Aims: 18F-fluorodeoxyglucose Positron Emission Tomography (FDG PET) represents an emerging imaging modality for skull base osteomyelitis (SBO) and malignant otitis externa (MOE), yet diagnostic performance and treatment monitoring utility remain inadequately characterised. This review examines the clinical utility of FDG PET for diagnosis and response assessment. Methods: A systematic search of MEDLINE, EMBASE, CINAHL, Web of Science and CENTRAL was undertaken for studies examining the role of FDG PET in diagnosis and/or treatment response monitoring of SBO and MOE. 242 studies were screened. Where reported, Standardised Uptake Value (SUV) and Lesion-to-Background Ratio (LBR) were extracted for analysis. Results: Eleven studies were included (3 diagnostic; n=122, 8 monitoring; n=207). Diagnostic studies demonstrated 96-100% sensitivity and 93% specificity for FDG PET, comparable to MRI. Bacterial infections showed higher SUVmax than fungal lesions (8.3±2.1 vs 4.7±1.8, p=0.002). In treatment monitoring, metabolic response outperformed inflammatory markers for predicting remission. Quantitative thresholds (SUVmax LBR ≥4.1, SUVpeak ≥3.11) achieved 67-100% specificity for recurrence prediction. Recurrence rates were 12-25% with PET-guided cessation versus higher rates with biomarker-based decisions. Substantial heterogeneity existed in protocols and thresholds. Among both studies (n=28) that compared accuracy of treatment response assessments between FDG PET and leukocyte scintigraphy (LS), PET was superior. Conclusion: In the literature, FDG PET demonstrates high diagnostic accuracy and superior prognostic value versus biomarkers and LS. These findings align with observations that FDG PET provides reliable assessment of active disease where conventional imaging is limited. Critical gaps include optimal thresholds, standardised protocols, and cost-effectiveness. Prospective validation across diverse populations and pathogens is essential before routine implementation.