Local allergic rhinitis in children: A systematic review

Background: Local allergic rhinitis (LAR) is a well-defined and reported phenotype in adults, but data is scarce for children and adolescents, and it is probably an undiagnosed and highly underestimated condition in childhood. Objectives: The objectives of this systematic review were to identify original observational studies published on LAR in children and adolescents and to describe the prevalence and characteristics of this phenotype in the pediatric age group. Methods: A systematic search was performed in PubMed and EMBASE databases. The search was limited to publications on humans, written in English, published between January 1, 2000 and September 20, 2021. Participants had to be under 18 years old and with a diagnosis of LAR confirmed by nasal allergen provocation test (NAPT). Results: Ten articles were identified. Despite the wide variability of protocols, prevalence rates ranged from 3.7 to 83.3% among children previously diagnosed as having nonallergic rhinitis, being markedly lower in Eastern countries (3.7–16.6%) when compared to Western countries (22.3–83.3%). To date, no relevant clinical characteristics capable of differentiating LAR patients from other childhood rhinitis phenotypes have been identified. Conclusions: LAR is an allergic rhinitis phenotype also found in children. Population and regional differences and differences in NAPT protocols may explain the heterogeneity in LAR prevalence rates observed in different parts of the world. In addition to clarifying this large discrepancy, longitudinal studies are also needed to assess the clinical characteristics of the LAR phenotype in the pediatric age group, and its stability into adulthood must be confirmed.