Bronchiolitis is a viral infection that causes the bronchioles or airways in the lungs to swell, making breathing difficult. This is a frequent lung infection in infants and young children. The infection causes swelling, inflammation, and mucus buildup in the lung’s small airways.

Bronchiolitis symptoms typically last 1 to 2 weeks but can possibly continue longer. Children may experience breathing difficulties. Bronchiolitis usually begins with symptoms similar to a regular cold. However, it progresses and becomes more severe, resulting in coughing and a high-pitched whistling sound known as wheezing when exhaling.

Small children can spread bronchiolitis through personal contact, saliva, and mucous. The easiest method to avoid infection is to avoid people who are unwell and to wash their hands frequently.

Most children with bronchiolitis improve with home care. A small number of children require hospitalization.


Bronchiolitis symptoms are similar to those of a cold or flu. It may include:

  • Nasal congestion or runny nose
  • Cough
  • Mild fever (less than 101 F)
  • Breathing that is too fast or too shallow
  • Wheezing, which may occur 3 days or so after the onset first other symptoms

Many infants suffering from bronchiolitis also has an ear infection known as otitis media.

Some children may exhibit more severe symptoms, such as:

  • Making a grunting sound
  • Attempting to breathe so hard that their chest retracts
  • Having difficulty sucking and swallowing
  • Poor appetite and difficulty feeding
  • Lips, fingertips, or toes becoming blue or gray
  • Being sluggish

If any of these signs and symptoms are observed in children, it is essential to promptly contact a healthcare provider or take the child to an emergency room. This is especially critical if the baby is less than 12 weeks old or has additional risk factors for bronchiolitis, such as being born prematurely or having a heart disease.

This also applies especially if the child displays indications of dehydration, such as a parched mouth, infrequent urination, and crying without tears. Dehydration poses a significant risk to young children and should be treated as a serious matter.


Many bronchiolitis cases are caused by the respiratory syncytial virus (RSV), rhinovirus, and influenza (flu) virus. RSV is a common virus that affects nearly every child by the age of two. RSV outbreaks are common during the colder months of the year in some areas and the rainy season in others.

These viruses are highly infectious and are transmitted through direct contact with oral or nasal secretions, as well as through respiratory droplets in the air. When someone sneezes or coughs, these droplets are released into the atmosphere, facilitating their spread from person to person. Children can also get them by touching shared items like dishes, doorknobs, towels, or toys and then touching their eyes, nose, or mouth.

Risk factors

Bronchiolitis rarely affects adults. Infants younger than 3 months face the greatest susceptibility to bronchiolitis due to their underdeveloped lungs and limited immune defenses against infections. More often it affects children who are under 2 years old. Certain factors may also increase a child’s risk for bronchiolitis, such as:

  • Born prematurely.
  • Having a compromised immune system
  • Having a heart or lung disease
  • Exposure to many other children such as in a childcare facility
  • Spending time in congested areas
  • Being exposed to tobacco smoke
  • Having other people in the household who bring the virus home with them.