ABSTRACT
Introduction: Eosinophilic fasciitis (EF) is an uncommon scleroderma-like disorder resulting from infiltration of eosinophils and other white blood cells into the fascia. The etiology of EF is frequently idiopathic, but triggers have included trauma, medications, infection, and autoimmune conditions. Case Description: We present a case of EF in a 16-year old female with a history of Hashimoto’s thyroiditis, food allergies, and allergic rhinitis. Two weeks following her 1st dose of the Pfizer mRNA SARS-CoV-2 vaccine, she presented with generalized edema, weight gain (for 2-3 months prior), and polyarthritis. She did not have any scleroderma-like skin changes. Laboratory analysis was remarkable for eosinophilia (2130 cells/uL), elevated aldolase (15.6 U/L), and normal creatinine kinase. Lupus testing was unremarkable. MRI of bilateral thighs showed fasciitis and muscle/fascial biopsy demonstrated inflammatory myofasciitis consistent with EF. Given pending parasite studies, she received ivermectin prior to IV methylprednisolone therapy. Our patient has demonstrated significant improvement on prednisone, methotrexate, intravenous immunoglobulin, and hydroxychloroquine. Infectious work-up revealed positive Toxocara IgG levels, which prompted albendazole treatment. Discussion: Our case demonstrates an interesting perspective on the rare diagnosis of eosinophilic fasciitis. The etiology of her EF is unclear with confounding factors including her history of Hashimoto’s thyroiditis, positive Toxocara serology (IgG positive, IgM testing not available), and temporal relationship to Pfizer SARS-CoV-2 vaccine. This vaccine could have triggered an inflammatory process in the patient’s already hyper-reactive immune system. It is important to promptly recognize EF, as prolonged symptoms prior to diagnosis is associated with a poor treatment response.