Cutaneous manifestations of anti-neutrophil cytoplasmic antibody associated vasculitis

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a distinct group of systemic vasculitis with severe multi-organ involvement. It includes three types: granulomatosis with polyangiitis (GPA), eosinophilic granulomatosis with polyangiitis (EGPA), and microscopic polyangiitis (MPA). Cutaneous manifestations are present at the time of presentation in around 35% of cases and are more frequently encountered in EGPA than in GPA or MPA. They can also occur during the course of the disease or mark a disease relapse. They can be classified into specific or non-specific according to the presence or absence of vasculitis, whether or not associated with granuloma, in skin biopsies. The most common presentation of vasculitic skin lesions in AAV is palpable purpura. Other manifestations include hemorrhagic blisters, tender subcutaneous nodules, livedo reticularis/racemosa, painful ulcers that may mimic pyoderma gangrenosum (PG), and digital gangrenes. A wide range of non-specific cutaneous manifestations can occur in association with AAV including urticarial rash, prurigo, sterile pustules, and oral lesions. The presence of cutaneous lesions is usually associated with severe organ involvement and systemic manifestations. Since skin lesions in AAV can occur in other types of vasculitis and in other disorders, attributing them to AAV requires meticulous clinical, laboratory, and serological correlation. Awareness of cutaneous lesions of AAV is important for all physicians working in the field of systemic vasculitis as a skin biopsy may provide an easy clue to diagnose AAV in such cases.