Describe a case of EGPA after long COVID presenting with peripheral neuropathy, and negative antineutrophil cytoplasmic antibody (ANCA).

EGPA, formerly known as Churg-Strauss syndrome, a rare and potentially fatal systemic disorder, is characterized by Asthma, vasculitis, skin changes, hyper eosinophilia, and positive ANCA testing. Peripheral neuropathy with sensory deficits and pain is one of the presenting symptoms. Occasionally, EGPA presents as cranial nerve mononeuropathy. Rare cases of ANCA associated vasculitis have been reported during or soon after SARS-COV-2 and influenza infections. There is insufficient evidence that COVID-19 triggers EGPA.

A 46-year-old woman presented with 25-pound weight loss within six months, 3-day history of pain, swelling, paresthesia of the left foot, pain in her left calf followed 6 days later by severe pain and paresthesia of the right foot. She had 1-day of transient binocular, oblique diplopia, right dilated, non-reactive pupil, and temporal area pain. One year before, she had SARS-COV-2 infection followed by intermittent episodes of dry cough, and shortness of breath that required inhaled corticosteroids. Neurological examination revealed hypoesthesia of dorsum and sole of the left foot, brisk left patellar reflex, decreased left ankle jerk, and down going plantar reflex. There was mild erythema over dorsum of the left foot with minimal tenderness. Laboratory testing showed hyper eosinophilia, elevated white cell count, ESR, serum IgE level, and rheumatoid factor; C-reactive protein, cyclic citrullinated peptide and ANCA were negative. EMG/NCS showed prolonged right H-reflex. Right sural nerve and gastrocnemius biopsy demonstrated necrotizing arteriolitis, vascular and perivascular chronic infiltrates with numerous eosinophils and mononuclear cells. MRI revealed pansinusitis. She responded to oral steroids and Mepolizumab. 

This case highlights the importance of having vasculitis in the differential diagnosis in patients with painful neuropathy and prior SARS-COV-2 infection. Nerve and muscle biopsy is a useful tool in confirming the diagnosis.