Vasculitis mimics

Idiopathic vasculitides are rare inflammatory systemic diseases grouped in the Chapel-Hill concensus nomenclature by the size of the predominantly affected vessels (large, medium, small and variable vessel vasculitis). Vasculitis mimics are syndromes that cause a clinical image similar to idiopathic vasculitides or can easily be confused with them. Sometimes they even cause the full-blown clinical and histological pattern of a vasculitis disease. There are numerous vasculitis mimics: depending on the affected vessel size, hereditary connective tissue diseases, genetic immunodeficiency and autoinflammatory syndromes, infectious diseases, rare inflammatory systemic diseases, malignancies, drug-induced syndromes and several others should be considered. This review presents a selection of classical mimickers of vasculitides grouped by vessel size and discusses constellations that can be typical "pitfalls " in the clinical workup.