Antibiotics and Asthma

Your baby is sick with a cold. The coughing and sniffling has made it difficult for anyone in the house to get a good night’s sleep. Your doctor examines your baby and confirms there is no ear infection and no sign of pneumonia. This is an acute respiratory infection caused by a viral infection that is best treated with rest, fluids, and time. “But Doctor,” you ask, “aren’t you going to prescribe antibiotics?”

Antibiotics are powerful medications that have saved numerous lives, but antibiotics are only effective against bacteria, not the viruses that cause common colds and most ear infections. For years there has been growing concern in the healthcare community about the super strains of resistant bacteria developing from the overuse of antibiotics. More recently, a new concern has emerged – antibiotic use in childhood and the development of asthma.

The human GI tract contains 1 trillion bacteria. These ‘good’ bacteria are critical for digestion and the development of the normal immune system. Antibiotics kill both the disease-causing bacteria and the good bacteria which can throw off the delicate balance that exists in the gut. If this antibiotic triggered imbalance occurs during infancy, when the immune system is developing, it may encourage the later development of asthma and other allergic conditions. This idea of the hygiene hypothesis has been present for several decades and used to explain why children growing up on farms have lower incidence of asthma and allergic disease.

A number of research studies have looked at this issue with mixed, but concerning, results. In 2006, a compilation of all the previous research on this topic reported that antibiotics in the first year of life were associated with a doubling of the risk of childhood asthma. A subsequent study showed a 46% increase in asthma in children receiving 4 courses of antibiotics in their first year. A 2014 study of over 62,000 children associated an increase in childhood asthma with antibiotic exposure in infancy. These findings have also been duplicated in mice showing increased food allergy and asthma in the mice who received antibiotics. A study from Sweden in 2014 failed to show an association between antibiotics and the later development of asthma.

Researchers will continue to study this issue and other aspects of the developing immune system such as the effect of probiotics, fatty foods, vitamin D and pollution. In the meantime, it is important to carefully consider the use of antibiotics in your children and other members of your family. Be sure to ask your doctor about all the options available to treat your child’s illnesses and whether antibiotics are a necessary part of the treatment plan.