A Case of Orbital Inflammation as the Initial Manifestation of Eosinophilic Granulomatosis with Polyangiitis Following Dupilumab administration, Successfully Treated with Mepolizumab.

Purpose: We report a case of eosinophilic granulomatosis with polyangiitis (EGPA), manifesting as orbital cellulitis and scleritis following anti-interleukin (IL)-4 receptor α antibody dupilumab treatment, which was successfully treated with anti-IL-5 antibody mepolizumab.

Methods: Slit-lamp examination, diagnostic imaging, and biopsy were performed.

Results: A 53-year-old male patient presented with sudden swelling of the left eyelid, severe conjunctival edema, and hyperemia. He had received dupilumab for 6 months for refractory nasal polyps. On initial examination, slit-lamp examination and computed tomography of the orbit revealed the orbital cellulitis and scleritis in his left eye. Although orbital swelling resolved by the administration of systemic steroids, scleritis persisted. Six months after initial presentation, the patient developed abdominal pain, vomiting, diarrhea, and skin rashes. Biopsy of upper gastrointestinal tract and skin revealed eosinophilic infiltration surrounding the blood vessel with an increase in peripheral blood eosinophil count. The patient was diagnosed with EGPA and subsequently started on subcutaneous anti-IL-5 antibody mepolizumab with systemic steroid. Following initiation of mepolizumab, his eosinophil counts normalized, gastroenteritis symptoms resolved, and refractory scleritis disappeared within a month. Topical and systemic steroids were discontinued after mepolizumab administration without recurrence.

Conclusions: This case highlights that physicians should be aware of the potential ocular side effects associated with biologics administration, such as those associated with EGPA.