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L01.00 vs M54.0

L01.00 (Impetigo, unspecified) compared with M54.0 (Panniculitis affecting regions of neck and back), from the official CMS tabular data.

Summary

These codes can be reported together when both conditions are documented, because L01.00 lists M54.0 under Excludes2, which marks them as distinct conditions.

Official rule
What is different?

The conditions named, billing status and chapter.L01.00 is “Impetigo, unspecified”; M54.0 is “Panniculitis affecting regions of neck and back”. M54.0 is a non-billable header; L01.00 is billable. L01.00 sits in L00-L99 — Diseases of the Skin and Subcutaneous Tissue (L00-L99); M54.0 in M00-M99 — Diseases of the Musculoskeletal System and Connective Tissue (M00-M99).

Registry fact

Can these codes be reported together?

Yes, when both are documented.L01.00 lists M54.0 under Excludes2: “panniculitis of neck and back (M54.0-)”. Excludes2 marks distinct conditions that may both be reported when both are documented.

Official ruleGuide: Excludes1 vs Excludes2

Is there an Excludes1 relationship?

None.Neither entry carries an Excludes1 note that names the other code. L01.00 carries 1 Excludes1 note and M54.0 carries 6 Excludes1 notes covering other codes; the side-by-side table quotes them.

Official rule

Is there an Excludes2 relationship?

Yes.L01.00’s tabular entry: “panniculitis of neck and back (M54.0-)”. The note covers M54.0.

Official ruleGuide: Excludes1 vs Excludes2

Is one more specific?

Not comparable.The codes sit in different categories; specificity is only comparable within one category.

Is one a parent or header code?

One is a header.M54.0 is a non-billable header, but L01.00 is not one of its subdivisions.

Registry fact

Are there sequencing instructions?

None.Neither entry carries a Code First or Use Additional Code note that names the other.

Official rule

Are there other coding relationships?

None found.No laterality, encounter-phase, Table of Neoplasms, Table of Drugs and Chemicals, or history-versus-active-disease relationship links these codes.

MedCoder-derived

Official rule: a tabular instructional note or a section of the ICD-10-CM Official Guidelines, quoted as published. Registry fact: the codes’ own published attributes (titles, billable status, position in the hierarchy, code set). MedCoder-derived: a reading MedCoder computes from those facts; it is not itself a rule. How to read the labels

Can these codes be reported together?

Informational

Excludes2 relationship

L01.00
Impetigo, unspecified
↔
M54.0
Panniculitis affecting regions of neck and back

What we found

Yes, when both are documented.L01.00 carries an Excludes2 note covering M54.0: “panniculitis of neck and back (M54.0-)”

Excludes2 marks distinct conditions — both may be reported when both are documented.

What to review

Report both only when the documentation supports both conditions; otherwise report the one documented.

Guide: Excludes1 vs Excludes2Check these on a claim

Why it matters

An Excludes2 note means the excluded condition is not part of the code above it, but a patient can have both. Report both when both are documented.

Source / rule

CMS ICD-10-CM tabular instructional notes

Official guidance behind these answers

  • Section I.A.12.b — Excludes2 · applies to: Excludes2

    A type 2 Excludes note represents “Not included here.” An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.

    ICD-10-CM Official Guidelines FY2026

Quoted from the ICD-10-CM Official Guidelines for Coding and Reporting in effect for the release shown. The tabular notes above are the code-level instruction; these sections are the convention that says how such a note is applied. Source document (CMS PDF) · Release and checksum

Side by side

L01.00Impetigo, unspecifiedM54.0Panniculitis affecting regions of neck and back
Billing statusBillableNon-billable header

Report instead: M54.00, M54.01, M54.02, M54.03, M54.04

ClassificationL00-L99 — Diseases of the Skin and Subcutaneous Tissue (L00-L99)M00-M99 — Diseases of the Musculoskeletal System and Connective Tissue (M00-M99)
DefinitionImpetigo, unspecified is a billable ICD-10-CM diagnosis code (L01.00).Panniculitis affecting regions of neck and back is a non-billable ICD-10-CM category code (M54.0).
Includes
Impetigo NOS
—
Excludes1
impetigo herpetiformis (L40.1)
lupus panniculitis (L93.2)
panniculitis NOS (M79.3)
relapsing [Weber-Christian] panniculitis (M35.6)
psychogenic dorsalgia (F45.41)
current injury - see injury of spine by body region
discitis NOS (M46.4-)
Excludes2
hordeolum (H00.0)
infective dermatitis (L30.3)
local infections of skin classified in Chapter 1
lupus panniculitis (L93.2)
panniculitis NOS (M79.3)
panniculitis of neck and back (M54.0-)
Perlèche NOS (K13.0)
Perlèche due to candidiasis (B37.0)
Perlèche due to riboflavin deficiency (E53.0)
pyogenic granuloma (L98.0)
relapsing panniculitis [Weber-Christian] (M35.6)
viral warts (B07.-)
zoster (B02.-)
—
Use additional code
code (B95-B97) to identify infectious agent.
—

Notes are the code’s own tabular entry, quoted as published. A note that names the other code is the one the verdict above rests on.

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Derived from the official CMS ICD-10-CM tabular data (FY2027). A coding-rule comparison, not billing advice: payer-specific edits and medical-necessity policy are outside its scope. All data sources