This article provides parents with a clear, medically informed overview of bronchiolitis caused by the Respiratory Syncytial Virus (RSV). You’ll learn how the virus spreads, the typical progression of symptoms in young children and infants, how doctors make a diagnosis, and what supportive care and monitoring at home and in the hospital involve.
Overview of RSV and Bronchiolitis
What Is RSV?
Respiratory Syncytial Virus (RSV) is a common viral pathogen that infects the lining of the upper and lower airways. In most older children and adults it causes mild cold-like symptoms. However, in infants and children under two years old, RSV frequently leads to inflammation of the smallest air passages (bronchioles), a condition known as bronchiolitis.
How RSV Spreads
RSV is highly contagious. It passes from person to person through:
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Direct contact with respiratory secretions (e.g., touching a contaminated toy then touching the nose or eyes)
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Respiratory droplets when an infected person coughs or sneezes
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Surface contamination, since RSV can survive on hard surfaces for several hours
Young infants are most vulnerable, especially if they have not yet built up any immunity or if they have underlying health issues.
Clinical Course, Diagnosis & Management
Incubation and Symptom Progression
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Incubation Period: Typically 4–6 days after RSV exposure.
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Initial Phase (Days 1–3): Starts like a common cold, with clear nasal discharge, mild cough, and low-grade fever. Appetite may decrease.
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Lower Airway Involvement (Days 3–6): As RSV reaches the bronchioles, inflammation and mucus plugs narrow the airways. This can lead to:
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Rapid, labored breathing (tachypnea)
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Flaring of the nostrils
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Chest wall retractions (visible sinking in of the skin between the ribs or above the collarbone)
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Wheezing or crackling sounds on breathing
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Increased work of breathing, possible oxygen desaturation
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About one in three infants will progress to moderate or severe respiratory distress, requiring medical evaluation for possible hospitalization.
Diagnosis of Bronchiolitis
Bronchiolitis is primarily a clinical diagnosis based on history and physical exam. Key elements include:
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Careful history: Onset of cold-like symptoms followed by worsening breathing difficulty
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Physical exam: Observation of breathing rate, work of breathing (retractions, nasal flaring), and auscultation for wheezes or crackles
Specific tests for RSV (nasal swab antigen test or PCR) may be done in severe cases or to guide isolation in a hospital setting. Blood tests and chest X-rays are generally unnecessary unless complications are suspected.
Supportive Care and Monitoring
There is no antiviral cure for RSV bronchiolitis; treatment focuses on supportive measures:
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Hydration: Encourage small, frequent feeds or breast-milk/formula feeds to prevent dehydration.
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Nasal clearance: Gentle suction of nasal secretions can ease breathing and feeding.
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Oxygen therapy: If oxygen saturation falls below safe thresholds, supplemental oxygen via nasal cannula may be needed.
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Hospital admission criteria: Include signs of dehydration (dry diapers, lethargy), significant breathing difficulty, or oxygen saturation consistently below 90–92%.
Mild cases can often be managed at home with close monitoring. Parents should watch for worsening respiratory effort, decreased feeding, or altered responsiveness.
Bronchiolitis in Infants: Symptoms, Complications & Recovery
Early Signs in Young Infants
Bronchiolitis often presents acutely in neonates:
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Initial cold-like phase—runny nose, occasional cough, mild fever for 1–2 days
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Onset of breathing difficulty—progressive rapid breathing, poor feeding, irritability
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Distinctive respiratory sounds—wheezing, crackles, prolonged exhalation, brief apnea episodes
Additional red-flag signs include:
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Persistent high fever (>38.5 °C)
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Marked pallor or bluish discoloration around lips (cyanosis)
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Refusal to feed or fewer wet diapers (sign of dehydration)
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Excessive sleepiness or inconsolable crying
Possible Complications
Though most infants recover fully within a week, bronchiolitis can lead to:
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Otitis media (middle ear infection)
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Secondary pneumonia
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Acute respiratory failure, requiring mechanical support
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Long-term sequelae, such as increased risk of wheezing or asthma later in childhood
Typical Duration and Prognosis
With appropriate supportive care, most children improve within 3–5 days. Some residual wheezing or cough may persist for 1–2 weeks as the airways heal. Full recovery is expected in the vast majority, with serious complications being the exception.
