At a glance

  • Croup occurs if the larynx (voice box) becomes inflamed.

  • It is most common in toddlers.

  • The inflammation is caused by a virus.

  • The typical symptoms include a barking cough, raspy sounds when breathing in (stridor), and slight breathing difficulties.

  • If the breathing difficulties are severe, steroid medication can help.


Photo of a father and his son (PantherMedia / Monkeybusiness Images) The germs that cause common colds can spread in the airways and lead to inflammations. If young children have a cold and the area around their larynx (voice box) becomes inflamed too, it's known as croup.

The typical symptoms include a barking cough, raspy sounds when breathing in (stridor), and slight breathing difficulties. The symptoms usually go away on their own. If they last longer, though, or if the breathing difficulties get worse, medication such as steroids can help.

The medical term for croup is “laryngotracheobronchitis.” This means inflammation of the larynx (voice box), trachea (windpipe) and bronchi (airways to the lungs).


Typical croup symptoms include the following:

  • a “barking” cough
  • raspy sounds when breathing in (stridor)
  • a hoarse voice

Because the swelling makes the larynx narrower, children who have croup breathe faster and take deeper breaths. Although they usually only have slight difficulties breathing, they often feel scared and cry. This can make the breathing difficulties worse.


Croup usually develops as part of an infection with viruses that cause a common cold. In most cases, certain types of viruses known as parainfluenza viruses are to blame. Although they often only lead to typical common cold symptoms, they sometimes also cause the mucous membranes in the area around the larynx (voice box) to become inflamed and swollen.


Croup often occurs in the colder months of the year. It is most common in children between the ages of six months and three years: About 3 out of 100 children in this age group have croup per year. Adults only rarely have it.


Children often have a cold with a runny nose and slight fever at first. After a few days, the typical croup symptoms might start – in most cases, suddenly at night.

Most children only have slight breathing difficulties that go away on their own within two days.


It is rare for croup to cause very severe breathing difficulties in children. If that does happen, though, it's important to call the emergency services (112 in Germany and many other countries, 911 in the U.S.) and ask for an ambulance. One typical warning sign is the skin between their ribs being visibly drawn in with each breath. In rare cases the child may turn blue. The strained breathing may be so exhausting that the child appears to be distant and mentally absent.

These severe symptoms may occur if the windpipe is inflamed as well, and is too narrow as a result (a condition known as stenosing laryngotracheitis). Or they could be caused by a pus-producing inflammation of the epiglottis (a flap in the throat that prevents food and fluids from entering the windpipe and lungs when you swallow).


Croup can often be diagnosed without doing any special tests or examinations: If a child develops the typical symptoms during a cold or shortly afterwards, it is quite likely to be croup.

But if they have serious breathing difficulties it's important to have a doctor take a closer look. The doctor will examine their throat and larynx (voice box). A procedure known as a laryngoscopy may need to be done for this. If it is thought that the inflammation might be caused by bacteria, a throat swab might be taken.


The symptoms usually stay mild, and medication generally isn't needed. People are often advised to open the windows: Fresh, cool and moist air is thought to relieve the symptoms. But this hasn’t been proven in scientific studies.

It's important to stay as calm as possible, be there for the child and reassure them so that their breathing difficulties aren't made worse by fear.

If the symptoms don’t improve or are a real problem for the child, they need to see a doctor. Serious breathing difficulties might have to be treated in a hospital. The child will usually be given steroids – for instance, in the form of a suppository or tablet, or sometimes as an injection or spray.

These medications reduce the inflammation and swelling. Several studies have found the following: Children who were given steroid medication got better sooner than children who were given a fake medication (placebo) did. Those who received steroids were also less likely to need further treatment from a doctor.

The short-term and sometimes single use of steroid medications hardly causes any side effects. But these medications only start working after about two hours. If more urgent treatment is needed for severe breathing difficulties, adrenaline (epinephrine) is used instead. The child inhales it in the form of a fine mist using a device known as a nebulizer. Adrenaline makes the blood vessels in the membranes lining the airways narrower, which typically reduces the swelling within half an hour. The possible side effects include a racing heart and an increase in blood pressure. As well as being given medication, children who have serious breathing difficulties are usually given oxygen through an oxygen mask too.

Further information

When people are ill or need medical advice, they usually go to see their family doctor or pediatrician first. Read about how to find the right doctor, how to prepare for the appointment and what to remember.