Idiopathic polyarteritis nodosa-does it still exist? Viewpoint 2: idiopathic polyarteritis nodosa is rare, but still exists.

Polyarteritis Nodosa (PAN), is the firstly described vasculitis and can be seen in paediatric and adult age. PAN has a heterozygous clinical picture including cutaneous, constitutional, musculoskeletal, gastrointestinal, and renal involvement. Description and splitting of other vasculitis, makes this medium vessel vasculitis, a very rare disease. Additionally, many subgroups of PAN have been defined and this effort let to move Hepatitis B virus-PAN to Vasculitis with probable aetiology. Anyhow, idiopathic PAN still exists and cohorts from various countries such as France, India, and Japan have been published. Rarity of PAN necessities global collaboration to highlight clinical features and genetics studies. GLOBAL-PAN is an ongoing collaborative project of EUVAS, VCRC and many national cohorts. This review covers the recent epidemiological data of PAN along with demographic and clinical characteristics of cohorts from all-over the world and GLOBAL-PAN.