When to Seek Medical Help
Parents should contact their pediatrician or seek emergency care if the child shows any of the following:
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Rapid, struggling breathing with visible chest retractions
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Blue-gray tint around lips, face, or nails
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Refusal to take fluids for over 4 hours
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Lethargy or difficulty waking up
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Apnea episodes (pauses in breathing) in infants
Early recognition and prompt supportive treatment are key to ensuring a safe recovery from RSV bronchiolitis.
FAQ: How to treat viral bronchiolitis
Author: Antonino Francesco Capizzi. deadline Luglio 2025
Question: Does a specific treatment of the viral bronchiolitis exist?
Answer: Currently, a specific treatment does not exist. Sincitial Respiratory Virus (SRV) is the main responsible of this disease, a widely spread and contagious virus. Other viruses, such as rhinovirus, flu viruses and parainfluenza viruses, cause bronchiolitis as well. Therefore, sympthomatic and supportive therapy is necessary, aimed at alleviate the sympthoms and secure the proper patient hydration and breathing. The administration of antibiotics, steroids or anti-inflammatory drugs is not justified, unless a bacterial infection is detected.
Question: Why may some patients with bronchiolitis develop even severe forms of the disease, despite the initiated proceedings?
Answer: Viral bronchiolitis is a respiratory infection that predominantly affects the most distal airways (bronchioles) of newborns, infants and children under 2 years of age. It is transmitted airborne through respiratory or Flugge droplets infected with respiratory viruses, by direct and/or indirect contact with contaminated surfaces. Some groups of patients, due to their basal clinical characteristics, may be more vulnerable to severe forms and/or unresponsive to bronchiolitis treatment:
- premature infants;
- infants younger than 3 months of age;
- children with neurological disorders, chronic heart and/or lung diseases, immunodeficiencies.
In addition, there are the environmental and social factors that can increase the risk of contracting bronchiolitis in a severe form. These include secondhand smoke, lack of prolonged breastfeeding, air and environmental pollution, low caregiver compliance, and difficulties in accessing care.
Question: Given the diagnosis of bronchiolitis, what therapeutic measures can be implemented on the affected child?
Answer: First of all, the child suffering from bronchiolitis must be hydrated properly through the administration of frequent and non-abundant meals. Likewise, proper breathing should be encouraged by keeping the airways as pervious as possible. Nasal secretions should be suctioned gently, and nasal washes with saline should be practiced, several times a day and especially before meals. Such treatment can be given at home if the child maintains an adequate general clinical condition. In the event that the child needs to be hospitalized, fluid administration under continuous infusion therapy may be indicated and, in cases of severe respiratory distress, also oxygen therapy, either low-flow or high-flow, depending on the severity of the clinical picture.
Question: Is it possible to prevent the spread of viral bronchiolitis in the pediatric population?
Answer: To prevent the spread of SRV in the pediatric population, a specific vaccine has been available since 2024 and is free in Italy for pregnant women starting from the 28th week of gestation.
In addition, a drug consisting of a monoclonal antibody, called Nirsevimab, has been available in Italy since October 2024 and has contributed significantly to preventing the spread of SRV bronchiolitis. Passive immunization with a single dose of Nirsevimab is recommended for all newborns during the first season of exposure to SRV. A second immunization is also recommended during the second winter for children with increased susceptibility to the development of the severe forms of bronchiolitis and complications (such as dehydration, apnea, pneumonia, and acute respiratory failure). Among preventive interventions, using disposable tissues, avoiding smoking indoors or near the child, regularly sanitizing household surfaces and toys in contact with the little one, washing child’s and caregiver’s hands often, avoiding contact with people who are overtly affected by respiratory symptoms, and keeping the child away from crowded places during the months when respiratory viruses are most prevalent (October to March) are effective. It is very important to prevent pediatric bronchiolitis, as about 30% of affected patients have the risk of developing persistent wheezing and asthma in later ages.
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