Children with a history of food allergy have a high risk of developing asthma and allergic rhinitis.
Children with a history of food allergy have a high risk of developing asthma and allergic rhinitis, a new US study has warned.
The risk increases with the number of food allergies a child might have, said researchers from The Children's Hospital of Philadelphia (CHOP).
"Eczema, asthma and allergic rhinitis are among the most common childhood medical conditions in the US," said lead researcher David A Hill, an allergy and immunology fellow.
The study is a retrospective analysis of the electronic health records of more than one million urban and suburban children in the CHOP Care Network from 2001 to 2015.
The researchers divided the records into two cohorts: a closed-birth cohort of 29,662 children, followed continuously for their first five years of life, and a cross-sectional cohort of 333,200 children and adolescents, followed for at least 12 months. The patients were 48 per cent white and 40 per cent black.
While prior studies have suggested patients with food allergies are at increased risk of developing asthma, those analyses were small and limited.
Allergies to peanut, milk, shellfish and soy were proportionately higher in the study population, while wheat allergy was proportionately rarer, and sesame allergy was higher than previously appreciated, researchers said.
Overall, children with existing food allergy were at increased risk of developing asthma and allergic rhinitis.
"For patients with an established diagnosis of food allergy, 35 per cent went on to develop asthma; and patients with multiple food allergies were at increased risk of developing asthma as compared to those with a single food allergy," said Jonathan Spergel, chief of the division of Allergy and Immunology at CHOP.
"Similarly, 35 per cent of patients with food allergy went on to develop allergic rhinitis," said Spergel. These asthma and allergic rhinitis rates in children with food allergy were roughly double the rates found in the general population, said researchers.
Allergic rhinitis, also known as hay fever, is a type of inflammation in the nose which occurs when the immune system overreacts to allergens in the air.
"Of the major food allergens, allergy to peanut, milk and egg significantly predisposed children to asthma and allergic rhinitis," added Hill.
The study was published in the journal BMC Pediatrics.