Lymphocytic Vasculopathy With Cytoplasmic Antineutrophil Cytoplasmic Antibody Positivity After Upper Respiratory Infection: A Case Report.

Cutaneous manifestations of vasculitic or vasculopathic processes can pose a diagnostic challenge, particularly when systemic symptoms are absent. We report a case of an adult patient who presented with nonpainful petechiae and blue-purple discoloration of the lower extremities three days after a self-limited upper respiratory infection. Laboratory testing revealed elevated erythrocyte sedimentation rate, white blood cell count, and C-reactive protein, as well as positive cytoplasmic antineutrophil cytoplasmic antibody (c-ANCA) titers. No other systemic findings or organ involvement were identified. A punch biopsy of the affected skin demonstrated vascular changes with a differential diagnosis that included lymphocytic vasculopathy. The patient was managed with short-course systemic corticosteroids and close observation as the lesions gradually resolved without complications. This case highlights an atypical, skin-limited c-ANCA-associated lymphocytic vasculopathy, emphasizing the importance for physicians to maintain vigilance for subtle cutaneous signs of autoimmune or inflammatory disease even in the absence of systemic involvement.