Nasal cytology in the diagnosis of allergic rhinitis in children

Background: Inflammatory cellular infiltrates of eosinophils and basophilic metachromatic cells are the hallmark of the atopic nasal responses in allergic rhinitis. Nasal cytologic examination for these cells not only establishes the diagnosis of allergic rhinitis but is also useful in the followup of patients with this condition. Objectives: To determine the usefulness of quantitative nasal cytology as an adjunctive diagnostic tool for children with allergic rhinitis in addition to history, physical examination and allergy skin testing. Materials and Methods: Forty-eight children with allergic rhinitis less than 15 years of age were recruited and evaluated for the following variables: symptoms and signs of allergic rhinitis, skin prick tests to common aeroallergens, paranasal sinus radiographs, and nasal cytology. Forty-one normal and healthy children less than 15 years of age served as controls. Nasal mucosal specimens were obtained by scraping the middle one-third of inferior turbinates with Rhinoprobes and were stained with Wright-Giemsa stain. Nasal cytology was examined under a light microscope and graded according to a previously suggested scoring system. Results: There were distinctive differences in the scores for nasal eosinophils and basophilic metachromatic cells between the allergic rhinitis and the control groups (P < .001). The sensitivity for nasal eosinophil scores or nasal basophilic metachromatic cell scores more than 0.5 in the diagnosis of allergic rhinitis was 91.7% with a specificity of 100%, positive predictive value of 100% and a negative predictive value of 91.1%. Presence of polymorphonuclear cells did not correlate with the presence of sinusitis as diagnosed by paranasal sinus radiographs. Nasal eosinophil scores correlated significantly with sign scores (P = .009). House dust mites were the most common allergens sensitized by this group of children (67.4% to 88.4%). Conclusion: Nasal cytology is a quick, simple, and inexpensive tool not only for the diagnosis of allergic rhinitis but also for serial evaluations of children with this condition as well.