Bronchiolitis is a common respiratory infection that affects babies and young children. It occurs when the smallest airways in the lungs, called the bronchioles, become infected and inflamed, leading to a build-up of mucus. This makes it harder for the child to breathe because the amount of air entering the lungs is reduced.
It is estimated that a third of infants in the UK develop bronchiolitis in their first year of life, and 90% of those who do are less than nine months old. This is because babies have smaller airways, and their lungs and immune systems may not yet be fully developed. Premature babies, those born with lung or heart diseases, and those with weakened immune systems are most at risk of the condition, and may need special care if they develop it.
Bronchiolitis is most commonly caused by an airborne virus called respiratory syncytial virus (RSV), which is passed on through direct contact and through airborne droplets spread by coughing and sneezing. The condition usually occurs in winter.
Many of the symptoms of mild bronchiolitis are similar to those of a common cold, including a stuffy nose, mild fever and a cough. There is no medicine that can kill the virus, but the infection usually clears up on its own, and treatments can be used to make children more comfortable. In more severe cases, children may need to be hospitalised if they are having difficulty breathing or are refusing to eat and drink.
