L59.0 vs T67
L59.0 and T67 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 T67
erythema [dermatitis] ab igne (L59.0)
L59.0
Erythema ab igne [dermatitis ab igne]
Billable
- Chapter 12
- Diseases of the skin and subcutaneous tissue
- Section
- L55-L59
Indexed under
- Dermatitis › ab igne (eczematous)
- Dermatitis › calorica (eczematous)
- Dermatitis › combustionis (eczematous)
- Dermatitis › heat (eczematous)
- Erythema, erythematous › ab igne (infectional) (inflammation)
T67
Effects of heat and light
Not billable
- Chapter 19
- Injury, poisoning and certain other consequences of external causes
- Section
- T66-T78
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