The Role of Antibiotics in the Development of Atopic Diseases

Koniman, R; Van Bever, H P

Abstract

PURPOSE: This paper reviews the literature on antibiotics and allergic asthma, and comments on the association between antibiotic usage and the development of atopy, particularly allergic asthma. Possible theories or mechanisms about this association will be discussed.
METHODS
Articles in the English language were selected by an electronic search of the Medline OVID database from the year 1998 to 2006, with the key words:"antibiotics and asthma/atopy/allergy". The reference lists of the retrieved articles were then scanned for additional relevant publications. The main focus of this paper is to select articles that feature studies on this subject, particularly retrospective and prospective longitudinal studies.
RESULTS
We identified 9 retrospective and 3 prospective studies on postnatal antibiotic usage and allergy, 1 ecological study, 1 cross-sectional study, and 1 retrospective cohort study on prenatal antibiotic usage(i.e. in pregnant women). Despite all the retrospective studies finding a positive association between the use of antibiotics in early life and the subsequent development of asthma and/or atopy, the 3 prospective studies that suggested otherwise are more convincing due to the stronger study design. For those that found that there was an association, there were weaknesses to their study design and methodology, and the association is most plausibly explained by "reverse causation".
CONCLUSION
For those that maintained that there is indeed a causal relationship, it is worth remembering that allergic asthma is a complex syndrome possibly caused by the interaction of multiple factors, and is unlikely to be caused by one factor, such as the use of antibiotics. Also, should there be a causal link, the most plausible explanation is that antibiotics cause atopic disease by affecting the gut flora, rather than by directly affecting the immune system or by suppressing the effects of infections.