R21 Rash and other nonspecific skin eruption

Billable

Block: Symptoms and signs involving the skin and subcutaneous tissue (R20-R23)

Includes

  • rash NOS

Excludes 1 (cannot be coded together)

  • specified type of rash- code to condition
  • vesicular eruption (R23.8)
This category is a complete, billable diagnosis code.

No additional specificity is required — submit R21 directly on claims and documentation without a subcode extension.

Last reviewed: September 2026