What Is Croup? Symptoms, Treatment & When to Seek Emergency Care for Your Child

What Is Croup and What Causes It?

Croup (acute laryngotracheobronchitis) is a viral respiratory infection that causes inflammation and swelling of the voice box (larynx), windpipe (trachea), and bronchial tubes. This swelling narrows the airway, producing the characteristic barking cough and stridor that make croup instantly recognizable.

Croup is one of the most common respiratory illnesses in young children, accounting for approximately 15% of pediatric respiratory tract infections seen in clinical settings. The condition primarily affects children between the ages of 6 months and 3 years, with peak incidence occurring around 2 years of age. By age 5-6, most children have outgrown their susceptibility to croup, as their airways have grown larger and can better tolerate the swelling caused by viral infections.

Understanding the Viral Causes of Croup

Croup is caused by several common respiratory viruses, with parainfluenza viruses being responsible for approximately 75% of all cases. The parainfluenza viruses (types 1, 2, and 3) are the predominant cause, particularly type 1, which tends to cause epidemics in the fall of odd-numbered years in temperate climates.

Other viruses that can cause croup include:

• Respiratory Syncytial Virus (RSV): A common cause of respiratory infections in infants and young children, RSV can also trigger croup symptoms, particularly in children under 1 year
• Influenza viruses: Both influenza A and B can cause croup, often with more severe symptoms than parainfluenza-associated croup
• Adenoviruses: These viruses can cause a variety of respiratory infections, including croup
• Rhinoviruses and enteroviruses: Common cold viruses that occasionally lead to croup in susceptible children
• Human metapneumovirus: A relatively recently identified virus that can cause croup-like symptoms

Why Do Young Children Get Croup?

The reason croup predominantly affects young children relates to the anatomy of their airways. In infants and toddlers, the subglottic region (the area just below the vocal cords) is the narrowest part of the airway. In adults, the narrowest point is at the vocal cords themselves. The pediatric airway is not only narrower but also more compliant, meaning it's more susceptible to collapse when swelling occurs.

When a viral infection causes inflammation in this area, even a small amount of swelling can significantly reduce the airway diameter. The resistance to airflow increases exponentially as the airway narrows—halving the airway radius increases resistance to airflow by 16 times. This explains why the same virus that might cause a simple cold in an older child or adult can cause significant breathing difficulties in a toddler.

Seasonal Patterns of Croup

Croup follows distinct seasonal patterns, with most cases occurring in the fall and early winter months. This timing coincides with the peak circulation of parainfluenza viruses. In temperate climates, you can expect to see increased croup cases from September through December, with a smaller peak sometimes occurring in spring.

The seasonal nature of croup means that parents of young children should be particularly vigilant during these months, especially if their child has had croup before or is prone to respiratory symptoms with viral infections.

Different Types of Croup

While viral croup (also called laryngotracheobronchitis) is by far the most common type, there are other forms of croup that parents should be aware of:

• Spasmodic croup: This type comes on suddenly, often at night, without preceding cold symptoms. It tends to recur and may have an allergic component. Children with spasmodic croup often improve rapidly with exposure to cool air but may have recurrent episodes.
• Bacterial tracheitis: A rare but serious bacterial infection that can develop as a secondary infection following viral croup. It causes more severe symptoms and requires antibiotic treatment.

Historically, diphtheria was known as "true croup" or "membranous croup," while viral croup was called "false croup" or "pseudocroup." Thanks to widespread vaccination, diphtheria is now extremely rare in countries with robust immunization programs. Modern usage of "croup" almost always refers to the viral form of the disease.

What Are the Symptoms of Croup?

The hallmark symptoms of croup include a distinctive harsh, barking cough (often compared to a seal's bark), stridor (a high-pitched whistling or squeaking sound when breathing in), hoarseness, and varying degrees of breathing difficulty. Symptoms are characteristically worse at night and when the child is upset or crying.

Croup symptoms typically develop gradually over 12 to 48 hours, often starting with mild cold symptoms before progressing to the characteristic cough and breathing changes. Understanding the full range of symptoms and their progression helps parents know what to expect and when to become concerned.

The Classic Symptoms of Croup

Why Are Croup Symptoms Worse at Night?

