What is croup

Croup is a viral infection that causes swelling of the windpipe (trachea), the airways to the lungs (the bronchi) and the vocal cords (larynx or voice box). This swelling makes the airway narrower, so it is harder to breathe. Croup causes difficulty breathing, a seal barking cough, and a hoarse voice. The cause is usually a virus, often parainfluenza virus. Other causes include allergies and reflux.

When a child with croup has a cough that forces air through the narrowed airway passages, the swollen vocal cords produce a noise similar to a seal barking. Likewise, taking a breath in often produces a high-pitched whistling sound known as stridor. Stridor generally indicates some obstruction or narrowing of the windpipe. Stridor is also occasionally caused by a condition called epiglottitis. It might also be caused by an inhaled foreign body.

Croup often starts out like a cold. But then the vocal cords and windpipe become swollen, causing the hoarseness and the cough. There may also be a fever and high-pitched noisy sounds when breathing. The symptoms are usually worse at night, and last for about three to five days.

2% of children develop croup annually and it is a common cause of airway obstruction. Children aged from 6 to 36 months are most commonly affected, with most of those children being the ages of 6 months and 3 years have the highest risk of getting croup. They may also have more severe symptoms. Croup is more common in the autumn and winter.

Most cases of viral croup are mild and can be treated at home. You can manage the symptoms in exactly the same way as for a cold. It’s important to try and keep your child calm, because your child can have more trouble breathing if they are upset, frightened or stressed. Croup is most commonly caused by a virus, so antibiotics won’t work. Antibiotics treat only bacterial infections. Steam therapy, including the use of vaporisors, is no longer recommended.

Rarely, croup can become serious and interfere with your child’s breathing. If you are worried about your child’s breathing, see your health care provider right away. Your doctor may prescribe medicines that can help reduce the inflammation and swelling such as oral corticosteroid medicine.

A few children with croup need to go to hospital for observation, to ensure that their windpipes don’t get blocked. While in hospital, your child might initially receive nebulized adrenaline (adrenalin given via a face mask) to relieve the spasm and swelling until the steroids work.

Croup generally resolves after 48 hours of onset of symptoms, however it can last up to a week. In general 5% of children with croup are hospitalized, this rate of hospitalization is increased in children who develop complications of the disease.

Is croup contagious?

Yes, croup is an inflammation of the windpipe (trachea), the airways to the lungs (the bronchi) and the vocal cords (larynx or voice box) that is usually caused by viruses especially parainfluenza virus. However, any virus, bacteria and irritation to the trachea, bronchi and larynx can cause croup.

Can adults get croup?

Yes, but very rarely. For example inflammation of the windpipe (trachea), the airways to the lungs (the bronchi) and the vocal cords (larynx or voice box) can be caused by acid reflux disease or gastroesophageal reflux disease (GERD).

Croup virus

Parainfluenza refers to a group of viruses that lead to upper and lower respiratory infections.

There are four types of parainfluenza virus. They can all cause lower or upper respiratory infections in adults and children. The virus can cause croup, bronchiolitis, bronchitis and certain types of pneumonia.

The exact number of parainfluenza cases is unknown. The number is suspected to be very high. Infections are most common in fall and winter. Parainfluenza infections are most severe in infants and become less severe with age. By school age, most children have been exposed to the parainfluenza virus. Most adults have antibodies against parainfluenza, although they can get repeat infections.

Most infections in adults and older children are mild and recovery takes place without treatment, unless the person is very old or has an abnormal immune system. Medical intervention may be necessary if breathing difficulties develop.

Croup virus symptoms

Parainfluenza virus symptoms vary depending on the type of infection. Cold-like symptoms consisting of a runny nose and mild cough are common. Life-threatening respiratory symptoms can be seen in young infants with bronchiolitis and those with weak immune system.

In general, symptoms may include:

  • Sore throat
  • Fever
  • Runny or stuffy nose
  • Chest pain, shortness of breath, wheezing
  • Cough or croup

Possible Complications

Secondary bacterial infections are the most common complication. Airway obstruction in croup and bronchiolitis can be severe and even life threatening.

Croup virus treatment

There is no specific treatment for the viral infection. Certain treatments are available for the symptoms of croup and bronchiolitis to make breathing easier.

