Alternative name: Laryngo-tracheo bronchitis or LTB
Croup is an acute, viral inflammation of the upper and lower respiratory tract. It mainly involves the:
- Larynx – the “voice box” containing the vocal chords
- Trachea – the windpipe
- Bronchi – the large airways leading to the lungs
- Bronchioles – the small airways in the lungs
- Lung tissue
The main symptoms are caused by swelling and inflammatory secretions in the larynx, the area immediately around the vocal chords. This obstruction results in difficult breathing, especially during inhalation (when breathing air in).
Croup most often occurs in children, and the laboured breathing usually tires the child very much.
In very severe cases, the lungs are unable to work efficiently in moving oxygen into the blood, with the result that the child may become depleted of oxygen.
Croup is characterised by inspiratory stridor (a harsh, crowing sound when inhaling air), subglottic swelling (swelling below the vocal chords), and respiratory distress that’s most pronounced during inspiration.
Acute epiglottitis is a condition that should always be considered when children present with croup. Here a bacterial infection caused by bacteria known as Haemophilus influenzae results in acute swelling of the epiglottis, the small flap of tissue at the back of the throat that guards the airway entrance to the lungs. This can rapidly lead to upper airway obstruction. If the diagnosis isn’t made promptly, the child is at serious risk of dying.
In many developed countries, according to the World Health Organization (WHO), croup is caused by parainfluenza or influenza virus. Bacterial infection is rarely the cause.
Who gets croup?
Viral croup occurs mainly in children between three months and five years of age, affecting boys more often than girls. Croup affects approximately 15-20% of children during the early years of life.
Although the incidence of croup is uncommon after the age of five years, it’s sometimes diagnosed in preteens and adolescents. It rarely occurs in adults, a result of the larger breathing passages that can accommodate inflammation without getting obstructed.
Seasonal outbreaks of croup are common. In winter, when it’s colder, croup occurs more often, but it can occur at any time of year.
Some children appear to be more prone to croup than others.
Symptoms of croup
Croup is usually preceded by two or three days of an upper respiratory tract infection (like a cold or flu).
Characteristically, a barking, often spasmodic cough and hoarseness develop as the inspiratory croup starts. Gagging and vomiting may occur with the typical barking cough.
Fever is common during an episode of croup. A high fever of 38-40°C is associated with the onset of croup. This usually occurs in the middle of the night. The child wakes up with breathing difficulty and rapid breathing, using all chest muscles. As symptoms become more severe and the child tires, he or she may become blue (cyanosed) due to the lack of oxygen.
Seek immediate medical attention if your child struggles to breathe, makes noisy, high-pitched breathing sounds when breathing air in, has difficulty swallowing, and especially if your child’s skin is blue or has a grey colour around the nose, mouth or fingernails.
What causes croup?
Croup is mostly caused by viruses. Most commonly the parainfluenza viruses (a group of four viruses) are involved, but the respiratory syncytial virus (RSV), influenza A and B, as well as the adeno, rhino and measles viruses can also cause croup.
The common bacterial causes are Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis and Mycoplasma pneumonia.
Croup associated with influenza can be particularly severe, and may occur outside the usual croup age group of three months to five years. In winter and spring, RSV and influenza viruses tend to dominate, but in autumn the parainfluenza virus is found more often.
The disease can be spread by infected droplets and close contact with infected individuals. Infection can occur through the eyes, nose and mouth.
Risk factors for croup
The main risk factors for croup are as follows:
- Being between the ages of three months and five years
- Exposure to other children with croup (in crèches)
- Male gender
There may be an increased risk for croup in young children with certain food allergies such as cow’s milk and egg allergy.
Course and prognosis of croup
Most croup patients can be cared for at home, but caregivers need to be alert to deterioration of the condition. If acute symptoms develop, the child should be treated at an emergency department. In most cases, medication will settle the inflammation in a few hours and the child’s immune system will fight the virus infection.
The illness usually lasts about three days, but a cough can continue for another two weeks.
Croup can sometimes recur after a short period or even every year, but as the child grows and the diameter of the airways increases, the inflammation affects the airways less and less. Thus, children eventually outgrow the tendency to get croup.
How is croup diagnosed?
The history of the patient usually provides valuable information that can make a diagnosis of croup quite obvious.
In early stages, or if the person isn’t severely affected, there may just be a typical barking cough that may signal croup.
In more severe cases, there’ll be obvious breathing problems and often a harsh stridor (a high-pitched or squeaking noise while breathing air into the lungs).
Listening to the chest with a stethoscope will reveal long inspiration times and stridor over the larynx. About 50% of children with croup have a fever.
Acute epiglottitis (swelling of the small flap of tissue in the back of the throat that guards the airway entrance to the lungs) needs to be excluded if the condition seems severe. An X-ray of the soft tissues of the neck may show a markedly swollen epiglottis.
The possibility of an inhaled foreign body must always be ruled out.
How is croup treated?
Admission to hospital is likely to be necessary if there are breathing difficulties and stridor is present, both on inspiration as well as expiration. If a child becomes ill in the evening, it’s likely to worsen later on, so admission is generally a good idea.
Croup can be frightening for children, parents and healthcare workers. Children need to be comforted and reassured. Often the symptoms settle down as soon as the child stops struggling (but this may prove difficult). Close monitoring is important during the early stages of croup, as breathing difficulties can develop rapidly.
