Contralateral recurrence of allergic fungal rhinosinusitis after unilateral endoscopic sinus surgery: a case report

Allergic fungal rhinosinusitis (AFRS) is a chronic sinusitis resulting from type I and III hypersensitivity reactions to fungal antigens. We report a rare case of a 30-year-old woman with asthma, allergic dermatitis, and allergic rhinitis who developed contralateral recurrence of AFRS two months after undergoing endoscopic sinus surgery (ESS) for unilateral disease. Initial imaging showed left-sided sinus opacification, and histopathology confirmed AFRS. Despite postoperative steroid therapy and nasal irrigation, the patient developed right-sided symptoms. Computed tomography (CT) revealed new lesions in the right maxillary, anterior ethmoid, and frontal sinuses, and a second ESS confirmed recurrent AFRS. The patient’s systemic allergic predisposition and possible environmental fungal exposure may have contributed to the rapid contralateral recurrence. This case highlights the importance of viewing AFRS as a systemic condition. Long-term follow-up, evaluation of both sides, and management of allergic comorbidities are essential to reduce the risk of recurrence.