Detection of local allergic rhinitis in children with chronic, difficult-to-treat, non-allergic rhinitis using multiple nasal provocation tests

Background: There is little evidence on the incidence and characteristics of local allergic rhinitis (LAR) in children. Most studies have included subjects with perennial rhinitis only, and results are based on the investigation of no more than three allergens per study. Our aim was to determine the proportion of children with LAR amongst children with chronic, difficult-to-treat, perennial or seasonal, rhinitis but no evidence of sensitization to aeroallergens, or other alternative diagnosis. Methods: We performed multiple nasal provocation tests (M-NPTs) with four locally relevant aeroallergens (Phleum pratense, Olea europea, Alternaria alternata, and Dermatophagoides pteronyssinus) in children with absence of aeroallergen sensitization, seen during a calendar year in a specialized rhinitis clinic. We additionally performed single NPT to children with allergic rhinitis (AR; positive control group). The result of the NPT was based on symptoms and acoustic rhinometry. Identification of nasal hyper-reactivity (NHR) triggers was through a questionnaire. Results: Local allergic rhinitis was confirmed in 29.2% (7/24) of the negative SPT/blood testing population. All but one of the children reacted to one allergen and one to two. All AR children had positive single NPT with results similar to the LAR. There were no differences in age at examination and rhinitis onset, gender distribution, family atopy, and past or current environment of residency, while the prevalence of reported NHR triggers was comparable amongst the three groups. Conclusion: This is the first pediatric study where the seasonal or perennial rhinitis population was thoroughly tested for LAR against four aeroallergens. LAR is present in a considerable proportion of children with chronic, difficult-to-treat rhinitis and no sensitization to aeroallergens, and therefore, the performance of NPT should be strongly considered in these cases. There were no distinct clinical characteristics between LAR, AR, and non-allergic rhinitis in children.