Infection associated Vasculitides.

Infections can mimic Primary Systemic Vasculitis. Many clinical features and investigations maybe very similar between the two conditions. It is very important for the clinician to be aware of the various infections which mimic vasculitis, since inadvertent immunosuppression in these patients can be fatal. Infections can mimic small, medium or large vessel vasculitis. Infections can produce autoantibodies such as Anti-neutrophil cytoplasmic antibody through molecular mimicry and could confound clinical judgement. In addition to the many infections causing vasculitis, more recently COVID-19 associated vasculitis has been described. The exact pathogenesis of infection associated vasculitis is not clear although direct spread, immune complex deposition and T/B cell activation are proposed. Infection as an etiological agent for primary systemic vasculitis has long been debated but definite evidence for the same is lacking. Many drugs used in daily clinical practice can rarely cause vasculitis. More recently Immune-check point inhibitors-induced vasculitis has been described.