In a new paper Dharmage, University of Melbourne review the data on this issue. They summarise their conclusions as follows:
While epidemiological and other studies suggest a link between antibiotic exposure and asthma and allergies, findings to date do not provide conclusive evidence for a causal link. The link between antibiotics and asthma and allergies requires further investigation either to confirm or refute. To date, researchers have either analysed existing data within longitudinal studies or used registry-based data. Both approaches suffer from a lack of comprehensive information with which to tease out confounding by indication. Since it is not feasible to conduct randomised controlled trials, population-based longitudinal studies specifically designed to answer this particular question are needed to resolve the debate.
If this link is established, including understanding which specific classes of antibiotics are implicated, it provides a plausible mechanism concerning the aetiology of asthma and the allergy epidemic and will inform clinical guidelines on prescription of antibiotics.
As evidence mounts concerning antibiotics and their potential role in allergy promotion through disturbance of the gut microbiome and subsequent impairment of immune programming in young children, there is increasing interest in the potential role of pre- and probiotics for treatment and prevention of allergic diseases.
The paper can be found in: Clinical & Experimental Allergy, 2014; 45, 6–8