Can Antibiotic Exposure Influence Development of Allergic Diseases?

A recent study provides certain implications for an association between exposure to antibiotics at a young age and the development of allergic diseases, primarily asthma, in early childhood.¹

            At some point, most people have gone to the doctor’s office and left with a prescription for an antibiotic. In today’s world, antibiotics have developed a connotation as a medicine that can ward off all sorts of sicknesses, which is only partially true. What many people don’t realize is that antibiotics are strictly useful for fighting bacterial infections and will have no effect on viral illnesses.* Although antibiotics have saved countless lives since the discovery of penicillin, there are some concerns about their use.

There two main negative consequences of using antibiotics more liberally than in the past: some unhealthy bacteria have increased resistance to treatment and administration of antibiotics can lead to decreased levels of healthy bacteria. The first consequence relates to overprescribing antibiotics for patients that may not be suffering from a bacterial infection. Every time a person takes antibiotics, he or she increases the likelihood that bacteria in the body will become resistant, which makes it difficult to treat later infections.^#

Commensal Bacteria

The second consequence, which directly relates to the study in question, has to do with the healthy bacteria that reside in the human gastrointestinal tract. When antibiotics are introduced to the body during infancy, a critical period for the development of the immune system, disruption to gut microflora can occur.¹ This could possibly predispose patients to the development of an allergic phenotype. Research shows that disruptions in the normal growth of gastrointestinal bacteria can prevent regulatory T cells from properly dampening the immune system’s response to respiratory allergens.^$  For more information, click here. Reduced diversity of microbes in infant excrement has also been connected to an increased risk of allergic diseases late in childhood.²

Allergic diseases develop when a person's immune system becomes sensitized to a normally harmless antigen. Type I hypersensitivity is a category of allergic reaction in which CD4+ Th2 cells that interact with these antigens stimulate B-cells to produce Immunoglobulin E (IgE) antibodies. These antibodies will then mark the specific antigen for destruction by other immune cells.⁺ Once the individual has been initially exposed and developed the specific antibodies, a subsequent exposure to the allergen will result in an allergic reaction. For more information, click here.

Mechanisms of Allergic Response