Bronchiolitis

Bronchiolitis is a common lung infection that affects babies and young children, causing inflammation and mucus buildup in the tiny airways of the lungs, which can make breathing difficult.

Table of contents

• What is bronchiolitis?
• What causes bronchiolitis?
• Who gets bronchiolitis?
• Signs and symptoms
• When to see a doctor
• How is it diagnosed?
• Treatment and care
• Prevention
• What to expect

What is bronchiolitis?

Bronchiolitis is an infection of the small airways in the lungs called bronchioles (tiny breathing tubes that branch off from the larger airways). When a baby has bronchiolitis, these small airways become swollen and filled with mucus, which blocks the flow of air and makes breathing difficult^[1][2].

This condition is most common in babies and young children, especially those under 2 years of age. It is the leading cause of hospital admission in infants under 1 year old^[4][7]. For most children, bronchiolitis is a mild illness that gets better on its own with care at home. However, some babies may need hospital care if they have trouble breathing or feeding^[3].

• Bronchioles (small airways in the lungs)
• Lungs
• Respiratory tract

What causes bronchiolitis?

Bronchiolitis is caused by viruses. The most common virus that causes bronchiolitis is respiratory syncytial virus (RSV), which accounts for about 75% of cases in children younger than 2 years who need hospital care^[2][7].

Other viruses that can cause bronchiolitis include^[2][7]:

• Human rhinovirus (the virus that causes the common cold)
• Coronavirus
• Human metapneumovirus
• Adenovirus
• Parainfluenza virus
• Human bocavirus
• Influenza (flu) virus

In about 30% of cases, two or more viruses may be present at the same time^[2][7].

The viruses that cause bronchiolitis are very contagious. They spread from person to person through tiny droplets in the air when an infected person talks, coughs, or sneezes. These droplets can be breathed in by others or can land on surfaces that people touch^[3][10].

Who gets bronchiolitis?

Bronchiolitis most commonly affects children under 2 years of age, with peak incidence in infants aged 3 to 6 months^[7]. During the first year of life, about 11% to 15% of children will develop bronchiolitis^[2].

The infection is seasonal and usually occurs during autumn and winter months. In the northern hemisphere, most cases happen from December to February^[7].

Some children are at higher risk of getting severe bronchiolitis. Risk factors include^[2][4][10]:

• Being younger than 3 to 5 months old
• Being born prematurely (before 32 to 34 weeks of pregnancy)
• Having a congenital heart disease (heart problems present at birth)
• Having chronic lung disease (such as bronchopulmonary dysplasia)
• Having a weakened immune system
• Having neuromuscular disease
• Exposure to tobacco smoke, especially if the mother smoked during pregnancy
• Living in crowded conditions or attending daycare
• Being from a low socioeconomic background
• Being Aboriginal or Torres Strait Islander^[3]

Signs and symptoms

Bronchiolitis usually starts with symptoms that are much like a common cold^[1][3]:

• Runny nose
• Stuffy or blocked nose
• Sneezing
• Mild cough
• Sometimes a slight fever (under 38°C or 101°F)
• Sore throat

After one or two days, the symptoms can get worse. The cough tends to worsen, and breathing becomes harder^[3][8]. Common symptoms at this stage include^[1][3][10]:

• Fast or rapid breathing
• Wheezing (a high-pitched whistling sound when breathing out)
• Breathing that looks like hard work (you may see the ribs or skin under the neck pulling in with each breath, or the nostrils flaring)
• Younger babies may bob their heads when breathing
• Acting unsettled, restless, fussy, or irritable
• Trouble eating and drinking due to difficulty breathing
• Grunting noises when breathing

Symptoms are usually worst on the second or third day, and most babies are sick for around 7 to 10 days. The cough may continue for up to 4 weeks after the illness^[3][6].

Many infants with bronchiolitis also develop an ear infection^[1].

When to see a doctor

You should see a doctor or other health professional if you think your baby has bronchiolitis^[6].

Call your child’s healthcare provider if your child^[1][6]:

• Develops a new or high fever
• Has a cough or other symptoms that get worse
• Is wheezing
• Has heart disease or was born prematurely

Get medical care right away if your child^[6][8]:

• Has trouble breathing, with fast, shallow breathing or is working hard to get breaths in
• Shows areas below the ribs, between the ribs, or in the neck sinking in with breathing
• Has flaring nostrils
• Has lips or fingernails that look blue, gray, or pale (cyanosis)
• Is very fussy and cannot be comforted
• Is very tired or won’t wake up for feedings
• Is not feeding well or shows signs of dehydration, such as fewer wet diapers than usual, dry mouth, or crying without tears
• Stops breathing briefly (apnea)
• Makes grunting noises with each breath or cannot speak or cry because of struggling to breathe

How is it diagnosed?

A doctor can usually diagnose bronchiolitis by examining your child and reviewing their symptoms^[3][6]. The doctor will listen to your child’s lungs with a stethoscope and check their breathing^[9].

