What Is Croup? Symptoms & Treatment

If you've ever been startled awake by your child's barking cough in the middle of the night, you may have encountered croup. This common childhood illness can be frightening for parents, especially when hearing that distinctive seal-like cough for the first time. While croup often sounds worse than it actually is, understanding what you're dealing with can help you stay calm and know when to seek medical care.

Croup typically affects young children between 6 months and 3 years of age, though it can occur in older children as well. Most cases are mild and can be managed at home, but it's important to recognize the signs and know how to respond.

Key Takeaways

• Croup is characterized by a distinctive barking cough that sounds like a seal, along with a hoarse voice and sometimes a harsh, high-pitched breathing sound when inhaling (stridor).
• Most cases are mild and can be treated at home with cool mist, staying calm, and keeping your child comfortable and hydrated.
• Croup is contagious and spreads through respiratory droplets, so good hand hygiene is essential to prevent transmission.
• Seek immediate medical attention if your child has difficulty breathing, makes loud breathing sounds at rest, turns blue or pale, or cannot speak or drink due to breathing difficulties.

What Is Croup?

Croup, medically known as laryngotracheobronchitis, is a respiratory condition that causes inflammation and swelling in the upper airways, particularly around the voice box (larynx), windpipe (trachea), and bronchial tubes. This swelling narrows the airway, making it harder for air to pass through and creating the characteristic sounds associated with croup.

The condition primarily affects young children because their airways are naturally smaller and more prone to significant narrowing when inflammation occurs. While croup can happen at any time of year, it's most common in the fall and early winter months.

What Causes Croup?

Croup is most commonly caused by viral infections. These include:

• Parainfluenza virus
• Respiratory syncytial virus (RSV)
• Influenza
• COVID-19
• Adenovirus
• Common cold viruses.

These respiratory infections cause the lining of the windpipe and voice box to become inflamed and swollen. In young children, even a small amount of swelling can significantly narrow the airway, which explains why croup is more common and more severe in toddlers and young children than in older kids or adults.

In rare cases, croup can be caused by bacterial infections, allergies, or inhaled irritants, but viral croup is by far the most common form parents will encounter.

Is Croup Contagious?

Yes, the viruses that cause croup are contagious, however, another child who catches the same virus may not develop croup. Since it's typically caused by viruses, croup can spread from person to person through respiratory droplets when an infected person coughs, sneezes, or talks. The virus can also spread by touching contaminated surfaces and then touching the face, nose, or mouth.

Children with croup are most contagious during the first few days of illness or while they have a fever. The incubation period—the time between exposure to the virus and the start of symptoms—is typically 2 to 6 days. Adults can get the same viruses that cause croup; however, they rarely develop croup symptoms because the diameter of their upper airway is larger than in children.

To reduce the spread of croup, encourage frequent handwashing, avoid sharing cups or utensils, and keep your child home from daycare or school until they're feeling better and fever-free for at least 24 hours. Clean and disinfect frequently touched surfaces regularly.

What Are The Symptoms?

Croup typically begins like a common cold, with a runny nose, congestion and mild fever. After a day or two, the distinctive bark and other croup symptoms develop.

“Croup can sound really scary—that barking cough can make any parent’s heart race,” said Katherine Stalbaum, MD, a St. John, Ind., pediatrician with Franciscan Physician Network.  “But here’s some reassurance: croup almost always sounds worse than it really is. If your little one can talk, cry, and drink between those coughing spells, that’s a really positive sign. The sound is scary, but most kids with croup are not in real distress.”

Symptoms of croup

• A harsh, barking cough that sounds like a seal or a dog barking is one of the most common croup symptoms. This cough is often worse at night and may come in sudden episodes.
• Stridor is a harsh, high-pitched breathing sound that occurs when your child breathes in. It happens because air is being forced through a narrowed airway. Stridor may only be noticeable when your child is crying, coughing, or active, but in more severe cases, it can occur even at rest.
• Hoarse voice develops because of inflammation around the vocal cords. Your child may sound raspy when they talk or cry.
• Labored breathing may occur as your child works harder to breathe. You might notice their chest or the area between their ribs pulling in with each breath (retractions).

Symptoms are often worse at night and typically last 3 to 5 days. The barking cough may persist for up to a week. Many children improve during the day but experience worsening symptoms when they settle down for sleep.

