Excludes1 pair

L81- vs Q82.5

L81 and Q82.5 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 L81
birthmark NOS (Q82.5)
L81

Other disorders of pigmentation

Not billable
Chapter 12
Diseases of the skin and subcutaneous tissue
Section
L80-L99
Q82.5

Congenital non-neoplastic nevus

Billable
Chapter 17
Congenital malformations, deformations, chromosomal abnormalities, and genetic disorders
Section
Q80-Q89
Use when the record says
  • Birthmark NOS
  • Flammeus Nevus
  • Portwine Nevus
  • Sanguineous Nevus
  • Strawberry Nevus
  • Vascular Nevus NOS
  • Verrucous Nevus
Indexed under
  • Birthmark
  • Port wine nevus, mark, or stain
  • Mark › port wine
  • Mark › raspberry
  • Mark › strawberry

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