Local allergic rhinitis in children: clinical characteristics and role of basophil activation test as a diagnostic tool.

Background Local allergic rhinitis (LAR) is a condition involving a localized nasal allergic response in absence of systemic atopy. We aimed to describe clinical characteristics of LAR and non-allergic rhinitis (NAR) pediatric patients, their clinical evolution over a 7-year follow-up period and to study the role of basophil activation test (BAT), for the diagnosis of LAR. Methods Forty-four children with non-allergic rhinitis (NAR) were included (24 males, 20 females, aged under 15 years). Nasal allergen provocation test (NAPT) and BAT were performed with Dermatophagoides pteronyssinus and Phleum pratense. Results Seven patients (16%) were diagnosed of LAR. Seven reacted to D pteronyssinus and one also to P pratense. All LAR and 86% of NAR patients presented perennial symptoms. Fifty-seven percent of NAR and LAR patients referred persistent symptoms. Three LAR patients associated conjunctival symptoms. BAT was positive after stimulation with D pteronyssinus only in one LAR patient. On follow-up, 3 LAR patients and 10 of the 25 NAR patients who agreed to be retested, presented systemic sensitization. Conclusions LAR should be considered in children with NAR. Almost half of children with LAR and one fourth of NAR children will develop systemic sensitization over time. BAT shows low sensitivity for the diagnosis of LAR in children. Key message: Since sixteen percent of initially diagnosed as non-allergic rhinitis children present local allergic rhinitis, we suggest performance of nasal provocation test in those cases to achieve a correct diagnosis. Basophil activation test seems to be less sensitive for the diagnosis of local allergic rhinitis in children than in adults. Follow up over would be interesting since a significant number local allergic rhinitis children and non-allergic rhinitis children will eventually develop systemic sensitization to aeroallergens.