How Is Croup Different From RSV?

Both croup and respiratory syncytial virus (RSV) are common viral respiratory illnesses in young children, and they can sometimes be confused because they both affect breathing. However, there are key differences:

• Location of inflammation: Croup affects the upper airways (larynx and trachea), causing the characteristic barking cough and stridor. RSV primarily affects the lower airways (bronchioles), leading to wheezing and rapid breathing.
• Distinctive sounds: Croup produces a barking cough and stridor (a harsh sound when breathing in). RSV typically causes wheezing (a whistling sound when breathing out) and a wet, congested cough.
• Age groups most affected: While both can affect young children, RSV is most dangerous for infants under 6 months, while croup most commonly affects children between 6 months and 3 years.
• Symptom progression: Croup symptoms often worsen at night and may improve during the day. RSV symptoms tend to be more consistent throughout the day and night and progressively worsen over several days before improving.

It's worth noting that RSV itself can sometimes cause croup, and children can have both RSV and croup at the same time. If you're unsure what your child has, or if symptoms are concerning, contact your pediatrician.

How Is Croup Treated?

Most cases of croup are mild and can be managed at home with supportive care. The goal is to keep your child comfortable while the virus runs its course.

“When your child has croup, one of the best things you can do is try to stay calm—even though I know that’s not always easy,” said Dr. Stalbaum. “Kids pick up on our anxiety, and when they get upset or start crying, it can actually make their breathing sound worse. So take a deep breath, hold your child upright, and speak in a soothing voice. Your calmness is part of their healing.”

Home treatments include:

Cool mist therapy: Taking your child into a steamy bathroom or exposing them to cool night air can help ease breathing. Some parents find that running a hot shower to create steam in the bathroom provides relief. Others take their child outside briefly to breathe cool air.

Keeping your child calm: Crying and agitation can make breathing more difficult, so comfort your child and keep them as calm as possible. Hold them in an upright position, which can make breathing easier.

Hydration: Offer plenty of fluids to prevent dehydration. Breast milk, formula, water, or diluted juice are all good options.

Fever management: If your child has a fever and seems uncomfortable, acetaminophen or ibuprofen (for children over 6 months) can help.

Medical treatments for moderate to severe croup:

If symptoms are more severe or your child is struggling to breathe, seek medical care.

"We have excellent treatments for croup,” Dr. Stalbaum said. “Parents are sometimes hesitant about steroids, but for croup, they're safe, effective, and can prevent the condition from becoming an emergency."

To treat your child’s croup symptoms, your doctor may prescribe:

Corticosteroids (like dexamethasone or prednisolone): These medications reduce inflammation in the airways and are highly effective at treating croup. A single dose often significantly improves symptoms within hours.

Nebulized epinephrine: For severe cases with significant breathing difficulty, nebulized epinephrine can provide rapid relief by reducing airway swelling. This is typically administered in a medical setting.

Most patients with croup recover fully without long-term consequences.

When Should I See a Doctor For Croup?

While most croup is mild, certain symptoms require urgent medical care.

Go to the emergency room or call 911 if your child

• Has stridor (harsh breathing sounds) at rest
• Shows severe difficulty breathing, including rapid breathing, deep retractions, or gasping
• Has bluish or grayish skin, especially around the lips or fingernails
• Cannot speak, cry, or make sounds due to breathing difficulty
• Drools or has extreme difficulty swallowing
• Appears exhausted, very ill, or unusually drowsy
• Cannot drink fluids

Contact your pediatrician during regular hours if

• This is your child's first episode of croup
• Symptoms aren't improving after a few days
• Your child isn't drinking enough fluids
• You're concerned about your child's condition

Croup can be scary when you first experience it, but remember that it's a common childhood illness and most children recover completely within a week. Trust your parental instincts—if something doesn't feel right or your child seems to be getting worse, don't hesitate to seek medical advice.

“I always tell parents: you know your child best. If something feels off—if they seem more tired than usual, they’re not acting like themselves, or if your gut is telling you something is wrong—call us,” Dr. Stalbaum said. “I’d much rather have you bring your child in and work through your concerns together than have you wait at home feeling worried and unsure. That’s what we’re here for.”

With proper care and attention, your little one will be back to their normal self soon.