Polyarteritis nodosa (PAN) is a necrotizing vasculitis of medium and small arteries that can be life-threatening without prompt recognition and treatment. Contemporary management, guided by the ACR/Vasculitis Foundation recommendations, is built on disease stratification, rapid control of severe disease, and steroid minimization.
Diagnosis and stratification
Diagnosis rests on clinical features, vascular imaging (abdominal angiography is particularly useful for detecting occult organ involvement), and tissue biopsy where feasible. PAN is classified as severe or non-severe according to the presence of end-organ damage (renal failure, CNS involvement, mesenteric ischemia), which drives the intensity of induction therapy.
Induction and maintenance
Glucocorticoids are first-line in all PAN — high-dose oral prednisone, or intravenous pulse methylprednisolone for severe cases. For life- or organ-threatening disease, cyclophosphamide is added, which both controls disease and enables a faster steroid taper; treatment is usually limited to 3–6 months to reduce toxicity. Once remission is achieved, azathioprine, methotrexate, or mycophenolate serve as maintenance and steroid-sparing agents.
Targeted therapy and special situations
The most important mechanistic insight concerns DADA2 (deficiency of adenosine deaminase 2), a rare monogenic form of PAN, typically early-onset and stroke-prone, for which TNF-α inhibitors are strongly recommended and highly effective. Tocilizumab has helped in isolated refractory cases, but rituximab — unlike in ANCA-associated vasculitis — has not shown consistent benefit and is not generally recommended. In cutaneous PAN, glucocorticoids plus azathioprine achieve high response rates and better drug survival than colchicine alone. Physical therapy aids recovery in those with motor involvement, and minimizing cumulative exposure to both steroids and cyclophosphamide remains a priority.
| Setting | Preferred therapy | Notes |
|---|---|---|
| Severe/organ-threatening | High-dose glucocorticoids + cyclophosphamide | Transition to maintenance after 3–6 months |
| Non-severe | Glucocorticoids | Moderate/low dose may suffice |
| Maintenance | Azathioprine, methotrexate, mycophenolate | Post-cyclophosphamide |
| DADA2-related | TNF-α inhibitors | Genetic form; markedly effective |
| Cutaneous PAN | Glucocorticoids + azathioprine | Better response than colchicine |
Further reading: 2021 ACR/Vasculitis Foundation PAN guideline; EULAR recommendations for EGPA and PAN (2023–2024); reviews of DADA2 and TNF inhibition.