Rhino-Orbital Mucormycosis Following COVID-19 Viral Vector Vaccination in an Immunocompetent Patient

Rhino-orbital mucormycosis is a rare, life-threatening opportunistic fungal infection, typically affecting immunocompromised patients. During the COVID-19 pandemic, increased cases were mainly linked to SARS-CoV-2 infection, diabetes, and corticosteroid exposure. We report a severe case in a previously healthy 44-year-old immunocompetent man who developed acute left-sided exophthalmos, ophthalmoplegia, severe visual loss, and systemic deterioration 10 days after AZD1222 COVID-19 vaccination. Clinical and radiologic findings suggested invasive rhino-orbital fungal disease, prompting immediate liposomal amphotericin B, broad-spectrum antibiotics, urgent endoscopic sinus surgery, and repeated orbital-sinonasal debridements with amphotericin B irrigation. Histopathological examination demonstrated broad aseptate hyphae with tissue necrosis, consistent with mucormycosis, while fungal culture and ITS sequencing identified Rhizopus arrhizus as the causative species. Therapy was later adjusted to include isavuconazole and antibacterial coverage for persistent inflammation and secondary colonization. Orbital and systemic improvement occurred within the first week, with globe preservation and marked proptosis reduction at 6 months, despite persistent ophthalmoplegia and residual light perception. Isavuconazole was continued for 2 years, with no recurrence during 3 years of follow-up. Although causality with vaccination cannot be established, the temporal association and biological plausibility warrant further investigation. Early suspicion and prompt combined medical-surgical management are essential in rapidly progressive orbital cellulitis.