ANCA-Associated Vasculitis—ENT Involvement

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) are idiopathic, immunologically mediated diseases predominantly affecting small vessels throughout the body (capillaries, venules arterioles, and small arteries), which are pathogenetically associated with pauci-immune vasculitis and with either proteinase 3-ANCA (PR3-ANCA or c-ANCA) or myeloperoxidase-ANCA (MPO-ANCA or p-ANCA). The 2012 revised Chapel Hill Consensus Conference (CHCC) defined microscopic polyangiitis (MPA), granulomatosis with polyangiitis (GPA, formerly Wegener’s granulomatosis), eosinophilic granulomatosis with polyangiitis (EGPA, also known as Churg–Strauss syndrome), and single-organ manifestations (e.g., acute renal-limited disease known as pauci-immune necrotizing crescentic glomerulonephritis, NCGN) as the main clinic-pathological variants within the AAV spectrum. Head and neck involvement in the course of AAV is a quite frequent finding, and not uncommonly a first and stand-alone sign of active disease. This is particularly true for GPA and EGPA, especially in limited forms of disease: for this reason, otorhinolaryngologists become key figures in the multidisciplinary team approaching these conditions, especially in the diagnostic phase. Collaterally to AAV, the so-called cocaine-induced midline destructive lesions (CIMDL) are emerging pathologies caused by habitual cocaine insufflation commonly presenting with clinical, endoscopic, serological, and histopathological features resembling those of systemic vasculitis. Differential diagnosis of CIMDL from a sinonasal, limited form of GPA is often challenging, owing to their large similarity and the reluctance of patients in admitting cocaine addiction: this must always be kept in mind in AAV diagnostic algorithms.