L01 vs L40.1
L01 and L40.1 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 L01
impetigo herpetiformis (L40.1)
L40.1
Generalized pustular psoriasis
Billable
- Chapter 12
- Diseases of the skin and subcutaneous tissue
- Section
- L40-L45
Use when the record says
- Impetigo herpetiformis
- Von Zumbusch's disease
Indexed under
- Von Zumbusch's disease
- Impetigo › herpetiformis (any organism) (any site) (circinate) (contagiosa) (simplex) (vulgaris)
- Psoriasis › pustular
- Impetigo › herpetiformis › nonobstetrical (any organism) (any site) (circinate) (contagiosa) (simplex) (vulgaris)
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