L03.31 ICD-10-CM Code: Cellulitis of trunk

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for L03.31 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 L03.31 itself; “inherited from” names the category or block whose note applies here.

Coder workflow for L03.31

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

Before you code L03.31

1. L03.31 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).

   ReviewL03.311, L03.312, L03.313, L03.314, L03.315, L03.316, L03.317, L03.319, L03.31A

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

Choose the right path

1. Does the documentation support one of the more specific codes beneath L03.31?
   Yes → Select that code and continue the checks below on its own page.
   No → L03.31 cannot be reported as written; query for the specificity its subcategory needs.

   ReviewL03.311, L03.312, L03.313, L03.314, L03.315, L03.316, L03.317, L03.319, L03.31A

Consider L03.31. 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

• Excludes2 — not part of L03.31(28 notes)

  Coding workflow: The conditions named in this note are not included in L03.31. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

  CompareK61, N61.0, N76.4, N48.2, N49, P38

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

• Use Additional Code — after identifying L03.31(1 note)

  Coding workflow: Check whether the documentation supports the additional code(s) the note names, and report them with L03.31 when it does. Where the instruction is conditional (“if applicable”, “if known”), it applies only when the record documents the condition.

  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 L03.31 with…

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

The codes most likely to be picked instead of L03.31 — 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.

• K61— 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 cellulitis of anal and rectal regions adds K61; it is not part of this code and both may be reported when both are documented.

  Full comparison: L03.31 vs K61 →

• N61.0— 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 cellulitis of breast NOS adds N61.0; it is not part of this code and both may be reported when both are documented.

  Full comparison: L03.31 vs N61.0 →

• N76.4— 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 cellulitis of female external genital organs adds N76.4; it is not part of this code and both may be reported when both are documented.

  Full comparison: L03.31 vs N76.4 →

• N48.2— 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 cellulitis of male external genital organs adds N48.2; it is not part of this code and both may be reported when both are documented.

  Full comparison: L03.31 vs N48.2 →

• N49— 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 cellulitis of male external genital organs adds N49; it is not part of this code and both may be reported when both are documented.

  Full comparison: L03.31 vs N49 →

• P38— 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 omphalitis of newborn adds P38; it is not part of this code and both may be reported when both are documented.

  Full comparison: L03.31 vs P38 →

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: L03.311, L03.312, L03.313, L03.314, L03.315.

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 L03.31 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 Excludes1 note: I89.1 — Lymphangitis (via L03.-).

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

Referenced by 4 Excludes2 notes: L89 — Pressure ulcer (via L03.-), L97 — Non-pressure chronic ulcer of lower limb, not elsewhere classified (via L03.-), L98.4 — Non-pressure chronic ulcer of skin, not elsewhere classified (via L03.-), L98.A — Non-pressure chronic ulcer of upper limb, not elsewhere classified (via L03.-).

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

Referenced by 1 Use Additional Code instruction: T65.84 — Toxic effect of xylazine (via L03.-).

These codes instruct coders to additionally report this code when it applies.

Contextual Map

Every relationship of L03.31 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 L03.31 with these 10 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

Excludes2

• K61 — Abscess of anal and rectal regions[Excludes2]: “cellulitis of anal and rectal regions (K61.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• N61.0 — Mastitis without abscess[Excludes2]: “cellulitis of breast NOS (N61.0)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• O91.2 — Nonpurulent mastitis associated with pregnancy, the puerperium and lactation[Excludes2]: “puerperal cellulitis of breast (O91.2)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• P38 — Omphalitis of newborn[Excludes2]: “omphalitis of newborn (P38.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Referenced by Excludes1 notes

• I89.1 — Lymphangitis[Excludes1](via L03.-): “acute lymphangitis (L03.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Referenced by Excludes2 notes

• L89 — Pressure ulcer[Excludes2](via L03.-): “skin infections (L00-L08)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• L97 — Non-pressure chronic ulcer of lower limb, not elsewhere classified[Excludes2](via L03.-): “skin infections (L00-L08)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• L98.4 — Non-pressure chronic ulcer of skin, not elsewhere classified[Excludes2](via L03.-): “skin infections (L00-L08)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• L98.A — Non-pressure chronic ulcer of upper limb, not elsewhere classified[Excludes2](via L03.-): “skin infections (L00-L08)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Referenced by Use Additional Code instructions

• T65.84 — Toxic effect of xylazine[Use Additional Code](via L03.-): “cellulitis and acute lymphangitis (L03.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Nearest codes (40)

• L03 — Cellulitis and acute lymphangitis[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• L03.115 — Cellulitis of right lower limb[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• L03.116 — Cellulitis of left lower limb[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• L03.119 — Cellulitis of unspecified part of limb[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• L03.12 — Acute lymphangitis of other parts of limb[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• L03.121 — Acute lymphangitis of right axilla[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• L03.122 — Acute lymphangitis of left axilla[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• L03.123 — Acute lymphangitis of right upper limb[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• and 32 more

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 L03.31 in its code family, with their registry titles.

• L03.213 — Periorbital cellulitis
• L03.22 — Cellulitis and acute lymphangitis of neck
• L03.221 — Cellulitis of neck
• L03.222 — Acute lymphangitis of neck
• L03.3 — Cellulitis and acute lymphangitis of trunk
• L03.311 — Cellulitis of abdominal wall
• L03.312 — Cellulitis of back [any part except buttock and flank]
• L03.313 — Cellulitis of chest wall
• L03.314 — Cellulitis of groin
• L03.315 — Cellulitis of perineum

View all codes in the L03 family