One of the most characteristic features of croup is that symptoms dramatically worsen during evening and nighttime hours. This nocturnal pattern is so consistent that croup is sometimes called the "midnight disease." Several factors contribute to this pattern:

• Position: Lying down allows fluids and secretions to pool in the upper airway, increasing swelling
• Circadian rhythms: The body's natural cortisol levels (which help control inflammation) are lowest during nighttime hours
• Inflammatory patterns: The body's inflammatory response naturally peaks during the night
• Cooler air temperature: While cool air can actually help reduce swelling, the transition to cooler nighttime air can initially trigger airway reactivity
• Reduced distractions: Children are calmer during the day with more activities to distract them; at night, they focus more on their symptoms

Many parents describe being awakened suddenly by the alarming sound of their child's barking cough and struggling to breathe. While this can be terrifying, understanding that croup typically follows this pattern can help parents stay calm and respond appropriately.

Progression of Symptoms

Croup symptoms typically follow a predictable pattern:

• Days 1-2: Cold-like symptoms may develop, including runny nose, mild cough, and low-grade fever
• Day 2-3 (often evening/night): The characteristic barking cough and stridor appear, often suddenly. This is typically the peak of symptoms
• Days 3-5: Symptoms gradually improve, with the barking cough becoming less frequent and stridor resolving
• Days 5-7: Most children are significantly better, though a mild cough may persist for another week

Understanding Croup Severity

Healthcare providers classify croup into mild, moderate, and severe categories based on the presence and severity of specific symptoms. Understanding these distinctions helps parents gauge how urgently their child needs medical attention.

When Should You Seek Medical Care for Croup?

Seek immediate emergency care if your child has stridor at rest, severe difficulty breathing with chest retractions, blue or gray coloring around the lips or fingernails, extreme agitation or drowsiness, or drooling with inability to swallow. For milder symptoms that don't improve with home treatment within 30 minutes, contact your healthcare provider or seek urgent care.

Knowing when croup requires medical attention versus when it can be safely managed at home is one of the most important things for parents to understand. While most cases of croup are mild and resolve on their own, some children develop severe symptoms that require prompt medical intervention.

Signs That Require Urgent Medical Attention

Contact your healthcare provider, visit an urgent care center, or go to the emergency room if your child shows any of these signs:

• Stridor at rest: If you can hear the high-pitched breathing sound when your child is calm and sitting still (not just when crying or coughing), this indicates more significant airway narrowing
• Breathing doesn't improve: If symptoms don't improve after 15-30 minutes of home treatment measures (calm positioning, cool air exposure)
• Retractions: Visible pulling in of the skin between the ribs, above the collarbone, or at the notch of the throat with each breath
• Fast breathing: Respiratory rate consistently above 40 breaths per minute in a child over 1 year (or above 50 in infants)
• Unusual behavior: Child seems unusually irritable, lethargic, or unlike themselves
• Dehydration concerns: Child refuses to drink or has significantly decreased wet diapers
• High fever: Temperature above 39.4°C (103°F), which may suggest bacterial infection
• Symptoms lasting more than a week: Most croup improves within 3-5 days

When Home Treatment Is Appropriate

You can typically manage croup at home when:

• Your child has only occasional barking cough with no stridor at rest
• Symptoms improve when the child is calm and upright
• Your child is alert, interactive, and drinking fluids
• There are no significant retractions or labored breathing
• Your child is comfortable enough to sleep between coughing episodes

What to Expect When You Seek Medical Care

When you bring your child to a healthcare provider or emergency room for croup, the medical team will:

• Assess your child's breathing, including listening for stridor and watching for retractions
• Check oxygen levels using a pulse oximeter (a painless clip on the finger or toe)
• Evaluate overall appearance, including skin color and level of alertness
• Ask about symptom duration, progression, and any home treatments tried
• Usually diagnose croup based on clinical examination—X-rays are typically not needed

Treatment in a medical setting may include corticosteroids (most commonly dexamethasone), nebulized epinephrine for moderate to severe cases, and observation to ensure improvement. Most children with croup do not require hospitalization and can go home after treatment and a period of observation.

How Can You Treat Croup at Home?

Effective home treatment for mild croup includes keeping your child calm and comforted, positioning them upright, exposing them to cool moist air, ensuring adequate hydration, and using fever reducers if needed. Staying calm yourself is crucial—your anxiety can increase your child's distress, which worsens symptoms.

Most cases of croup can be successfully managed at home with simple, supportive measures. The primary goals of home treatment are to reduce airway swelling, keep the child calm (since agitation worsens symptoms), and maintain comfort while the viral infection runs its course.

Step-by-Step Home Treatment Guide

What About Steam?

For decades, parents were advised to sit in a steamy bathroom with their child or use hot steam vaporizers. However, current evidence does not support the effectiveness of steam therapy for croup. Several studies have found no significant benefit from humidity therapy, whether warm or cool.

