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What is Bronchiolitis?

PORTADAS WEB_bronquiolitis
Magda Gallardo Melero
Pediatric visits
16 Feb 2024
3 Min
The expert's voice
  • The bronchioles are the smallest airways in the lungs, responsible for transporting oxygen from the bronchi to the alveoli.


Bronchiolitis: Definition and Causes

Bronchiolitis is a viral infection that causes inflammation, irritation, and mucus buildup in the respiratory passages, leading to difficulty in breathing. It often affects infants under two years of age (babies and toddlers) because their smaller airways can easily become obstructed. It is common during the colder months, between November and April.

The infection can be caused by various viruses, with Respiratory Syncytial Virus (RSV) being the most common. Other viruses such as rhinovirus, influenza virus, or human metapneumovirus can also be responsible. The germs that cause bronchiolitis spread through droplets from the infected person’s nose and mouth, transmitted through the air via sneezing, coughing, or laughing, and can also be present on objects touched by the infected person (tissues, toys, etc.).

Risk factors that may increase the likelihood of an infant developing bronchiolitis include exposure to tobacco smoke, premature birth, direct contact with other children in daycare, pre-existing chronic lung or heart disease, or a weakened immune system due to illnesses or medications.

Symptoms of Bronchiolitis in Children

Bronchiolitis typically begins with symptoms similar to a common cold, including nasal congestion, fever or low-grade fever (below 38ºC), and cough.

Due to the blockage of the bronchioles by inflammation and mucus, the lungs receive a reduced amount of air, and additional symptoms such as fatigue and difficulty eating may appear after a few days.

The illness usually lasts between 7 and 10 days, but it’s important to be vigilant for certain symptoms that, if worsening, will require urgent medical attention from a pediatrician. These symptoms include:

  • Increased coughing.
  • Rapid, noisy, and wheezing breathing with difficulty (ribs may show, abdomen rises and falls excessively, and nostrils may flare).
  • Decreased appetite and reduced food intake.
  • Dehydration due to respiratory effort.
  • Vomiting after coughing.
  • High fever.
  • In rare cases, premature babies may experience brief pauses in breathing (apneas).
  • Severe fatigue.


In severe cases, symptoms can worsen quickly. If your child has difficulty breathing, and cough, retractions, or wheezing worsen, or if lips and fingertips turn blue (cyanosis), it is crucial to call the pediatrician immediately for evaluation and treatment.


When faced with bronchiolitis symptoms, the pediatrician will conduct a physical examination, listen with a stethoscope, and measure blood oxygen levels using pulse oximetry (a clip on the child’s finger), to determine the severity. In some cases, analyzing the child’s mucus may be done to identify the virus causing the infection. In cases of uncertainty, sudden deterioration, or severe cases, a chest X-ray may be necessary.


Fortunately, most cases of bronchiolitis are mild and do not require specific treatment. While there is no specific treatment for bronchiolitis, healthcare professionals may sometimes use  medications to relieve symptoms and help clear the child’s airways (never antibiotics, cough syrups, or mucolytics). Following the pediatrician’s instructions, it is recommended to:

  • Manage fever.
  • Keep the child well-hydrated by providing liquids and small amounts of food to prevent fatigue.
  • Perform frequent nasal washes and suction the nose secretions.
  • Keep the child in an “upright” position to help with breathing.


Babies having difficulty breathing, showing signs of dehydration, or appearing fatigued should always be evaluated by a doctor. In more severe cases, hospitalization may be necessary for close monitoring, and the child may receive fluids and humidified oxygen. In very severe cases, mechanical ventilation may be used until improvement is observed.


It’s essential to remember that adults and older children usually only exhibit symptoms of a common cold but can be highly contagious to young children. Therefore:

  • Avoid contact between the child and people with cold symptoms, and if unavoidable, have them wear a mask, cover their mouth with the elbow or sleeve when sneezing or coughing, and wash their hands thoroughly.
  • Try to avoid crowded places (public transportation, shopping malls, parties, etc.) during the peak virus months, especially if the child is very young (under 3 months) or premature.
  • Frequent handwashing with soap and water.
  • Avoid tobacco smoke at home and near children.
  • Ensure good ventilation in the house and the child’s sleeping area.
  • Regularly wash stuffed animals and toys.


In the face of bronchiolitis symptoms, the multidisciplinary team of pediatric specialists at CreuBlanca will evaluate your child’s case and symptoms, provide a diagnosis, and tailor a personalized treatment plan.

Hospital CreuBlanca Maresme offers outpatient pediatric consultations and 24-hour pediatric emergency care, 365 days a year, providing comprehensive care for your child from birth to adulthood, making them feel safe and cared for.