Excludes1 pair

L93.2 vs M79.3

L93.2 and M79.3 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 M79.3
lupus panniculitis (L93.2)
L93.2

Other local lupus erythematosus

Billable
Chapter 12
Diseases of the skin and subcutaneous tissue
Section
L80-L99
Use when the record says
  • Lupus erythematosus profundus
  • Lupus panniculitis
Indexed under
  • Lupus › panniculitis
  • Panniculitis › lupus
  • Lupus › erythematosus › profundus
  • Lupus › erythematosus › specified NEC
M79.3

Panniculitis, unspecified

BillableUnspecified
Chapter 13
Diseases of the musculoskeletal system and connective tissue
Section
M70-M79
Indexed under
  • Lipodermatosclerosis
  • Panniculitis (nodular) (nonsuppurative)

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