L23 vs L30.9
L23 and L30.9 can never be reported together. ICD-10-CM declares them mutually exclusive with an Excludes1 note, meaning the two conditions cannot occur in the same patient — so exactly one of them is correct for any given encounter.
The official note, declared on L23
dermatitis NOS (L30.9)
L23
Allergic contact dermatitis
Not billable
- Chapter 12
- Diseases of the skin and subcutaneous tissue
- Section
- L20-L30
L30.9
Dermatitis, unspecified
BillableUnspecified
- Chapter 12
- Diseases of the skin and subcutaneous tissue
- Section
- L20-L30
Use when the record says
- Eczema NOS
Indexed under
- Dermatitis (eczematous)
- Eczema (acute) (chronic) (erythematous) (fissum) (rubrum) (squamous)
Excludes1 is not always absolute: where two conditions covered by the note are genuinely unrelated, CMS guidance permits reporting both. Document the reasoning rather than assuming it. More on Excludes1 vs Excludes2 · FY2027