Necrotising Cutaneous Lesions in Anti Neutrophil Cytoplasmic Antibodies- Associated Vasculitis Mimicking Necrotising Fasciitis

Necrotising vasculitis is a very rare occurrence and commonly caused by an underlying autoimmune pathology. Anti Neutrophil Cytoplasmic Antibodies (ANCA) associated vasculitis is an established cause for cutaneous manifestations of necrotising vasculitis, and is associated with multisystemic involvement, in which presentations of one system may feature predominantly and lead to misdiagnosis. A 33-year-old male presented with acute history of shortness of breath and necrotising blisters over both his ankles and arms. He was initially provisionally diagnosed with necrotising fasciitis, which was eventually ruled out as the serological biomarkers (including low level of C3 and presence of cytoplasmic type of ANCA on indirect immunofluorescence) drew suspicion of an autoimmune pathology. A multidisciplinary approach led to the commencement of steroid, which improved the patient’s condition rapidly. The histological examination of sample from the skin biopsy later confirmed the diagnosis of ANCA-Associated Vasculitis (AAV). The patient eventually recovered with excellent outcomes. Despite its rarity, any abnormal skin lesion may be a subtle presentation of necrotising cutaneous vasculitis. A high index of suspicion through a multidisciplinary approach, coupled with meticulous investigative process including serological biomarkers and skin biopsy, helps to avoid misdiagnosis which may be detrimental to the patient.