Croup: Symptoms, Treatments, & When to Worry

By Howard Jeffries, MD
Medically reviewed checkmarkMedically reviewed
April 23, 2020

Known for its trademark barking cough, croup occurs when a person’s upper airways swell and is typically caused by a virus, although it can also be caused by allergies or stomach reflux. Croup is most commonly associated with a loud, barking cough that sounds like a seal, croup can also cause other symptoms.

Since croup is most frequently caused by a viral infection, it can also be accompanied by a fever, fatigue, and general malaise. Some cases of croup also lead to difficulty breathing or breathing with a whistling sound, which is known as stridor. In situations in which one develops difficulty breathing from croup, it’s always important to seek immediate medical care.

In most cases, croup resolves on its own within five days, and is generally not serious. However, some people experience more persistent or recurrent cases of croup. While croup is more common in babies and young children, adults can also experience croup and its potential complications.

What Is Croup?

Croup is an upper airway infection that can obstruct breathing and cause a barking cough, similar to the sound of a seal barking. This infection can cause swelling around the larynx (voice box), trachea (windpipe), and bronchi (bronchial tubes). The well-known barking sound occurs due to vocal cord swelling, which can also cause a whistling sound during breathing.

Croup can be scary for parents and children, but generally, it isn’t serious. It’s more common in younger children around 3-5 months of age, but it can occur in older children and adults, too. Usually, it’s worse at night, and it resolves on its own within five days.

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Viral croup

Viral croup is caused by a viral infection of the voice box and windpipe and is the most common type of croup. It’s usually characterized by a cold that progresses into a barking cough. Generally, viral croup comes with a low fever, but some children’s fevers can climb as high as 104° F (40° C). Keep in mind that this type of croup is contagious, since it is caused by an infection. Children who have viral croup are likely contagious for three days after the illness begins, or until the fever is gone.

Spasmodic croup

Not all cases of croup are caused by infections. Spasmodic croup, for example, is caused by allergies or reflux from the stomach. It can be similar to asthma, leading to a barky cough and difficulty breathing, typically in the middle of the night. Since there’s no infection associated with spasmodic croup, there’s not usually a fever, either.

Croup with stridor

Stridor, which is a whistling sound that occurs when someone takes a breath, can occur in mild cases of croup, often when a child is breathless due to crying or activity. However, the croup may be more severe if a child’s breathing sounds like whistling when they’re resting. In some cases, croup with stridor can cause low oxygen in the blood, which requires immediate medical care.

Croup Symptoms

The trademark barking cough is the most common symptom of croup, but it can cause other symptoms, including:

  • A loud cough that gets worse with crying, agitation, or activity
  • Fever
  • Hoarse voice
  • Noisy or labored breathing

Croup in adults

While croup is vastly more common in younger children, adults can experience it, too. The most common signs of croup in adults include:

  • A barking cough that worsens at night
  • Noisy or labored breathing
  • Fever
  • General malaise
  • Fatigue

Causes of Croup

Croup is most commonly caused by a viral infection of the windpipe. It starts out with cold-like symptoms, with the cough progressively changing to the hallmark barking cough. However, croup can also be caused by:

  • Allergies
  • Reflux
  • Bacterial infections
  • Fungal infections

Croup Diagnosis

To diagnose croup, medical providers listen for the trademark barking and whistling sounds that can occur with coughing and breathing. The doctor will also probably ask about your child’s other symptoms, including fever, runny nose, and congestion, and if your child has a history of upper respiratory problems, including croup.

Usually, a physical exam is sufficient for a croup diagnosis. In some cases, a doctor might order a neck x-ray if a severe case of croup isn’t improving even after treatment.

Croup Treatment

As with any other illness, how your doctor treats you or your child’s croup depends on the suspected cause and severity.

Treatment for mild croup

Most cases of mild croup resolve on their own within 3-5 days. Since most cases of croup are viral, your doctor will likely encourage you to treat symptoms.

For example, you can lower a child’s fever with fever-reducers like acetaminophen or ibuprofen (if your child is older than six months). Make sure to talk to your child’s medical provider to determine the best course of action.

Cold medicine won’t help with croup. In general, over-the-counter (OTC) preparations aren’t recommended for children, and they can be harmful for children younger than age two.

Treatment for severe croup

It’s uncommon for croup to linger for longer than a few days. In more severe cases of croup and for those that last more than five days, a doctor may recommend medications to control croup symptoms, such as:

  • Steroids, like dexamethasone, to reduce inflammation of the airways
  • Epinephrine in the form of an inhaled nebulizer to reduce airway inflammation

Treatment for spasmodic croup

If your child has spasmodic croup due to allergies or asthma, the doctor may recommend OTC or prescription medicine to help with breathing.

At-home remedies for croup

Since cough and difficulty breathing can get worse when a child is upset, comforting a crying child can help reduce symptoms. Other at-home remedies for croup include:

  • Humidifiers: Run a cool-mist humidifier in your child’s room or sit in the bathroom for 10-15 minutes with a hot shower running, as steam may calm severe coughing episodes.
  • Time outside: Take your child outside for a few minutes in cooler weather.
  • Elevated sleeping: Prop your child’s mattress up, as being upright could make it easier to breathe.
  • Rest: Encourage your child to drink plenty of fluids and rest.

Prevention of Croup

To prevent croup, focus on preventing viral illnesses like colds and influenza. The following measures can lower your child’s chances of developing croup:

  • Frequent hand washing
  • Avoiding contact with sick people
  • Avoiding sharing drinks or food with someone who’s sick

Risk Factors and Complications

Most cases of croup are mild and resolve on their own. But croup can also become serious and cause your child to struggle with breathing, which can lead to lack of oxygen in the blood. If your child is experiencing difficulty breathing or is developing blue lips or fingernails, seek medical care in the emergency department or call 911 immediately.

Rarely, recurring or persistent croup can be the result of an airway issue that’s not related to an infection, which could be a congenital problem. In this case, your child’s doctor may refer you to an ear, nose, and throat doctor (otolaryngologist) or a lung specialist (pulmonologist).

When to See a Doctor

Always reach out to your child’s medical provider if your child’s croup isn’t improving after a few days. Some cases warrant immediate care. Go to the emergency department or call 911 if you or your child:

  • Makes a whistling sound while breathing that continuously gets louder
  • Can’t make noises or speak due to lack of breath
  • Appears to be struggling with breathing
  • Develops bluish lips or fingernails
  • Becomes very tired or difficult to awaken
  • Becomes dehydrated (no tears while crying, peeing less, or sunken eyes)
  • Develops stridor (whistling sounds while taking a breath) while at rest
  • Finds it difficult to swallow saliva or starts drooling

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K Health articles are all written and reviewed by MDs, PhDs, NPs, or PharmDs and are for informational purposes only. This information does not constitute and should not be relied on for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.

Howard Jeffries, MD

A pediatric cardiac intensivist at Seattle Children's Hospital, Dr. Jeffries is also Senior Medical Director, Regional Network. He completed a residency in pediatrics and a fellowship in pediatric intensive care. He has published chapters and peer-reviewed articles, with an emphasis on cardiac intensive care, informatics, outcomes assessment and quality improvement.