Resistant Oral Candidiasis in a Post-Radical Neck Dissection Patient: A Case Report

Background: Oral candidiasis is a frequent opportunistic fungal infection in patients undergoing multimodal therapy for head and neck malignancies. Increasing azole resistance poses a significant therapeutic challenge and may lead to persistent lesions mistaken for tumor recurrence. Case Presentation: We report a 73-year-old male with a history of radical neck dissection, radiotherapy, chemotherapy, and targeted therapy who presented with diffuse pseudomembranous plaques and severe xerostomia. Mycological culture identified Candida albicans resistant to fluconazole and itraconazole. The patient was treated with a short-course intravenous voriconazole regimen (200 mg once daily for five days), resulting in complete clinical resolution and improved oral comfort. Discussion: Multimodal treatment for head and neck malignancy disrupts mucosal immunity and salivary gland function, predisposing patients to resistant fungal infection. Culture-guided antifungal selection is essential to prevent treatment failure. In this case, individualized voriconazole therapy demonstrated successful clinical response without systemic involvement, supporting the utility of targeted therapy in azole-resistant infections. However, further studies are necessary to validate this shortened dosing strategy. Conclusion: Resistant oral candidiasis should be considered in post-treatment head and neck cancer patients with persistent mucosal lesions. Early microbiological confirmation and appropriate systemic antifungal therapy are critical for effective management and to avoid misdiagnosis as recurrence. Keywords: oral candidiasis, azole resistance, voriconazole, radical neck dissection, chemotherapy, radiotherapy, xerostomia