Moreover, hot steam poses risks:

• Burn injuries from hot water or steam
• Hot air can sometimes worsen airway irritation
• No proven therapeutic benefit

Cool mist is preferred because it carries no burn risk and may help reduce inflammation. However, the most important aspect of the "steamy bathroom" approach is probably that it keeps the child calm and upright in a parent's lap—the positioning and comfort may matter more than the humidity.

What NOT to Do

• Don't use cough suppressants: Over-the-counter cough medicines are not effective for croup and are not recommended for young children
• Don't give honey to children under 1 year: While honey can soothe coughs in older children, it carries a risk of infant botulism in babies
• Don't use decongestants: Oral decongestants don't help croup and aren't recommended for young children
• Don't prop your child in a car seat for sleeping: This can create an unsafe sleeping position
• Don't smoke or allow smoking near your child: Smoke irritates the airways and worsens symptoms

What Medical Treatments Are Available for Croup?

Medical treatment for croup primarily involves corticosteroids (usually dexamethasone), which reduce airway inflammation and are effective for all severity levels. For moderate to severe cases, nebulized epinephrine provides rapid temporary relief by constricting blood vessels and reducing swelling. Severe cases may require oxygen therapy and hospital observation.

When home treatment isn't sufficient or symptoms are more severe, medical intervention can significantly improve outcomes and comfort for children with croup. The main treatments have been refined through decades of research and are highly effective when appropriately used.

Corticosteroids: The Cornerstone of Croup Treatment

Corticosteroids are the most important medical treatment for croup and are recommended for all children with croup who seek medical care, regardless of severity. These medications reduce inflammation in the airway, decreasing swelling and making breathing easier.

Dexamethasone is the most commonly used corticosteroid for croup because:

• A single dose is typically sufficient
• It can be given by mouth, which is less traumatic than injections
• Effects begin within 1-2 hours and last 24-48 hours
• It significantly reduces the need for hospitalization and return visits
• It's well-tolerated with minimal side effects at the doses used

The typical dose is 0.15-0.6 mg/kg, given as a single oral dose. For children who cannot tolerate oral medication or are vomiting, it can be given by injection. Studies have shown that even mild croup benefits from a single dose of dexamethasone, reducing symptom duration and the likelihood of seeking additional medical care.

Alternative corticosteroids include:

• Prednisolone: An oral corticosteroid that's an alternative when dexamethasone isn't available
• Budesonide: An inhaled corticosteroid that can be given by nebulizer, useful for children who can't tolerate oral medications

Nebulized Epinephrine: For Moderate to Severe Cases

Nebulized epinephrine (also called adrenaline) is used for children with moderate to severe croup, particularly those with stridor at rest or significant respiratory distress. It works by:

• Constricting blood vessels in the airway mucosa
• Rapidly reducing swelling and improving airflow
• Taking effect within minutes

The effects of nebulized epinephrine are dramatic but temporary, typically lasting 1-2 hours. This is why children who receive epinephrine are usually observed in the hospital or emergency department for at least 2-4 hours after treatment—to ensure symptoms don't return as the medication wears off and that the corticosteroids have had time to take effect.

Side effects of epinephrine can include increased heart rate and blood pressure, but these are usually mild and short-lived. The medication is very safe when used appropriately for croup.

Oxygen Therapy

Children with severe croup who have low oxygen saturation (below 92%) may need supplemental oxygen. This is typically delivered through a mask or nasal cannula. The need for oxygen usually indicates more severe disease and often leads to hospital admission for continued monitoring and treatment.

What About Antibiotics?

Croup is caused by viruses, not bacteria, so antibiotics are not helpful for treating the condition. Antibiotics do not work against viruses and will not speed recovery from croup. However, antibiotics may be prescribed if a bacterial complication develops, such as:

• Bacterial tracheitis (a serious secondary infection)
• Ear infection
• Pneumonia

Your healthcare provider will determine if antibiotics are needed based on clinical assessment.

Hospitalization

Most children with croup do not require hospitalization. However, admission may be necessary if:

• Symptoms don't improve with corticosteroids and epinephrine
• Multiple doses of epinephrine are needed
• Oxygen supplementation is required
• The child is too ill to drink fluids
• There are concerns about the family's ability to manage at home
• The child has underlying conditions that increase risk

In the hospital, children receive continued monitoring, scheduled treatments, and supportive care until symptoms improve enough for safe discharge home.

How Long Does Croup Last and What Is the Recovery Like?

Most cases of croup resolve within 3-7 days, with symptoms typically peaking on the second or third night and then gradually improving. The barking cough may persist for another week even after other symptoms have resolved. Children can usually return to daycare or school once they are fever-free for 24 hours and feel well enough for normal activities.

Understanding the typical course of croup helps parents know what to expect and when their child should be feeling better. While every child is different, most follow a fairly predictable pattern of illness and recovery.

