Grass pollen affects lung function in food allergic children
Published: April 7, 2022
It is well-known that grass pollen can trigger asthma and hay fever, but the risk of grass pollen-induced respiratory symptoms in children with other types of allergic conditions is unknown. It was theorized that at least for some of these children, grass pollen may trigger immune responses, resulting in lung function impairment.
Idrose et al. recently published a paper in The Journal of Allergy and Clinical Immunology: In Practice investigating the relationships between daily grass pollen concentrations and lung function changes in 6-year-old children from the HealthNuts cohort, and whether the impact of pollen was greater in those with allergic conditions such as asthma, hay fever, eczema and food allergy.
HealthNuts is an ongoing population-based study, that aims to investigate the burden of food allergy in children living in Melbourne, Australia. Commencing in 2007, a total of 5,276 1-year old children were recruited from immunization clinics. At 6 years of age, the participants were invited to undergo a clinic follow-up that included lung function measurements. Food allergy was determined by a positive oral food challenge (the gold standard for food allergy diagnosis) or well-documented recent reactions following food ingestion, while asthma, hay fever and eczema were determined using validated questionnaires, completed by parents of the children.
The authors found an increasing risk of asthma-like lung function deficits with increasing ambient grass pollen concentrations, especially in children with food allergy. Those with eczema, asthma and hay fever also experienced these changes, but to a lesser extent. This is probably because they already had poorer lung function, so the effect of an extra allergic challenge from ambient pollen may not be as sizeable, and/or they may have their conditions actively well-controlled (e.g. by using by asthma-preventive medications and/or by limiting time outdoors) during the grass pollen season. Additionally, the impacts of ambient grass pollen exposure on lung function impairment were consistently observed 2 days later in children with any allergic disease, and this is consistent with the known pathophysiology of induced allergic airway inflammation. If these findings are confirmed in further research, doctors can incorporate this knowledge into clinical practice so that children with food allergy and eczema are proactively managed for a potential asthma-type response during, and preferably before, high grass pollen periods. In the meantime, communication of warning messages about high pollen days should include families with children with ANY allergic symptoms, rather than just asthma or hay fever.
The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.