Tests and X-rays are not usually needed to diagnose bronchiolitis^[9]. However, your child’s doctor may recommend tests if your child is at risk of severe bronchiolitis, if symptoms are getting worse, or if the doctor thinks there may be another problem. Tests may include^[4][9]:

• Pulse oximetry: A sensor is placed on a finger or toe to measure the oxygen level in the blood
• Viral testing: A sample of mucus from your child’s nose can be tested to identify the virus causing the infection. This is done using a swab that is gently inserted into the nose
• Chest X-ray: This may be done if your child’s oxygen level is low or the doctor suspects pneumonia
• Blood tests: Occasionally, blood tests might be used to check your child’s white blood cell count or oxygen level

The doctor may also look for signs of dehydration, such as dry mouth and skin, extreme tiredness, and making little or no urine^[9].

Treatment and care

There is no specific medicine to treat bronchiolitis because it is caused by a virus^[2][14]. Antibiotics do not work against viruses and are not used unless there is also a bacterial infection^[9]. Most children with bronchiolitis can be cared for at home with supportive care^[3][9].

Home care

Home treatment focuses on managing symptoms and keeping your child comfortable^[6][9]:

• Fluids: Give your child plenty of liquids to prevent dehydration. Offer frequent small feedings of clear fluids. For babies, continue breastfeeding or bottle feeding
• Clear the nose: Use a suction bulb or nasal aspirator to remove mucus from your baby’s nose, especially before feeding and sleeping. Use nasal saline drops to help thin the mucus
• Humidity: Use a cool-mist humidifier or let your child breathe steamy air from a warm shower to help thin the mucus and make it easier to clear
• Fever relief: Give fever medicine such as acetaminophen or ibuprofen if needed to reduce fever and discomfort. Never give aspirin to anyone younger than 20 because of the risk of a serious illness called Reye syndrome
• Rest: Make sure your child gets plenty of rest
• Upright position: Keeping your baby in a slightly upright position may help with breathing and feeding

Over-the-counter cough and cold medicines are not recommended for young children^[6].

Hospital care

Some children need to be hospitalized if they have severe bronchiolitis. In the hospital, treatment may include^[8][9]:

• Oxygen therapy: Extra oxygen is given through a nasal tube, mask, or oxygen tent if the child’s oxygen level is low
• Fluids by vein: If the child cannot drink enough fluids by mouth, fluids may be given through an intravenous (IV) line
• Deep suctioning: Healthcare providers may use special equipment to suction mucus from deep in the airways
• Monitoring: Oxygen levels and breathing are closely monitored

In very severe cases, a child may need help with breathing through a ventilator (breathing machine)^[2].

Research has shown that many treatments once commonly used for bronchiolitis, such as bronchodilators (albuterol), corticosteroids, and chest physiotherapy, do not help and are no longer recommended^[12][14]. Some studies suggest that nebulized hypertonic saline (a saltwater solution) may help reduce hospital stay when given with a bronchodilator, but more research is needed^[12][14].

Prevention

Because the viruses that cause bronchiolitis are very contagious, preventing the spread of infection is important^[3][6]:

• Hand washing: Wash your hands often with soap and water, especially before touching your baby or preparing food. This is one of the most effective ways to prevent the spread of germs
• Avoid contact with sick people: Keep your baby away from people who have colds or other respiratory infections
• Keep sick children home: If your child has bronchiolitis, keep them home from daycare or school until they get better
• Do not smoke: Never smoke or use other tobacco products around your child. Secondhand smoke irritates the airways and increases the risk of respiratory infections. Exposure to tobacco smoke can also make bronchiolitis worse
• Clean surfaces: Clean and disinfect frequently touched surfaces and objects

RSV immunization

Immunization against RSV can help protect young babies from severe bronchiolitis. In some countries, there are programs that offer RSV vaccination for pregnant women and immunization for babies. Both products are very effective at preventing babies from needing hospital care with RSV^[3].

For high-risk infants (such as premature babies or those with heart or lung disease), preventive medicines may be available. These include RSV immunoglobulin or the anti-RSV monoclonal antibody called palivizumab, which can help decrease disease severity^[2][6].

Talk to your doctor about whether your baby should receive RSV immunization or preventive medicine.

What to expect

For most children, bronchiolitis is a mild, self-limiting illness that gets better on its own within 1 to 2 weeks^[6][9]. The cough may persist for up to 4 weeks after the acute illness^[3][4].

Symptoms are usually worst during the first 5 days, particularly on the second or third day^[3][6]. After this peak period, most children begin to improve gradually.

While most cases are mild, bronchiolitis can sometimes progress to respiratory failure in infants, especially in those with risk factors^[2]. Depending on the severity of the infection, about 5 hospitalizations occur for every 1,000 children younger than 2 years of age^[2].

Some children who have had bronchiolitis may go on to develop recurrent wheezing or asthma later in childhood^[4][10]. However, many children recover completely without long-term problems.

If you have concerns about your child’s recovery or if symptoms are not improving, contact your child’s healthcare provider for guidance.