Table 5 Classification criteria for childhood polyarteritis nodosa.

A systemic illness characterised by the presence of either a biopsy showing small and mid‐size artery necrotising vasculitis OR angiographic abnormalities* (aneurysms or occlusions) (mandatory criteria), plus at least two of the following:

• Skin involvement (livedo reticularis, tender subcutaneous nodules, other vasculitic lesions)

• Myalgia or muscle tenderness

• Systemic hypertension, relative to childhood normative data

• Mononeuropathy or polyneuropathy

• Abnormal urine analysis and/or impaired renal function†

• Testicular pain or tenderness

• Signs or symptoms suggesting vasculitis of any other major organ system (gastrointestinal, cardiac, pulmonary, or central nervous system)

*Should include conventional angiography if magnetic resonance angiography is negative.

†Glomerular filtration rate of less than 50% normal for age.