Long implicated in numerous adverse events linked to intestinal immunity and associated mucosal tolerance a recent presentation at the American Academy of Allergy Asthma &Immunology annual meeting has shown a credible causation link between antibiotics and allergy.[1]
In their retrospective case–control study, presented as a late-breaking abstract at the meeting, Dr. Love and colleagues found an almost 2-fold increase in food allergy in children exposed to 3 or more courses of antibiotics between the ages of 7 and 12 months.
Systemic antibiotics not only kill bacteria causing an infection…[they] are also distributed to other parts of our body where they can kill susceptible bacteria that are part of our normal flora , the consequence can be increased reactivity to food antigens – or food allergy.
The investigators used South Carolina Medicaid billing data to identify more than 1100 children diagnosed with food allergy before the age of 3 and 6433 control subjects. They matched cases and controls by birth year, sex, and race.
Subjects in the 2 groups received a total 8046 courses of antibiotics, including penicillin (54%), cephalosporins (21%), macrolides (18%), and sulfonamides (7%).
The investigators controlled for asthma, atopic dermatitis, and eczema. “We know these patients tend to be more prone to food allergy,” Dr. Love said. “They’re also more likely to receive antibiotics, so we wanted to control for that.”
Logistic regression analysis showed that subjects with food allergy were more likely than control subjects to have received a course of antibiotics.
Table. Antibiotic Exposure Before 12 Months
| Outcome | Food Allergy Group | Control Group | P Value |
| At least 1 course of antibiotic | 77% | 66% | <.001 |
| Mean number of antibiotic courses | 2.65 | 1.84 | <.001 |
| Time to first antibiotic | 181.5 days | 190.1 days | .009 |
Table. Risk for Food Allergy With Antibiotic Exposure
| Antibiotic Exposure | Odds Ratio |
| Before 12 months | 1.71 |
| Between 0 and 6 months | 1.43 |
| Between 7 and 12 months | 1.98 |
| 3 courses | 1.45 |
| 4 courses | 1.60 |
| 5 courses | 2.15 |
Causation is not proven here, but indications based on this study and countless discussions with parents who note increased incidences of eczema and food allergy after antibiotics suggest that a relationship does exist.
Conclusions
Antibiotic exposure in the first year of life is associated with an increased risk of FA and may be a causal factor. Multiple courses confer a greater risk.
Reference
[1] Bryan L. Love, Joshua Mann, James W. Hardin, David Amrol, Antibiotic Exposure and the Risk of Food Allergy in Young Children. View Abstract
