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L23.6 vs L25.9

L23.6 (Allergic contact dermatitis due to food in contact with the skin) compared with L25.9 (Unspecified contact dermatitis, unspecified cause), from the official CMS tabular data.

Summary

These codes should not be reported together because L23.6’s tabular entry lists L25.9 under Excludes1.

Official rule
What is different?

The conditions named.L23.6 is “Allergic contact dermatitis due to food in contact with the skin”; L25.9 is “Unspecified contact dermatitis, unspecified cause”.

Registry fact

Can these codes be reported together?

No.L23.6’s entry carries an Excludes1 note covering L25.9: “contact dermatitis NOS (L25.9)”. Both may be reported only when the documentation shows the two conditions are unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

Official ruleGuide: Excludes1 vs Excludes2

Is there an Excludes1 relationship?

Yes.L23.6’s tabular entry: “contact dermatitis NOS (L25.9)”. The note covers L25.9.

Official ruleGuide: Excludes1 vs Excludes2

Is there an Excludes2 relationship?

None.Neither entry carries an Excludes2 note that names the other code. L23.6 carries 14 Excludes2 notes and L25.9 carries 11 Excludes2 notes covering other codes; the side-by-side table quotes them.

Official rule

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?

No.Both are billable codes, and neither contains the other.

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?

Conflict

Excludes1 conflict

L23.6
Allergic contact dermatitis due to food in contact with the skin
L25.9
Unspecified contact dermatitis, unspecified cause

What we found

No — do not report together.L23.6 carries an Excludes1 note covering L25.9: “contact dermatitis NOS (L25.9)”

Sole exception: when the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

What to review

Report one of the two. Both may be reported only when the documentation shows the two conditions are unrelated to each other.

Guide: Excludes1 vs Excludes2Check these on a claim

Why it matters

An Excludes1 note means the two conditions cannot occur together, so the pair should not be reported for the same encounter. The sole exception is when the conditions are documented as unrelated to each other.

Source / rule

CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a

Official guidance behind these answers

  • Section I.A.12.a — Excludes1 · applies to: Excludes1

    A type 1 Excludes note is a pure excludes note. It means “NOT CODED HERE!” An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition. An exception to the Excludes1 definition is the circumstance when the two conditions are unrelated to each other. If it is not clear whether the two conditions involving an Excludes1 note are related or not, query the provider. For example, code F45.8, Other somatoform disorders, has an Excludes1 note for "sleep related teeth grinding (G47.63)," because "teeth grinding" is an inclusion term under F45.8. Only one of these two codes should be assigned for teeth grinding. However psychogenic dysmenorrhea is also an inclusion term under F45.8, and a patient could have both this condition and sleep related teeth grinding. In this case, the two conditions are clearly unrelated to each other, and so it would be appropriate to report F45.8 and G47.63 together.

    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

L23.6Allergic contact dermatitis due to food in contact with the skinL25.9Unspecified contact dermatitis, unspecified cause
Billing statusBillableBillable
ClassificationL00-L99 — Diseases of the Skin and Subcutaneous Tissue (L00-L99)L00-L99 — Diseases of the Skin and Subcutaneous Tissue (L00-L99)
DefinitionAllergic contact dermatitis due to food in contact with the skin is a billable ICD-10-CM diagnosis code (L23.6).Unspecified contact dermatitis, unspecified cause is a billable ICD-10-CM diagnosis code (L25.9).
Includes
Contact dermatitis (occupational) NOS
Contact eczema (occupational) NOS
Excludes1
allergy NOS (T78.40)
contact dermatitis NOS (L25.9)
dermatitis NOS (L30.9)
allergic contact dermatitis (L23.-)
allergy NOS (T78.40)
dermatitis NOS (L30.9)
irritant contact dermatitis (L24.-)
Excludes2
dermatitis due to ingested food (L27.2)
dermatitis due to substances taken internally (L27.-)
dermatitis of eyelid (H01.1-)
diaper dermatitis (L22)
eczema of external ear (H60.5-)
irritant contact dermatitis (L24.-)
perioral dermatitis (L71.0)
radiation-related disorders of the skin and subcutaneous tissue (L55-L59)
chronic (childhood) granulomatous disease (D71-)
dermatitis gangrenosa (L08.0)
dermatitis herpetiformis (L13.0)
dry skin dermatitis (L85.3)
factitial dermatitis (L98.1)
stasis dermatitis (I87.2)
dermatitis due to ingested substances (L27.-)
dermatitis of eyelid (H01.1-)
eczema of external ear (H60.5-)
perioral dermatitis (L71.0)
radiation-related disorders of the skin and subcutaneous tissue (L55-L59)
chronic (childhood) granulomatous disease (D71-)
dermatitis gangrenosa (L08.0)
dermatitis herpetiformis (L13.0)
dry skin dermatitis (L85.3)
factitial dermatitis (L98.1)
stasis dermatitis (I87.2)

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.

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