When to see a doctor

Approximately 5 percent of children seen in the emergency department for croup require hospitalization.

You should get medical help immediately if you notice any of the following:

  • Your child makes noisy, high-pitched breathing sounds (stridor) both when inhaling and exhaling
  • Your child begins drooling or has difficulty swallowing
  • Your child seems anxious and agitated or fatigued and listless
  • Your child has difficulty breathing or breathes at a faster rate than usual
  • Your child has noisy breathing when at rest
  • Your child becomes floppy
  • You notice your child’s breastbone being sucked right back
  • Your child becomes restless, distressed, irritable and/or delirious
  • Your child struggles to breathe
  • Your child develops blue or grayish skin around the nose, mouth or fingernails (cyanosis), which usually happens after a coughing spell
  • You’re worried or concerned for any reason

You should call an ambulance (call your local emergency number) immediately if:

  • your child looks very sick and becomes pale and drowsy.
  • your child’s lips are blue in color.

Figure 1. Larynx and pharynx anatomy

anatomy of the pharynx and larynx

Figure 2. Larynx anatomy




Croup complications

Most cases of croup are mild. In a small percentage of cases, the airway swells enough to interfere with breathing.

Croup causes

Croup is usually caused by a virus infection, most often a parainfluenza virus.

Your child may contract a virus by breathing infected respiratory droplets coughed or sneezed into the air. Virus particles in these droplets may also survive on toys and other surfaces. If your child touches a contaminated surface and then touches his or her eyes, nose or mouth, an infection may follow.

Many other conditions can cause croup, some of these other causes include:

  • Supraglottic obstruction (obstruction of the airways occurring above the epiglottis)
  • Acute enlargement of the tonsils
  • Foreign body in the airways
  • Retropharyngeal abscess (abscess behind the tissues of the pharynx)
  • Epiglottitis (rare)
  • Acute angioedema
  • Laryngeal/ subglottic (obstruction occurring below the epiglottis)
  • Viral croup
  • Spasmodic croup
  • Foreign body
  • Bacterial tracheitis (inflammation of the trachea)
  • Laryngomalacia +/- viral infection (in infants)
  • Diptheria
  • Thermal/ chemical injury
  • Intubation trauma
  • Laryngospasm (spasm of the larynx)
  • Tracheal
  • Foreign body
  • Bacterial tracheitis
  • Tumor (e.g. anterior mediastinal lymphoma)
  • Trauma (e.g. hematoma)
  • Congenital abnormality

Risk factors for croup

Most at risk of getting croup are children between 6 months and 3 years of age. The peak incidence of the condition is around 24 months of age.

Risk factors for developing croup include the following:

  • Seasonal variation; with the highest incidence in late autumn, however the condition can occur all year round.
  • Viral infection; 75% of all cases are the result of infection with parainfluenza virus, most commonly type I. Other causes include respiratory syncytial virus (RSV), metapneumovirus, influenza A and B, adenovirus, and mycoplasma.
  • Prematurity
  • Young age
  • Asthma, specifically for spasmodic croup

Croup prevention

To prevent croup, take the same steps you use to prevent colds and flu. Frequent hand-washing is the most important. Also keep your child away from anyone who’s sick, and encourage your child to cough or sneeze into his or her elbow.

To stave off more-serious infections, keep your child’s vaccinations current. The diphtheria and Haemophilus influenza type b vaccines offer protection from some of the rarest — but most dangerous — upper airway infections. There isn’t a vaccine yet that protects against parainfluenza viruses.

There are a few things you can do to try to limit the spread of infection:

  • wash your hands regularly
  • always cough and sneeze into a tissue, before throwing it away immediately
  • clean surfaces regularly to keep them free of germs
  • avoid sharing unwashed cups, plates, cutlery and other kitchen utensils.

Croup symptoms

Croup often begins as a typical cold with a runny nose, sore throat, fever and irritability. If there is enough inflammation and upper airway obstruction and coughing, a child will develop a loud barking cough, sometimes a hoarse voice, and then noisy breathing (inspiratory stridor). The symptoms of croup are worse at night, and is further aggravated by crying and coughing, as well as anxiety and agitation, setting up a cycle of worsening symptoms. Fever and a hoarse voice are common. Your child’s breathing may be noisy or labored.

