Sinusitis

Odontogenic sinusitis (ODS) is increasingly recognized as a distinct form of sinonasal disease in which dental and sinus pathology coexist and frequently require coordinated management. Although systemic antibiotics are commonly prescribed, their precise role remains difficult to define because the available literature is heterogeneous and often extrapolated from studies of conventional rhinosinusitis or odontogenic infections. This review critically examines the evidence supporting systemic antibiotic use in ODS, with particular attention to clinical indications, microbiological considerations, therapeutic limitations, and their relationship with dental and sinonasal treatment. The polymicrobial nature of ODS, with frequent involvement of anaerobic organisms, provides a rationale for antimicrobial therapy in selected clinical circumstances. Antibiotics are particularly relevant in patients presenting with systemic manifestations, spreading or rapidly progressive infection, increased host vulnerability, or infectious complications, and may also be useful as temporary therapy when definitive intervention cannot be immediately performed. However, available evidence does not support routine antibiotic use solely on the basis of an ODS diagnosis or radiographic sinus abnormalities. In clinically stable patients with a treatable odontogenic condition, definitive dental treatment remains central to disease resolution, while persistent sinonasal disease may require endoscopic sinus surgery or other sinus-directed intervention. Repeated or progressively broader antibiotic courses in patients with persistent disease should prompt diagnostic and therapeutic reassessment rather than empirical escalation. Overall, systemic antibiotics retain an important but selective role in ODS management. Their use should be guided by the clinical presentation, severity of infection, host factors, and the feasibility of timely definitive treatment, while recognizing the limited direct evidence currently available.

Chronic rhinosinusitis (CRS) is common, but several rare diseases, rare sinonasal manifestations of systemic disorders, and uncommon local mimics can present as apparently refractory CRS. For terminology, this review uses the European epidemiological threshold of no more than 5 affected persons per 10,000 population for a rare disease, while conditions that do not consistently meet that threshold are described as uncommon mimics or rare sinonasal manifestations. The clinical problem is therefore not to test every patient for every rare disorder, but to recognise when routine CRS no longer explains the phenotype. This narrative review focuses on eosinophilic granulomatosis with polyangiitis (EGPA), granulomatosis with polyangiitis (GPA), primary ciliary dyskinesia (PCD), cystic fibrosis, humoral immune dysfunction, sarcoidosis, immunoglobulin G4-related disease, acute invasive fungal rhinosinusitis, sinonasal malignancy, and rhinolithiasis because they can mimic CRS yet require materially different investigation or treatment. A refractory course is not itself a diagnosis: symptoms should first be linked to objective sinonasal inflammation and treatment delivery assessed. Unilateral bleeding or a mass, tissue necrosis, facial numbness, visual or cranial neuropathy, destructive crusting, marked eosinophilia with adult-onset asthma, early-life wet cough with laterality abnormality, or recurrent bacterial respiratory infection should redirect investigation. Tests are most useful when interpreted conditionally, i.e., negative antineutrophil cytoplasmic antibody does not exclude localised vasculitis; nasal biopsy has limited sensitivity; low nasal nitric oxide is an adjunct rather than a stand-alone PCD diagnosis; and serum angiotensin-converting enzyme or immunoglobulin G4 cannot establish a tissue diagnosis. Cross-sectional imaging defines anatomy and extension but rarely determines aetiology without endoscopy and appropriately handled tissue. Biologic non-response should also trigger diagnostic reassessment before treatment escalation. The proposed red-flag framework is a pragmatic expert synthesis, not a validated diagnostic prediction rule, and is intended to facilitate earlier recognition of consequential mimics while reducing indiscriminate testing and serial empirical therapy.

Background: Hyperbaric oxygen therapy (HBOT) is proposed as an adjunct in two sinonasal conditions of high morbidity: acute invasive fungal rhinosinusitis (AIFRS) and post-radiotherapy injury. Methods: We conducted a narrative review and reported it against SANRA; PubMed/MEDLINE was searched (1980–2026; 1414 records screened, 589 retained), with Cochrane, society guidance and reference screening. Results: No randomised trial has tested HBOT against sinonasal endpoints in either indication. In AIFRS the dedicated evidence is four uncontrolled series (n = 27, level 4); none reports how many candidates were unfit to pressurise, the largest synthesis did not identify HBOT as a survival predictor, and the only randomised experiment—murine—was negative. Mycology guidance supports it with marginal strength only (C; quality III), and hyperbaric indication lists omit it. For radiation injury, Cochrane 2023 reports low-certainty benefit in head-and-neck tissue, but HOPON found no reduction in osteoradionecrosis after dentoalveolar surgery (6.4% vs. 5.7%; OR 1.13, 95% CI 0.14–8.92), and pooled DAHANCA-21/NWHHT2009-1 data were non-significant (70% vs. 51% healing); all sinonasal use is extrapolated from the mandible. Middle-ear, not sinus, barotrauma is the commonest ENT complication. Conclusions: HBOT is mechanistically coherent and may be considered case-by-case within a multidisciplinary team, but it is not a standard of care in either indication; the algorithm offered here is unvalidated.