Think twice before slathering an infant’s scrape with Neosporin.

A new study from Yale researchers has found that early antibiotic exposure severely heightens the risk of developing childhood asthma. Published Dec. 29 on the American Journal of Epidemiology’s website, the results found that children who receive antibiotics within the first six months of age suffer a significantly higher risk of developing asthma and allergy by the time they turn six.

Antibiotics like penicillin and Neosporin, which are drugs used to treat bacterial infection, are regularly overused, some doctors said but cautioned that this finding might not be enough to reverse this trend.

“Antibiotics make an imbalance in the gut,” said Kari Risnes, lead author and Norwegian University of Science and Technology pediatrician. “It is necessary to have a broad spectrum of flora in the gut to stimulate a healthy immune system.”

The study, which included 1,401 children, shows that those exposed to antibiotics during their first six months of life are 52 percent more likely to develop childhood asthma and allergies than those who are not.

Unlike previous studies that have examined the link between general antibiotic use and childhood asthma, the present research focused on antibiotics used for reasons other than treating respiratory infections, which tend to signify a genetic predisposition to asthma, the paper said.

“Our main goal is to understand the causes of childhood asthma and how it should be treated,” said Michael Bracken, the principle investigator of the study and Yale professor of epidemiology.

Data collection for the study, which was conducted at the Yale Center for Prenatal, Pediatric and Environmental Epidemiology, began in 1997 with the recruitment of pregnant mothers. The mothers were interviewed about their child’s asthma status and exposure to antibiotics before the child’s birth, one month after, and within three months of the child’s sixth birthday.

The study contributes to a growing body of research indicating that early exposure to antibiotics increase risk of contracting asthma, said Dale Umetsu, professor of pediatrics at Harvard University and former director of the Center for Asthma and Allergic Disesases at Stanford University.

“Having more studies always helps to confirm if the idea of the ‘hygiene hypothesis’ is correct,” Umetsu explained, referring to the idea that a healthy immune system requires exposure to a diverse array of infectious organisms during childhood in order to develop properly.

For some children, antibiotics prove helpful and essential, Bracken said. But unnecessary use of antibiotics increases risk for childhood asthma and increases antibiotic resistance. Unfortunately, Bracken said, doctors tend to prescribe children antibiotics too quickly, leading to unforeseen consequences.

For this reason, it is prudent for mothers and pediatricians to exercise care in treating youngsters with antibiotics, Risnes and Bracken said.

“I believe pediatricians use antibiotics without effectively diagnosing illness,” said Dr. Alma Herrera, an asthma and allergy specialist at Adult and Pediatric Allergy Center in Mobile, Ala.

Even though Herrera said that for the past twenty years, it has been “common knowledge” among pediatricians that overusing antibiotics can lead to devastating effects, it is often difficult to convince parents that using antibiotics can do more harm than good, she said.

Herrera, a parent herself, said she doubted whether this study will be enough to convince parents about the harms of overusing antibiotics.

“It’s harder to not give antibiotics than to give antibiotics because you have to argue with parents; it’s time-consuming,” Herrera said.

But Umetsu argued that it is dangerous to say that people are overusing antibiotics because antibiotic treatment can be life-saving.

“The issue of when antibiotics are required depends on the situation,” he said.

One in four urban children in the developed world suffers from asthma, making it one of the most common chronic diseases of childhood.