The Typical Course of Croup

Croup generally follows this timeline:

• Days 1-2: Mild cold symptoms may develop (runny nose, slight cough, low fever). Some children go straight to croup symptoms without this prodrome.
• Days 2-3: The characteristic barking cough and stridor appear, usually worsening at night. This is typically when symptoms are most severe.
• Days 3-5: Symptoms begin to improve. The stridor resolves, and the cough becomes less frequent and less harsh-sounding.
• Days 5-7: Most children are feeling significantly better and can resume normal activities.
• Days 7-14: A residual cough may persist but is usually not the typical "barking" cough. The cough gradually fades.

When Can My Child Return to Daycare or School?

Children with croup can return to their normal activities, including daycare and school, when:

• They have been fever-free for at least 24 hours without fever-reducing medication
• They are eating and drinking normally
• They have enough energy to participate in normal daily activities
• They don't require frequent attention for coughing or breathing issues

Keep in mind that the viruses causing croup are contagious, typically for the first few days of illness or while fever is present. A mild residual cough is not usually a reason to keep children home, as they are no longer highly contagious at that point.

Will My Child Get Croup Again?

Some children seem prone to developing croup with viral infections, while others never experience it. Children who have had croup once are more likely to have it again with future respiratory viruses. This tendency usually decreases as the child gets older and their airways grow larger.

If your child has recurrent croup (frequent episodes with viral infections), your healthcare provider may:

• Prescribe corticosteroids to keep at home for future episodes
• Evaluate for underlying conditions that might contribute (such as allergies or anatomical variations)
• Provide a detailed action plan for managing future episodes

Possible Complications

Complications from croup are uncommon, especially with appropriate treatment. Potential complications include:

• Bacterial tracheitis: A rare but serious secondary bacterial infection that requires antibiotic treatment and often hospitalization
• Ear infection: The same viruses can spread to the middle ear
• Pneumonia: Viral or secondary bacterial pneumonia can develop in some cases
• Dehydration: From difficulty drinking or increased fluid losses with fever
• Respiratory failure: Extremely rare with modern treatment but possible in severe, untreated cases

Seek medical attention if your child's symptoms are not following the expected pattern of improvement, if new symptoms develop, or if you have any concerns about their recovery.

How Can You Prevent Croup?

While you cannot completely prevent croup since it's caused by common respiratory viruses, you can reduce risk through good hand hygiene, avoiding sick contacts, keeping up with vaccinations (especially for influenza), and avoiding tobacco smoke exposure. For children prone to croup, elevating the head during sleep when they catch a cold may help prevent symptoms.

Because croup is caused by common respiratory viruses that circulate widely in the community, completely preventing exposure is not realistic. However, several strategies can reduce your child's risk of developing croup or minimize symptom severity.

Hand Hygiene and Infection Control

The viruses that cause croup spread through respiratory droplets and contact with contaminated surfaces. Good hygiene practices can reduce transmission:

• Frequent handwashing: Teach children to wash hands thoroughly with soap and water, especially before eating, after using the bathroom, and after playing with others
• Avoid touching the face: Viruses often enter through the eyes, nose, and mouth
• Clean frequently touched surfaces: Doorknobs, toys, and electronic devices can harbor viruses
• Teach coughing/sneezing etiquette: Cover coughs and sneezes with elbow or tissue
• Keep sick children home: Reduces spread to other children

Vaccinations

While there is no vaccine specifically for the parainfluenza viruses that cause most croup cases, keeping your child's vaccinations current is still important:

• Influenza vaccine: Annual flu vaccination can prevent influenza-associated croup, which tends to be more severe
• DTaP vaccine: Includes protection against diphtheria, which historically caused severe croup-like illness
• Other routine vaccines: Keeping up with recommended vaccinations supports overall immune health

Avoid Tobacco Smoke

Children exposed to secondhand smoke have higher rates of respiratory infections and more severe symptoms when they do get sick. Smoking around children with croup worsens airway irritation and can prolong recovery. Creating a smoke-free environment for your child is one of the most important things you can do for their respiratory health.

Tips for Children Prone to Croup

If your child frequently develops croup with viral infections, these strategies may help minimize future episodes:

• Elevate the head of the bed: When your child catches a cold, proactively elevate the head of their bed by placing pillows under the mattress. This may help prevent airway swelling from worsening at night.
• Use a cool mist humidifier: Running a humidifier during cold and croup season can help keep airways moist
• Act early: At the first sign of croup symptoms, begin home treatment measures before symptoms escalate
• Have a plan: Discuss with your healthcare provider about having corticosteroids available at home for early treatment of future episodes