Clinic of Otorhinolaryngology, Head and Neck Surgery Unit, Department of Anesthesiology, Surgical and Emergency Science, University of Campania "Luigi Vanvitelli", Naples, Italy. Electronic address: [Email]
Allergic rhinitis (AR) is the most prevalent allergic disease in children and can be associated with asthma (A); this association can have significant effect on child's quality of life. The objective of this work was to systematically review existing literature on the risk factors of AR and A in children to better understand the link between these two diseases. We performed a literature search over the last 25 years in PubMed and Medline. Inclusion criteria comprised English language papers containing original human data with greater than 30 subjects and papers that statistically analyze the relationship between AR and A and the risk factor(s), in children population. A statistically significant correlation was found between children with AR and A and ambient Polycyclic Aromatic Hydrocarbons exposure, live in an industrialized city with elevated traffic, dampness and moulds exposure, electric cooking, male gender, single nucleotide polymorphisms in PTNP22 gene and CTLA-4 gene, fast food and margarine products consumption, use of paracetamol in last year, history of tuberculosis, parental atopy, high total serum IgE, antibiotics in uterus and infections in uterus exposure, history of formula feeding and caesarian section. A strong and complex link between AR and A was accounted: A represents a major risk factor for the onset of AR, that correlates with more severe asthmatic symptoms. Even the onset of A in a child with AR worsen it. The interaction of genetic and environmental risk factors and the consequent epigenetic, microbiota and immunological changes, were found to led to the development of AR and A in children, with both atopic and non-atopic pathways. Close monitoring of evidenced risk factors may help with an early recognize and treat A in patients with AR.