Defining treatment guidelines for polyarteritis nodosa (PAN) is complicated by the evolving definition and classification of this vasculitis, and because clinical trials have included patients with PAN, microscopic polyangiitis or, sometimes, Churg-Strauss syndrome. Nonetheless, clinical trial data support that the 'idiopathic generalised' form of PAN benefits from a severity-adapted treatment strategy, implying that cases with life-threatening manifestations require a regimen combining high-dose glucocorticoids and cyclophosphamide, whereas a non-severe disease may be treated with glucocorticoids alone. Results of uncontrolled studies indicate that hepatitis B virus-associated PAN management should include an antiviral agent, short-term glucocorticoids and plasma exchanges. No robust scientific evidence is available to guide the treatment of the limited variant 'cutaneous PAN'. Most experts recommend a less aggressive therapy with non-steroidal anti-inflammatory drugs or other agents, such as colchicine or dapsone. PAN has become an even more uncommon disease, probably due to classification changes and, perhaps also to a genuine modification of the epidemiology of this vasculitis. Although more data are needed to resolve outstanding questions, it is unclear whether all these matters can be studied in the future in large, sufficiently powered trials.