ACR Criteria for the Classification of Hypersensitivity Vasculitis
Three of the following five criteria were required to meet American College of Rheumatology (ACR) classification criteria for hypersensitivity vasculitis:
- Age at disease onset older than 16 years.
- Medication at disease onset as a precipitating factor.
- Palpable purpura.
- Maculopapular rash.
- Biopsy specimen showing granulocytes around an arteriole and venule.
These criteria have a reported sensitivity of 71% and a reported specificity of 83.9% for the classification of hypersensitivity vasculitis compared with other vasculitides.