Results of a US study suggest that the presence of certain respiratory conditions in early infancy is associated with allergic disease and asthma risk when children reach school age.
Writing in the Journal of Allergy and Clinical Immunology, Dr Clare Ramsey, from Brigham and Women’s Hospital in Boston Massachusetts, and team explain: “The relation between respiratory infectious illnesses in early life and asthma in childhood is incompletely understood.”
To address this, the researchers studied the incidence of respiratory diseases in the first year of life among 440 children who were born between 1994 and 1996 to parents with a history of allergic disease.
The children were monitored until they were 7 years of age and all cases of wheezing, allergic disease and diagnosed asthma and hayfever (allergic rhinitis) were recorded.
The team found that children diagnosed with bronchiolitis (inflammation of the small airways) before 1 year of age were 2.8 times more likely to develop asthma in later life than those who were not.
In addition, more than three recurring episodes of a runny nose in the first year of life were associated with a three-fold increased risk of hayfever by 7 years of age.
However, a diagnosis of croup, characterised by harsh coughing, hoarseness, fever and breathing difficulties, and ear infections in early life appeared to be associated with a significantly reduced risk of allergic disease at the age of 7 years.
“Certain respiratory illnesses in early life modify the risk of atopy [allergic disease] and asthma at school age,” Dr Ramsey and colleagues summarise.
They conclude: “The relationship between early-life respiratory illnesses and asthma and atopy is complex and likely dependent on the type of infection and immune response it initiates.”