Ischemic Necrosis of Bilateral Second Toes in the Absence of Macrovascular Disease or Primary Vasculitis: A Unique Case of Systemic Sclerosis Sine Scleroderma (ssSSc).

Systemic sclerosis sine scleroderma (ssSSc) is an uncommon subset of systemic sclerosis, characterized by internal organ involvement and autoimmune serologies in the absence of skin thickening. Diagnosis is frequently delayed due to the lack of cutaneous findings, particularly when vascular manifestations precede classical rheumatologic features. We report a compelling case of a 51-year-old woman who developed bilateral plantar second-toe ischemic necrosis despite having no diabetes, macrovascular disease, or known vasculitis. Extensive vascular imaging, including arterial duplex, ankle-brachial indices (ABIs), and toe photoplethysmography (PPG), was unremarkable. Serologic testing revealed a high-titer, centromere-pattern antinuclear antibody (ANA), and histopathology demonstrated thrombotic vasculopathy without features diagnostic of immune complex vasculitis. Nailfold capillaroscopy showed dilated capillary loops, and rheumatologic evaluation confirmed the diagnosis of ssSSc. The patient was treated conservatively with aspirin, nifedipine, and local wound care, resulting in complete epithelialization within eight weeks. This case highlights the importance of considering ssSSc in the differential diagnosis of unexplained digital ischemia - particularly in the lower extremities - and underscores the value of multidisciplinary collaboration in identifying rare autoimmune vascular syndromes presenting with limb-threatening ischemia.