What is bronchiolitis?
Bronchiolitis is when the smallest air passages in a child's lungs become swollen. This can make it more difficult for your child to breathe.
Usually, bronchiolitis is caused by a virus called respiratory syncytial virus (known as RSV). Almost all children will have had an infection caused by RSV by the time they are two years old. It is most common in the winter months and usually only causes mild "cold-like" symptoms.
Most children get better on their own.
Some children, especially very young ones, can have difficulty with breathing or feeding and may need to go into hospital.
Most children with bronchiolitis get better within about two weeks but the cough may go on longer.