Minimal handling helps to settle children down. They should be nursed in a warm, humid environment, and not be sedated with medication. Taking fluids should be encouraged, but forcing fluids shouldn’t be necessary. Activity should be kept to a minimum in the first few days.
Croup is infectious during the first few days and others in the household may be infected. However, infection usually only causes a sore throat or cough in older children and adults. When the temperature has settled and the child has recovered, he or she can go back to a day-care centre.
In the case of epiglottitis, the airway can become blocked within six hours from onset of the disease. The ill child shouldn’t lie down (as this may obstruct the airway) and must be taken to an emergency department immediately. Here the airway may need to be secured by intubation. But since this may fail, invariably leading to complete obstruction, it’s usually necessary to create a surgical airway (known as a tracheostomy).
Antibiotics should be administered intravenously and the child should be admitted to a paediatric intensive care unit under the care of a paediatrician.
If the breathing symptoms are mild and the child isn’t distressed, croup can be managed at home.
However, children must be observed carefully overnight, as symptoms may worsen in the middle of the night when there’s no one around. When children with croup wake up during the night with difficulty breathing and clearing the airways, it’s important to calm them to prevent a vicious cycle of cough and further irritation.
Children can be distracted by reading with them or rocking them. Keep them quiet if possible.
Moisture in the air can make it easier for the ill child to breathe. Use a cool humidifier or vaporiser. Although steam hasn’t been proven to lessen symptoms, it soothes the airways. Whenever it makes the child more distressed, however, it should be stopped immediately. Distress worsens the condition more than the treatment helps. Always be careful not to scald your child. A bath may help by creating sufficient humidity in the bathroom.
In young babies, blocked noses can make breathing more difficult. The child’s nose can be cleaned gently with careful instillation of salt-water nose drops (1/4 teaspoon of table salt in one cup of water) into the nasal openings every few hours.
This should be followed by gentle suction using an ear bulb syringe. Initially, paracetamol or ibuprofen syrup may help, especially to control fever. Aspirin shouldn’t be given in children with viral illnesses, as it may cause Reye’s syndrome, a rare but serious illness that can affect the liver and brain.
If the child’s health still doesn’t improve, taking him or her into cool night air may help. Children often improve in the car on the way to the hospital. If the symptoms improve, sleeping with the child for the rest of the night is important. If there are any doubts, see a doctor – sometimes too long a delay may be fatal.
Antibiotics have no place in the management of croup, unless it’s used for the treatment of epiglottitis (swelling of the small flap of tissue in the back of the throat as a result of bacterial infection).
The initial treatment is the inhalation of nebulised adrenaline through a face mask.
This may be required frequently as the effect of the adrenaline wears off within half an hour. A cortisone solution known as Pulmicort (budesonide), which is given through a nebuliser, is very effective in treating croup in young children.
A single injection of the corticosteroid dexamethasone is sometimes considered in severe croup. The stress leading up to the injection is usually considerably less than trying inhalation masks. However, if the child tolerates inhalation without distress, this may be useful.
Oral corticosteroid syrup or tablets (prednisone) may be beneficial for the next few days to settle the inflammation, and should be taken as soon as possible, as the onset of action is delayed by several hours.
Antibiotics are essential for epiglottitis. Ceftriaxone is usually advised and must be given intravenously.
Surgery is only of relevance in epiglottitis when an artificial airway (tracheostomy) needs to be created following a failed intubation. This is an emergency procedure and is followed by insertion of a tracheostomy tube, which is then connected to a mechanical ventilator.
Croup: When to call the doctor
A doctor should be consulted promptly when a child develops any signs of croup, especially when a barking cough sets in and stridor (a rough, raspy, high-pitched sound) develops when the child inhales.
It’s an emergency requiring immediate medical attention if:
- Breathing difficulties are severe
- The skin, fingernails or lips turn blue or grey
- Abnormally fast, shallow breathing develops (more than 50 breaths a minute)
- The child can’t seem to get enough air
- The croup symptoms don’t improve after 20 minutes of inhaling either steamy bathroom air or cool outdoor air
- The child has stridor on both expiration as well as inspiration
Some bacterial infections (epiglottitis) can have similar symptoms to those of croup. The stridor is soft, with snoring or gurgling exhalations. Cough isn’t very prominent. In very rare cases, when the airways become totally blocked, such infections can be rapidly fatal.
The child should be taken to an emergency department immediately if he or she:
- Has a high fever
- Appears very sick
- Drools saliva and is unable to swallow
- Needs to lean forward with the mouth open in order to breathe
- Is struggling to breathe
The doctor should be made aware of all medication used over the previous few days. It’s important to know the names and doses.
How can croup be prevented?
It’s not always possible to avoid the viruses and infections that lead to croup, but these steps might help:
- Avoid close contact with adults and young children who have cold and/or flu symptoms
- Wash your and your child’s hands frequently
- Don’t allow your child to share toys and utensils with other children when they are ill
- Breastfeed your baby: not only does it help with building a strong immune system, it also helps to relax the child and ease breathing
Reviewed by paediatrician Prof Eugene Weinberg. MBChB; FCP (SA); PAED (SA). March 2018.