Croup usually causes symptoms for around 2 days. However, it may last for up to 2 weeks. Symptoms such as a barking cough can peak within 1–3 days, but a mild cough may persist for longer

Croup is an illness in the respiratory tract that most commonly occurs due to human parainfluenza viruses (HPIVs).

Most cases of croup are mild, but it can be severe in some cases.

Read on to learn more about how long croup can last. This article also looks at how croup develops, how long it is contagious, and more.

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Most children have croup symptoms for around 48 hours.

However, in some cases, croup may last for up to 2 weeks.

Croup is extremely rare in adults.

A 2017 case study reported that English-language medical literature had described only 15 cases. There is not enough data to work out how long croup generally lasts in adults.

However, in the case study, a 25-year-old woman had croup symptoms for 3 days before reporting for treatment, and then for 3 days after, totaling 6 days of symptoms.

According to the United Kingdom’s National Health Service (NHS), croup symptoms usually peak after 1–3 days. After this time, symptoms usually begin to improve.

A mild cough may continue for around another week.

Symptoms of croup develop due to upper airway swelling. They may include:

  • a cough that sounds like a bark
  • hoarseness while speaking
  • breathing difficulties
  • stridor, which is a squeaking or whistling sound

Stridor is most obvious when crying or coughing. In cases of severe croup, it can occur while sleeping or resting. If this is the case, it is important to seek immediate medical help, as this can indicate severe respiratory distress.

Some children appear to have a cold for a few days before showing typical croup symptoms. They may have the following:

Croup symptoms are more likely to occur during late fall or early winter, although they can develop at any time of year.

There are several types of croup, which may affect the symptoms that develop.

Viral croup is the most common type and often starts with cold-like symptoms before progressing to croup symptoms.

Spasmodic croup may develop as a response to an allergy or stomach acid moving back up the digestive tract. It can come on suddenly in the middle of the night.

Symptoms of spasmodic croup can include a barking cough and stridor, but it typically does not cause fever.

According to the Centers for Disease Control and Prevention (CDC), HPIV — the most common cause of croup — is usually most contagious during the early stages of the illness. It can spread when a person with HPIV coughs, sneezes, or breathes.

HPIVs can spread to others through droplets that stay in the air for over an hour. They may stay on surfaces for several hours.

When symptoms resolve, contagiousness typically resolves too. This is because a person will no longer be coughing or sneezing.

Croup symptoms are typically worse at night. A child may go to sleep without symptoms but experience stridor and a barking cough during the night.

A review from 2008 put forward several possible explanations for this, although no evidence confirms a single underlying cause of croup’s night-time symptoms. Reasons may include:

  • sleep-cycle-related changes in levels of the stress-linked hormone cortisol
  • increased inflammation in tissues at night
  • stomach acid moving back up the digestive tract

Learn about the causes of nighttime coughing in toddlers.

Treatments for croup do not necessarily shorten how long it lasts, but they can help with managing or reducing the severity of symptoms.

Treatment may involve:

  • providing comfort during periods of distress, as crying can worsen symptoms
  • keeping a child upright and limiting how much they can lie down
  • making sure they drink enough fluids to maintain hydration
  • giving them liquid acetaminophen or ibuprofen to improve comfort and reduce fever, if a doctor or pharmacist recommends it
  • checking in on a child with croup at night regularly

Children with severe croup may require hospital admission. There, a physician may prescribe epinephrine and a single dose of steroid medications to reduce swelling.

A child who is experiencing breathing problems may receive supplemental oxygen or intubation to help them breathe easier while the windpipe has swollen.

It is important to seek medical advice if a child experiences breathing problems.

Learn more about remedies for croup.

It is not clear from current research how long a child may have croup after taking steroid medications.

However, a 2018 meta-review of 43 randomized, controlled trials involving 4,565 children found that treatment with a type of steroid known as glucocorticoids improved symptoms within 2 hours and reduced the overall length of hospital stay by around 15 hours.

The findings of this review suggest that steroids can shorten the timeframe of severe croup symptoms.

Croup usually causes symptoms for 2 days, followed by a period of reduced symptoms that may last for up to 2 weeks. Symptoms can include a barking cough, stridor, and breathing problems. They usually get worse at night.

Doctors often ask parents to support recovery through soothing, fluids, pain relief medications, and keeping a child upright as much as possible.

Medical interventions for severe croup include steroid medications, which may reduce a child’s time in the hospital. A doctor may also give epinephrine to reduce swelling.