Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare systemic vasculitis characterized by extravascular granulomas, eosinophilia, and tissue infiltration by eosinophils. Antineutrophil cytoplasmic autoantibodies (ANCA) is positive in 30-40% of these patients.

A 65-year-old woman presented with chief complaint of allodynia and numbness in her legs. She also reported weakness in her proximal upper and lower extremities. Past medical history was significant for asthma, lupus, Hashimoto’s thyroiditis, and possible Addison’s disease. Patient had been completely weaned off from chronic steroid therapy about 13 months prior to admission. Over the past 6 months, patient reported extreme nausea and lack of appetite, along with unintentional weight loss of 100 lbs.

Routine lab work was significant initially for a mild neutrophilic predominant leukocytosis (WBC 12.2 with 90% neutrophils) but she developed an eosinophilia of 10.7% on differential (absolute 1.2 K/cumm with WBC 11.4) during her hospital stay. MRI of the pelvis and lumbar spine was concerning for a myositis of the iliopsoas, gluteal muscles, and adductor muscles with relative sparing of the quadriceps and hamstring muscles. A nerve conduction study and electromyography showed severe length dependent chronic sensorimotor axonal polyneuropathy. Eosinophilic granulomatosis with polyangitis (EGPA) was suspected; however, p-neutrophil cytoplasmic autoantibody/ANCA/anti-myeloperoxidase (MPO) antibodies were negative. A biopsy of her finger lesion revealed a leukocytoclastic vasculitis with overlying epidermal necrosis and prominent sweat gland necrosis . Patient was started on cyclophosphamide chemotherapy, with subsequent return of her appetite, stabilization of her leg numbness/tingling, and improvement in energy levels.

We here report a case of ANCA negative EGPA in a patient with multiple autoimmune disorders. We consider that there is a possible overlap in the pathogenesis of these disease, which may lead to interaction during the course of the diseases.