A Case of Eosinophilic Sinusitis with Eosinophilic Granulomatous Vasculitis that Developed while Receiving Dupilumab

<p>Eosinophilic chronic rhinosinusitis (ECRS) is an intractable form of sinusitis that is resistant to conservative treatment and often recurs after surgery. In recent years, the human anti-human IL-4/13 receptor monoclonal antibody (Dupilumab), which inhibits IL-4/13 signaling and suppresses various inflammatory responses to reduce nasal polyps and improve olfactory dysfunction, has been attracting attention as a new therapeutic agent for patients with inadequate control of sinusitis by existing treatments. In this case, a patient developed recurrent polyps and olfactory dysfunction about 6 months after undergoing a second endoscopic sinus surgery and was then started on Dupilumab. However, 3 months after the start of treatment, the patient developed EGPA, leading to discontinuation of treatment. Eosinophilic granulomatosis with polyangiitis (EGPA) developed during treatment of recurrent ECRS with Dupilumab. EGPA and ECRS are both characterized by increased eosinophil counts and bronchial asthma, and since both concepts overlap, it is often difficult to diagnose EGPA in the early stages of the disease, while ECRS is being observed. Although Dupilmab is basically a safe drug among the biological drugs, we believe it is important to fully explain the risks before treatment, and carefully follow up with blood tests, interviews, and physical findings to determine if there are any subjective symptoms, such as a sudden rise in peripheral eosinophil counts or numbness in the extremities, as part of the evaluation for the occurrence of EGPA during treatment.</p>