Assessing the onset of allergic rhinitis by nasal cytology and immunoglobulin E antibody levels in children.

Background: It is difficult to identify the onset of allergic rhinitis in infants because making a conclusive diagnosis can be challenging.

Objective: We used a combination of cell differentials in nasal swabs and immunoglobulin E (sIgE) antibody values to food and inhalant allergens to make the diagnosis and identify relevant allergens for investigation of the onset of allergic rhinitis.

Methods: We studied 302 children, 2 to 120 months old, who visited our clinic for rhinorrhea. Nasal swabs were taken from all children, and neutrophils (N), eosinophils (Eo), and mast cells (Mc) were identified by nasal cytology and their numbers were estimated. Levels of sIgE antibodies to various food and inhalant allergens were determined in patients with nasal Eo and Mc.

Results: Percentages of participants with Eo-Mc and Eo-Mc-N at 2-14 (n = 84), 15-24 (n = 57), 25-60 (n = 73), and 61-120 months of age (n = 88) were 20, 23, 58, and 65%, respectively. There were no significant differences between the 2-14 and 15-24, and 25-60 and 61-120 months age groups, but there was a significant difference between the 15-24 and 25-60 months age groups (p = 0.00013). The percentages of participants with sIgE antibodies to food and inhalant allergens as solitary or main allergen were 12%/0% at 2-14 months old, 10.5%/7% at 15-24 months old, 1.3%/42.4% at 25-60 months old, and 0%/56.8% at 61-120 months old, respectively with a significant difference between 15-24 and 25-60 months old groups (p = 0.00025) for inhalant allergens.

Conclusion: Allergic rhinitis associated with inhalant allergens in infants <15 months of age is rare, but it is tempting to postulate that symptoms of rhinitis in these infants may be associated with sIgE antibodies to food allergens. Transition of sIgE responses from food to inhalant allergens occurred after 15 months of age, and sIgE antibodies to inhalant allergens were predominant after 25 months.