The 10-day mark is a good way to diagnose not only acute rhinosinusitis but also adenoiditis, as confirmed by endoscopy

Objective: Acute rhinosinusitis (ARS) usually presents with respiratory complaints that persist for more than 10 days with no sign of improvement. This 10-day mark is considered to separate simple upper viral respiratory infection from ARS. Thus, the aim of the study was to evaluate a group of children with suspected ARS by performing nasal endoscopy. Methods: This cross-sectional study evaluated 287 consecutive children (152 males and 135 females, aged between 2 and 15 years), in whom ARS was suspected. A detailed clinical history was recorded for each patient and a thorough physical examination was carried out by an allergist-paediatrician. Patients were also evaluated by an ENT specialist who performed nasal endoscopy. Results: Endoscopy confirmed the clinical diagnosis of rhinosinusitis in 256 patients (89.2%). Isolated rhinosinusitis was diagnosed in 80.85% of cases (207 patients), whereas it was associated with adenoiditis in 49 (19.15%) children. Twenty patients had adenoiditis alone (7%). The distribution of the isolated and combined diagnoses differed significantly between age groups (p = 0.015), particularly between the youngest and oldest group (post hoc test p = 0.005). Conclusions: This study suggests that the endoscopy is a valuable tool in diagnosing children with suspected ARS and with adenoiditis too. Moreover, the age influences the diseases' pattern.