Bronchiolitis – Symptoms and Causes

Overview

Bronchiolitis affects the small airways (bronchioles) in a child’s lungs. It causes inflammation, swelling, and mucus buildup. This respiratory infection almost always comes from viral causes.

The illness typically begins with cold-like symptoms. Then, it progresses to more serious issues like:

• Persistent coughing
• Wheezing (high-pitched whistling sound during exhalation)
• Breathing difficulties in some cases

Most children recover with proper home care within 1-2 weeks, though symptoms occasionally persist longer. While most cases don’t require hospitalization, some children—particularly those with severe symptoms—may need hospital treatment.

Symptoms

Early signs of bronchiolitis often look like a common cold. Children typically experience:

• Runny nose
• Stuffed-up nose
• Coughing
• Mild fever (in some cases)

After these initial cold-like symptoms, your child might have more serious breathing difficulties that last a week or longer. Wheezing sounds—a high-pitched whistling noise when breathing out—may also develop.

Many young children with bronchiolitis also develop middle ear infections at the same time.

When to Get Medical Help

Contact your child’s healthcare provider if symptoms become severe. This is especially important for babies under 3 months old or children with risk factors like premature birth or heart conditions.

Seek immediate medical attention if your child shows any of these warning signs:

• Bluish or grayish color in the skin, lips, or fingernails
• Severe breathing difficulty that prevents crying or speaking
• Poor feeding due to rapid breathing
• Very fast breathing (more than 60 breaths per minute in infants)
• Shallow, short breaths
• Visible inward pulling of the ribs or chest with each breath
• Wheezing sounds during breathing
• Grunting noises while breathing
• Unusual lethargy, weakness, or fatigue

These symptoms could indicate your child isn’t getting enough oxygen and needs prompt medical care.

What Causes Bronchiolitis

Bronchiolitis occurs when viruses infect the bronchioles, the smallest air passages in the lungs. These tiny airways become inflamed and swollen due to the infection.

As mucus builds up in these passages, breathing becomes difficult because air cannot flow easily through the lungs.

The respiratory syncytial virus (RSV) is the most common cause of bronchiolitis. Almost all children contract RSV by age 2.

RSV outbreaks typically happen during cold months in some areas or rainy seasons in others. People can get RSV multiple times throughout their lives.

Other viruses can also cause bronchiolitis, including:

• Common cold viruses
• Influenza (flu) viruses

These viruses spread easily from person to person through:

• Airborne droplets when infected people cough, sneeze, or talk
• Direct contact with contaminated surfaces or objects
• Touch transmission when people touch shared items (toys, doorknobs, dishes) and then touch their face

The infection risk is higher in crowded places where viruses can quickly pass between people. Young children often spread these viruses easily because they frequently touch their faces and share toys without washing their hands.

Risk Factors

Children under 2 years old can get bronchiolitis, with babies younger than 3 months facing the highest risk because their lungs are still developing and they cannot fight infections well. Adults rarely get this illness.

Several factors increase a child’s risk:

• Premature birth
• Existing heart or lung problems
• Weakened immune system
• Exposure to tobacco smoke
• Attending child care centers
• Being in crowded environments
• Having brothers or sisters who attend school or daycare

For babies with certain health conditions, the illness can be more serious.

Complications

Severe bronchiolitis can lead to several serious health problems. These include:

• Oxygen deficiency in the body
• Breathing pauses (apnea), especially in premature babies and infants under 2 months
• Dehydration from difficulty drinking fluids
• Respiratory failure when the body can’t get enough oxygen

These complications often require hospital care. A child may need monitoring and treatment to maintain proper oxygen levels and hydration.

In very serious cases of respiratory failure, healthcare providers might insert a breathing tube into the child’s windpipe. This tube helps the child breathe properly until their body can fight off the infection.

Parents should watch for signs of worsening symptoms and seek medical help promptly if their child’s condition deteriorates.

Preventing Bronchiolitis

Preventing bronchiolitis involves simple steps that can reduce the risk of infection. Since the viruses that cause this condition spread from person to person, good hygiene and certain protective measures are essential.

Protecting Your Child

Washing your hands often is one of the best ways to prevent bronchiolitis. This is particularly important before touching your baby if you have a cold, flu, or other contagious illness.

Consider wearing a face mask if you are sick but need to care for your child. If your child has bronchiolitis, keep them home until they recover to avoid spreading the illness to others.

Here are important prevention strategies:

• Avoid Sick Contacts: Keep your baby, especially newborns and premature infants, away from people with fevers or colds. This is crucial during their first two months.

• Clean Frequently: Disinfect surfaces and items that people touch often, such as toys and doorknobs. This becomes even more important when someone in your household is sick.

• Practice Good Hand hygiene: Wash hands thoroughly with soap and water for at least 20 seconds. Carry alcohol-based hand sanitizer (at least 60% alcohol) when away from home.

• Cover When Coughing or Sneezing: Use a tissue and throw it away after use. Then wash your hands. If you don’t have a tissue, cough or sneeze into your elbow instead of your hands.

• Use Separate Drinking Glasses: Don’t share glasses, especially when someone in your family is sick.

• Consider Breastfeeding: Breastfed babies typically have fewer respiratory infections.

Immunizations and Protective Measures

Respiratory syncytial virus (RSV) is the most common cause of bronchiolitis in infants under one year in the United States. Two immunization options can help protect young babies from severe RSV illness. These are recommended by leading medical organizations.

Talk with your healthcare provider about which option might be best for your child:

1. Single-Dose Protective Antibody (Nirsevimab): This is given as one shot before or during RSV season for:
   • Newborns and babies younger than 8 months entering their first RSV season
   • Children 8-19 months who have higher risk factors and are entering their second RSV season

2. Vaccine for Pregnant Women: A single-dose RSV vaccine can be given between 32–36 weeks of pregnancy during September through January. This helps protect newborns from birth through 6 months of age.

In rare cases, a different product requiring monthly injections may be used for high-risk children when the standard antibody isn’t available.

Other viruses like COVID-19 and influenza can also cause bronchiolitis. Everyone over 6 months old should receive yearly COVID-19 and flu vaccinations to provide additional protection.