Croup and respiratory syncytial virus (RSV) are related conditions. RSV is one of the common causes of croup in children.

Respiratory syncytial virus (RSV) causes lung and respiratory tract infections. In healthy adults and older children, it typically leads to mild, cold-like symptoms, such as coughing, sneezing, and fever. However, RSV can lead to more serious conditions, such as bronchiolitis and pneumonia, in infants, young children, and older adults.

Croup is characterized by a distinctive barking cough, hoarseness, difficulty breathing, and stridor — a harsh, grating sound when inhaling. Croup is primarily the result of viral infections that lead to swelling of the larynx (voice box), trachea (windpipe), and bronchi (large air passages leading to the lungs). Various viruses can cause croup, including RSV.

This article looks at the connection between croup and RSV. It explains their similarities and differences and goes over their risk factors, treatment, and prevention.

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The connection between RSV and croup lies in the pathophysiology of the diseases. An RSV infection of the respiratory system can cause inflammation and swelling of the airways, which can narrow the larynx and trachea. This can lead to the classic symptoms of croup, including a barking cough and stridor.

RSV is not always the cause of croup. Other viruses, including the parainfluenza virus, also commonly cause croup. However, during RSV season, which typically peaks in the fall and winter months, there is often an increase in cases of croup among children.

Learn more about RSV.

RSV refers to an infection that can lead to a range of symptoms, such as:

  • coughing
  • sneezing
  • runny nose
  • fever
  • decreased appetite
  • wheezing

It can also lead to severe infections, such as bronchiolitis and pneumonia. It is the most common cause of these conditions in children under 1 year of age.

Croup is a common respiratory illness that can be the result of RSV. Symptoms of croup include a distinctive barking cough, stridor, and hoarseness. These symptoms are generally due to swelling of the larynx, trachea, and bronchi.

RSV infections primarily affect the lower respiratory tract — lungs and bronchioles. Croup usually affects the upper respiratory tract, specifically the larynx, and trachea, leading to its characteristic symptoms.

Learn more about croup.

Both RSV and croup predominantly affect young children. However, the risk factors for each condition can vary.

Some people may be at a higher risk for RSV than others. These groups may include:

  • older adults over the age of 65
  • infants up to 1 year old, especially those under 6 months
  • infants born prematurely
  • those with compromised immune systems
  • people with chronic lung conditions or congenital heart disease

Croup is most common in children between 6 months and 3 years of age. Most times, it occurs in children around 1 year of age. It can also occur in infants as young as 3 months and older children up to 15 years old. Rarely, adults can also develop croup.

Treatment for RSV focuses on symptom management and support. Most people with RSV can treat it at home with over-the-counter (OTC) fever reducers and pain relievers. People with severe cases may require hospitalization for supplemental oxygen or mechanical ventilation.

Croup is often treatable at home. Children generally recover from it within 3–4 days with at-home care, which may include:

  • plenty of fluids
  • rest
  • using a humidifier or steaming the bathroom up with the shower

People with more severe cases may require medical treatment, including corticosteroids, hospitalization, epinephrine, and oxygen.

Read more about home treatments for croup.

Both RSV and croup benefit from general preventive measures to reduce the spread of respiratory viruses. These include:

  • maintaining proper hygiene practices, such as regularly washing the hands
  • avoiding close contact with unwell people
  • considering using masks during peak viral seasons, especially in settings where viral transmission is likely, such as day care centers or public gatherings

The Centers for Disease Control and Prevention (CDC) also recommends an RSV vaccine for adults over the age of 60 and people who are between 32 and 36 weeks of pregnancy. Infants between 8 and 19 months can also receive a preventive antibody to help prevent RSV.

Certain vaccinations can also help prevent some viruses that can cause croup in children. The MMR vaccine can help prevent mumps, measles, and rubella. The DTaP/IPV/Hib vaccine can help prevent tetanus, diphtheria, whooping cough, and polio, among others.

Implementing these preventive measures can significantly reduce the risk of both croup and RSV, especially among children and other vulnerable populations.

If a parent or caregiver is unsure about the severity of a child’s symptoms, they should contact a healthcare professional. It is also a good idea to speak with a healthcare professional if an individual is at a higher risk of RSV or croup, such as those with underlying medical conditions, infants born prematurely, and children between 6 months and 3 years old.

People should seek immediate medical care if there is any difficulty breathing, significant discomfort, or a child’s condition worsens. Early and appropriate medical care can prevent complications and ensure proper management of both croup and RSV.

Here are the answers to some commonly asked questions about croup and RSV.

Can you have croup without RSV?

Yes, croup can occur without RSV. Various viruses other than RSV, such as the parainfluenza virus, adenovirus, and influenza viruses, can cause croup.

What does an RSV cough sound like?

An RSV cough can vary, but people often describe it as wheezing or a persistent cough that can sound wet due to mucus in the airways. It may not have the distinctive barking sound typical of croup. Instead, there is a more likely association between RSV coughs and signs of lower respiratory tract infections, such as difficulty breathing or wheezing.

However, these can also be signs of a more serious illness. If a person is experiencing difficulty breathing, they should speak with a healthcare professional.

What can be mistaken for croup?

Conditions that can be mistaken for croup include:

  • asthma
  • bacterial tracheitis, an infection of the trachea
  • epiglottitis, inflammation of the epiglottis, which is the flap at the base of the tongue
  • a foreign body in the airway
  • allergic reactions

Respiratory syncytial virus (RSV) can lead to croup when the infection involves the upper respiratory tract, causing inflammation and narrowing of the airways around the larynx and trachea.

Early recognition of symptoms and timely medical consultation can prevent complications and ensure effective management of both conditions. Both conditions are often treatable at home. However, if an individual’s symptoms worsen or they experience difficulty breathing, they should contact a healthcare professional. Caregivers with infants younger than 6 months who develop symptoms of croup should seek medical treatment.