The Role of Nasal Cytology in the Phenotyping and Monitoring of Chronic Rhinitis in Children.

Background: Local allergic rhinitis (LAR) is a rhinitis subtype characterised by an IgE-mediated response in the nasal mucosa. Although the nasal provocation test (NPT) is the diagnostic gold standard, it is impractical in many centres. Consequently, patients are often misclassified as having non-allergic rhinitis, delaying appropriate treatment. This study evaluated the role of nasal cytology in the classifying and monitoring paediatric allergic rhinitis (AR), distinguishing probable LAR (pLAR), and guiding treatment.

Methods: This retrospective study analysed data from 255 patients diagnosed with chronic rhinitis between March and June 2024. After applying exclusion criteria (recent allergy treatment, nasal deformities, incomplete records), 48 patients were included and grouped as pLAR (n = 11) or AR (n = 37). Nasal eosinophilia and atopy markers were assessed with clinical symptoms, before and after treatment.

Results: The mean age was 10.5 years (range: 3-17), with 64.6% male. AR was diagnosed in 77% and pLAR in 23%. Asthma was the most common comorbidity (37.5%). Persistent, moderate-severe symptoms were seen in 68.8%, with pollen sensitivity present in 76.3%. After treatment, both VAS scores and nasal eosinophil rates (NEOS%) significantly decreased in both groups (p < 0.05). NEOS% was higher in patients with atopic dermatitis and lower in those with adenoidal hypertrophy. AEC and NEOS% were positively correlated (p < 0.001), suggesting a link between systemic and local eosinophilia.

Conclusions: Patients with pLAR showed clinical and laboratory improvement similar to AR following treatment. Nasal cytology may be a useful diagnostic and monitoring tool in children with chronic rhinitis.