Isolated lower limb medium-vessel vasculitis: a new entity?

A 47-year-old female was referred with bilateral ischaemic lesions affecting her toes with associated gangrene. Systemic examination was normal and her medical history was unremarkable. Close examination of the hands revealed splinter haemorrhages. Her feet were dusky in colour and the toes were dark and weeping, each becoming gangrenous, with erythema around the metatarsal phalangeal joint. Dorsalis pedis and posterior tibial pulses were intact with strong Doppler signals. Investigations for surgical pathology and malignancy were all negative as were routine blood tests and tests for autoimmune and viral markers. Vasculitis was diagnosed when her toes showed improvement with steroids, however, attempts to reduce the steroid dose were unsuccessful and azathioprine was introduced. Despite immunosuppression and immunomodulators, her toes deteriorated and were amputated. Histology revealed findings consistent with a medium-vessel vasculitis which antineutrophil cytoplasmic antibody was negative. A similar vasculitis has not been formally reported in the literature.