At a glance

  • Croup is an inflammation of the area around the larynx (voice box).
  • It is most common in children.
  • It is caused by a viral infection.
  • The typical symptoms include a barking cough, raspy sounds when breathing in (stridor), and slight breathing difficulties.
  • Steroids are effective in relieving serious breathing problems.


Photo of a father and his son

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 of the larynx (voice box), trachea (windpipe) and (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 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 inward 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 (stenosing laryngotracheitis). Or they could be caused by a pus-producing 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 might be caused by , 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.


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 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.

Aregbesola A, Tam CM, Kothari A et al. Glucocorticoids for croup in children. Cochrane Database Syst Rev 2023; (1): CD001955.

Bjornson C, Russell K, Vandermeer B et al. Nebulized epinephrine for croup in children. Cochrane Database Syst Rev 2013; (10): CD006619.

Johnson DW. Croup. BMJ Clin Evid 2014: 0321.

Lenarz T, Boenninghaus HG. Hals-Nasen-Ohren-Heilkunde. Berlin: Springer; 2012.

Moraa I, Sturman N, McGuire TM et al. Heliox for croup in children. Cochrane Database Syst Rev 2021; (8): CD006822.

Pschyrembel online. 2023.

IQWiG health information is written with the aim of helping people understand the advantages and disadvantages of the main treatment options and health care services.

Because IQWiG is a German institute, some of the information provided here is specific to the German health care system. The suitability of any of the described options in an individual case can be determined by talking to a doctor. can provide support for talks with doctors and other medical professionals, but cannot replace them. We do not offer individual consultations.

Our information is based on the results of good-quality studies. It is written by a team of health care professionals, scientists and editors, and reviewed by external experts. You can find a detailed description of how our health information is produced and updated in our methods.

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Updated on March 16, 2023
Next planned update: 2026


Institute for Quality and Efficiency in Health Care (IQWiG, Germany)

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