Children who take antibiotics at an early age are more likely to contract hay fever and skin eczema when they get older, a new study suggests.
Scientists from Utrecht University in the Netherlands reviewed massive medical databases — PubMed and Web of Science — in a search for observational studies from 1966 to 2015 linking antibiotic use in infants to toddlers aged two and the risk of eczema and hay fever. Eczema is a skin condition where the skin turns red, itchy and scaly, while hay fever is also known as allergic rhinitis. Both conditions are responses to allergens such as chemicals, pollen, dust mites, cat and dog hair and similar substances.
Fariba Ahmadizar, the lead researcher, noted that while there had been previous studies connecting early antibiotic use to an increase in allergies, the results were inconsistent, MedPage Today reports. They hoped to find more concrete answers.
Data from 44 studies involving over 650,000 patients with one or both conditions showed that the risk of eczema went up between 15 to 42% among those who had taken antibiotics before the age of two. The increase in hay fever risks showed a rise between 14 and 56% for the same set of individuals.
The authors noted that patients who had taken more than one course of antibiotics showed a stronger association in heightened risks for both rhinitis and eczema.
Antibiotics are believed to have properties that modify the immune system, and the researchers suggested that antibiotic use likely disrupts microorganisms in the gut, causing the hay fever and eczema associations.
Dr. Carla Davis, food allergy program director at Texas Children’s Hospital in Houston, told CBS News that while the study presented links between antibiotics and the two conditions, there are still many things to consider. She says, “We don’t know if the allergic disease caused increased amount of infections needing antibiotics, or if the antibiotics contributed to a change in the microbiome which may have influenced the development of allergic disease. Both of these explanations are plausible.”
The study was presented at the European Respiratory Society International Congress in London.