ICD-10-CM 2027
ICD-10 code for rash
Confirmed by the official ICD-10-CM index entry “rash (toxic)”. Page updated September 29, 2026.
About coding rash
The ICD-10-CM code for rash is R21 (Rash and other nonspecific skin eruption).
It is also searched as skin eruption.
Don't report R21 together with the conditions in its Excludes1 note: specified type of rash- code to condition and vesicular eruption (R23.8).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 606 (Minor Skin Disorders with MCC, relative weight 1.5728) and DRG 607 (Minor Skin Disorders without MCC, relative weight 0.8772), in MDC 09 (Diseases and Disorders of the Skin, Subcutaneous Tissue and Breast), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
Don't confuse with (Excludes1 for R21)
- specified type of rash- code to condition
- vesicular eruption (R23.8)
Common questions about rash ICD-10 codes
What is the ICD-10 code for rash?
- R21 — Rash and other nonspecific skin eruption.
Is R21 billable?
- Yes. R21 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can R21 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict R21 as a principal diagnosis.
Is R21 a CC or MCC?
- No. R21 is neither a CC nor an MCC under MS-DRG v44.0.