Excludes1 pair

L00 vs P39.4

L00 and P39.4 are not coded together. ICD-10-CM declares them mutually exclusive with an Excludes1 note — the two conditions are not expected to occur together, so exactly one of them is normally correct for a given encounter. The Official Guidelines carve out one exception: if the two conditions are clearly unrelated to each other, both may be reported.

The official note, declared on P39.4
pemphigus neonatorum (L00)
L00

Staphylococcal scalded skin syndrome

Billable
Chapter 12
Diseases of the skin and subcutaneous tissue
Section
L00-L08
Use when the record says
  • Ritter's disease
Indexed under
  • Ritter's disease
  • Staphylococcal scalded skin syndrome
  • Dermatitis › Ritter's (exfoliativa)
  • Disease, diseased › Ritter's
  • Syndrome › staphylococcal scalded skin
P39.4

Neonatal skin infection

Billable
Chapter 16
Certain conditions originating in the perinatal period
Section
P35-P39
Use when the record says
  • Neonatal pyoderma
Indexed under
  • Pyoderma, pyodermia › newborn
  • Infection, infected, infective › congenital › skin
  • Infection, infected, infective › newborn › skin
  • Infection, infected, infective › skin › newborn

These two codes sit in different chapters of the Tabular List, which is usually the clearest signal that they describe different underlying processes rather than different degrees of the same one.

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