Abstract A 71-year-old male with asthma, chronic rhinosinusitis with nasal polyps, and peripheral eosinophilia was treated with Dupixent (dupilumab) for asthma control. Despite ongoing therapies, his symptoms of chronic cough and nasal congestion worsened. After receiving 2-3 doses of Dupixent, he developed recurrent fevers, with a maximum temperature of 102.5 °F, and worsening eosinophilia. Chest imaging revealed pneumonia-like findings, but sputum cultures, respiratory pathogen panels, and procalcitonin were negative. Bronchoscopy showed no eosinophils, but biopsy revealed eosinophilic infiltration. A bone marrow biopsy confirmed eosinophilia, leading to a diagnosis of hypereosinophilic syndrome. His eosinophil count decreased from 3.78 to 1.86 B/L after starting 60 mg prednisone daily. Clinical improvement followed, with reduced fever and respiratory symptoms. This case demonstrates a rare but significant complication of biologic therapy with Dupixent, a monoclonal antibody targeting interleukin-4 receptors. While Dupixent is highly effective in controlling asthma and chronic rhinosinusitis, it can sometimes exacerbate or induce eosinophilic disorders, such as hypereosinophilic syndrome. Dupixent’s mechanism of action, by modulating eosinophilic inflammation, may cause eosinophils to accumulate in tissues, leading to inflammation and damage 1. In this patient, despite initial improvements in his asthma, the drug likely contributed to the exacerbation of eosinophilic infiltration in various tissues, including the lungs and bone marrow, as evidenced by biopsy findings 2. The patient’s persistent eosinophilia and fever, coupled with negative infectious workups, suggest a drug-induced eosinophilic syndrome rather than an infectious or autoimmune etiology 3. Corticosteroids are the first-line therapy for managing eosinophilic inflammation and effectively reduce eosinophil counts and symptoms. In this case, steroid therapy led to a marked decrease in eosinophil count and clinical improvement, highlighting their critical role in managing this condition 4. This case emphasizes the importance of monitoring for eosinophilic side effects in patients on biologic therapies, especially those with a history of eosinophilia or allergic conditions. A comprehensive diagnostic approach, including imaging, bronchoscopy, biopsy, and bone marrow examination, is crucial for diagnosing drug-induced eosinophilic syndromes and ruling out other potential causes 2. Early intervention with corticosteroids can prevent significant organ damage and improve patient outcomes. While Dupixent remains an effective therapy for many patients with asthma and chronic rhinosinusitis, its potential to induce eosinophilic disorders necessitates careful patient selection, close monitoring, and timely intervention 14. This abstract is funded by: none
Walz et al. (Fri,) studied this question.