It is important to note that agitated children can develop life threatening aggravation of symptoms, which is why it is important to keep the child as calm and as happy as possible. As a rule of thumb, older children suffer less severe symptoms than younger children.

These are the symptoms of croup:

  • a barking cough that sounds like a seal
  • a hoarse voice
  • difficulty breathing
  • a rasping sound when breathing in (inspiratory stridor)

Because children have small airways, they are most susceptible to having more marked symptoms with croup, particularly children younger than 3 years old.

In most children, the symptoms improve over three to five days then disappear.

Croup is often only a mild illness, but it can become serious quickly.

Rarely, in severe forms of the disease, features of respiratory distress can occur:

  • Soft tissue recession (indrawing of the skin due to increased effort of breathing)
  • Irritability
  • Lethargy
  • Cyanosis (blue discoloration of the skin due to poor oxygenation of blood)

Because of the increased effort of breathing children may become dehydrated, this may be seen as:

  • Sunken eyes
  • Dry mucous membranes such as dry mouth, dry eyes (i.e. the child will cry with less tears)
  • Reduced urine output
  • Reduced skin turgor i.e. the skin loses its elasticity

Croup diagnosis

Croup is typically diagnosed by the doctor observing your child’s breathing, listening to your child’s chest with a stethoscope and examining your child’s throat. Sometimes X-rays or other tests are used to rule out other possible illnesses.

Things that the doctor is likely to perform when your child is seen may include:

  • Checking the child’s respiratory rate, heart rate and oxygen saturations
  • Looking to see if the child is lethargic, irritable, interacting as they usually would
  • Checking the child for signs of dehydration
  • Doing a complete respiratory examination which includes: looking at the child’s chest to look for evidence of increased effort of breathing, feeling the child’s trachea to see if it has moved, listening to the chest.
  • Other examinations may be performed at the discretion of the doctor depending on the child’s presentation.

Croup treatment

The majority of cases of croup can be treated at home. Still croup can be scary, especially if it lands your child in the doctor’s office, emergency room or hospital. Comforting your child and keeping him or her calm are important, because crying and agitation worsen airway obstruction. Hold your child, sing lullabies or read quiet stories. Offer a favorite blanket or toy. Speak in a soothing voice.

If your child’s symptoms persist beyond three to five days or worsen, your child’s doctor may prescribe a type of steroid (glucocorticoid) to reduce inflammation in the airway. Benefits will usually be felt within six hours. Dexamethasone is usually recommended because of its long-lasting effects (up to 72 hours).  Adrenaline is useful in children with severe croup and respiratory failure. Adrenaline helps to reduce airway inflammation and improve the child’s symptoms immediately. It’s fast-acting, but its effects wear off quickly.

For severe croup, your child may need to spend time in a hospital. In rare instances, a temporary breathing tube may need to be placed in the child’s windpipe.

How to treat croup at home

Croup often runs its course within three to five days. In the meantime, keep your child comfortable with a few simple measures:

  • Stay calm. It is imperative to ensure that the child is comfortable and as unagitated as possible, this can be done by avoiding stressful procedures and examinations. Comfort or distract your child — cuddle, read a book or play a quiet game. Crying makes breathing more difficult.
  • Moisten the air. Although there’s no evidence of benefit from this practice and are not recommended by doctors, many parents believe that humid air helps a child’s breathing. You can use a humidifier or sit with the child in a bathroom filled with steam generated by running hot water from the shower.
  • Hold your child in a comfortable upright position. Hold your child on your lap, or place your child in a favorite chair or infant seat. Sitting upright may make breathing easier.
  • Offer fluids. For babies, water, breast milk or formula is fine. For older children, soup or frozen fruit pops may be soothing.
  • Encourage rest. Sleep can help your child fight the infection.
  • Try a fever reducer. If your child has a fever, over-the-counter medicines, such as acetaminophen (Tylenol, others), may help.
  • Skip the cold medicines. Over-the-counter cold preparations aren’t recommended for children younger than age 2. Plus nonprescription cough medicines won’t help croup.

Your child’s cough may improve during the day, but don’t be surprised if it returns at night. You may want to sleep near your child or even in the same room so that you can take quick action if your child’s symptoms become severe.