A: Anne, it’s good that you recognized your baby’s breathing difficulties and got him evaluated and treated promptly. Bronchiolitis is a respiratory infection involving swelling of the small airways (bronchioles) in the lungs, leading to difficulty breathing. It most commonly affects babies who are premature or have heart, lung or immune system problems, but it can also affect healthy infants. Viruses cause bronchiolitis, most commonly RSV (respiratory syncytial virus) in the winter months between October and March. Although RSV infection usually causes only a runny nose, mild cough and fever, progression to bronchiolitis leads to severe cough, fast breathing, grunting, wheezing and difficulty feeding. You may have also noticed a bluish tint around your baby’s mouth, indicating a lack of oxygen. If hospitalization is needed, treatment usually involves medications to open up the breathing tubes, oxygen and intravenous fluids. Sometimes anti-viral medication and mechanical ventilation is necessary.

Many children recover completely from bronchiolitis and never have another episode of wheezing again. But a recent study showed that infants hospitalized for bronchiolitis were more likely to develop wheezing and asthma later. The study compared a group of infants hospitalized for bronchiolitis with a group hospitalized for pneumonia and another “control” group that wasn’t hospitalized, and followed them until early adulthood. Over the years, they found that asthma was diagnosed in 30 percent of the children with bronchiolitis, compared with 15 percent of those with pneumonia and 11 percent of the controls. Some were diagnosed with asthma during childhood, but others not until early adulthood. Although children with bronchiolitis had two to three times the chance of developing asthma than the other children, the majority of children with bronchiolitis did not develop asthma.

Remember that there are other factors that can affect your baby’s chance of developing asthma. A family history of asthma and/or allergies and smoking increase the chance, while breastfeeding decreases the chance. To reduce your baby’s chance of developing asthma, breastfeed for a year or more and keep him away from cigarette smoke, especially in the house and car. When your child grows up, urge him not to smoke as well.