Abstract and Introduction
While prompt diagnosis of vasculitis is important, recognition of vasculitis mimics is equally essential. As in the case of vasculitis, an approach to mimics based on the anatomic size of vessels can be useful. Infections can mimic vasculitis of any vessel size, including the formation of aneurysms and induction of ANCAs. Genetic disorders and vasculopathies are important considerations in large and medium vessel vasculitis. Cholesterol emboli, thrombotic conditions and calciphylaxis typically affect the medium and small vessels and, like vasculitis, can cause cutaneous, renal and CNS manifestations. Reversible cerebral vasoconstriction syndrome is important to distinguish from primary angiitis of the CNS. As an incorrect diagnosis of vasculitis can result in harmful consequences, it is imperative that the evaluation of suspected vasculitis includes consideration of mimics. We discuss the above mimics and outline a systematic and practical approach for differentiating vasculitis from its mimics.
The vasculitides encompass autoimmune conditions affecting the blood vessels and causing end organ damage. The 2012 International Chapel Hill Consensus Conference provides definitions for the different forms of vasculitis and also a framework to categorize them. In addition to large, medium and small vessel vasculitis, other categories include variable vessel vasculitis, single-organ vasculitis, vasculitis with probable aetiology and vasculitis associated with autoimmune diseases. Multiple conditions may mimic vasculitis.[2–5] While early diagnosis of vasculitis is important to induce remission and prevent organ damage, an incorrect diagnosis can result in harmful consequences from missing the underlying condition and exposure to immunosuppressive therapy. Evaluation of vasculitis should include consideration of its mimics. In this review we outline a systematic approach to mimics of vasculitis based on the anatomic size of the blood vessel affected and discuss clinical features that may allow differentiation of these mimics from vasculitis. Medications and illicit drugs like cocaine can cause vasculitis and are important in identifying secondary causes. However, they are 'vasculitis with probable aetiology' rather than mimics and are beyond the scope of this review.
Rheumatology. 2021;60(1):34-47. © 2021 Oxford University Press