ulcer (H16.0-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• H16.22 — Keratoconjunctivitis sicca, not specified as Sjögren's[Use Additional Code]: “keratoconjunctivitis sicca (H16.22-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• and 19 more

Referenced by Code First instructions

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

Nearest codes

• 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
• L51.8 — Other erythema multiforme[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

Common coding questions

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

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 in its code family, with their registry titles.

• 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
• L51.8 — Other erythema multiforme
• L51.9 — Erythema multiforme, unspecified