7 Key Croup Symptoms Every Parent Should Know

Croup is a common respiratory condition that primarily affects young children, typically between the ages of 6 months and 3 years. This viral infection causes swelling in the upper airway, specifically around the vocal cords and windpipe, leading to distinctive breathing difficulties and a characteristic barking cough sound that many parents find alarming. Understanding the symptoms of croup is crucial for early recognition and appropriate care.

While croup can be frightening to witness, especially during nighttime episodes, most cases are mild and can be managed at home with proper guidance. However, knowing the warning signs that require medical attention is essential for every parent and caregiver. This comprehensive guide will walk you through the key symptoms of croup, helping you identify this condition and understand when to seek medical help.

1. Barking Cough – The Hallmark Symptom

The most distinctive and recognizable symptom of croup is the barking cough, often described as sounding like a seal or a dog barking. This unique cough develops due to inflammation and swelling in the larynx (voice box) and trachea (windpipe), which narrows the airway and changes how air passes through.

The barking cough in kids typically:

• Starts suddenly, often during the night
• Sounds harsh, loud, and metallic
• Worsens when the child is crying or agitated
• May come in episodes or fits
• Often intensifies during nighttime hours

While barking cough is most common in children, barking cough in adults can occasionally occur, though it’s much rarer. When adults develop croup, the symptoms are generally milder due to their larger airways. Parents who hear this distinctive cough sound for the first time often describe it as alarming and unforgettable – once you’ve heard the croup cough sound, you’ll likely recognize it immediately if it occurs again.

2. Stridor – The High-Pitched Breathing Sound

Stridor is a high-pitched, whistling or squeaking sound that occurs when breathing in (inspiration). This symptom develops because the inflamed, swollen airway creates turbulent airflow as air passes through the narrowed passage. Stridor is one of the most medically significant symptoms of croup because it indicates the degree of airway obstruction.

Key characteristics of stridor in croup include:

• Most noticeable when the child breathes in
• Can be heard without a stethoscope in moderate to severe cases
• May only occur during coughing fits in mild cases
• Becomes constant and present even at rest in severe cases
• Often more pronounced when the child is upset, crying, or active

The presence and severity of stridor helps healthcare providers assess how serious the croup episode is. Stridor that only occurs during crying or coughing typically indicates mild croup, while stridor present even when the child is calm and resting suggests more significant airway narrowing that may require medical intervention.

3. Hoarse Voice or Cry

Voice changes are a common and early symptom of croup. Children with croup typically develop a hoarse, raspy voice or cry due to inflammation of the vocal cords. This symptom often appears before the characteristic barking cough develops, making it an important early warning sign.

The hoarseness in croup:

• Develops gradually over the first day or two of illness
• Makes the child’s voice sound rough, strained, or weak
• Is particularly noticeable when the child cries or tries to speak
• May progress to near loss of voice in some cases
• Usually accompanies other respiratory symptoms

Parents might first notice their child’s voice sounds different when they wake up in the morning or during typical daily activities. The hoarseness results from the same inflammation affecting the larynx that causes the barking cough, but this symptom can be present even during the quieter moments between coughing episodes.

4. Labored or Difficult Breathing

Respiratory distress is a critical symptom to monitor in children with croup. As the airways become more swollen and narrowed, children must work harder to breathe, which manifests as labored breathing. This symptom ranges from mild difficulty to severe distress requiring immediate medical attention.

Signs of labored breathing in croup include:

• Rapid breathing (tachypnea) with faster than normal respiratory rate
• Retractions – visible pulling in of the skin between the ribs, above the collarbone, or below the ribcage with each breath
• Nasal flaring – widening of the nostrils with breathing efforts
• Use of accessory muscles – neck and chest muscles working visibly to help breathing
• Difficulty completing sentences or feeding due to breathlessness
• Agitation or restlessness from breathing discomfort

The breathing difficulty in croup typically worsens at night and may improve somewhat during the day. This pattern occurs because lying flat can increase airway swelling, and cool night air exposure when moving between rooms can sometimes temporarily relieve or worsen symptoms. Parents should carefully monitor their child’s breathing pattern and seek immediate medical care if breathing becomes severely labored or if the child appears to be struggling significantly to get air.

5. Fever

Fever is a common accompanying symptom of croup, though it’s typically low-grade to moderate rather than high. Since croup is most often caused by viral infections, fever represents the body’s immune response to the invading pathogen.

Fever patterns in croup:

• Usually ranges from 100°F to 104°F (37.8°C to 40°C)
• Often appears as one of the first symptoms, before the cough develops
• May be absent in milder cases
• Typically lasts 2-3 days
• Can contribute to the child’s overall discomfort and irritability

While fever itself is not usually dangerous in croup, it can make children more uncomfortable and potentially worsen breathing difficulties by increasing metabolic demands. The fever also helps distinguish croup from non-infectious causes of stridor. Very high fevers (above 104°F or 40°C) are uncommon in typical viral croup and might suggest a bacterial complication or different diagnosis.

6. Cold-Like Symptoms

Croup typically begins with symptoms resembling a common cold, as the same viruses that cause colds are often responsible for croup. These initial symptoms may appear 1-3 days before the characteristic barking cough and stridor develop.

Common cold-like symptoms preceding croup include:

• Runny or stuffy nose with clear to cloudy nasal discharge
• Mild sore throat or throat discomfort
• Sneezing
• Decreased appetite
• General malaise or feeling unwell
• Watery eyes
• Mild headache in older children

These early symptoms are often indistinguishable from a typical upper respiratory infection, which is why parents may not initially suspect croup. However, as the infection progresses deeper into the larynx and trachea, the distinctive croup symptoms emerge. Recognizing that croup often follows this pattern can help parents anticipate and prepare for potential nighttime coughing episodes, especially if their child has had croup before.

7. Worsening Symptoms at Night

A characteristic feature of croup is that symptoms typically intensify during nighttime hours. Many children may seem relatively comfortable during the day, only to wake suddenly at night with severe barking cough and breathing difficulty. This pattern is so common that it’s considered a defining feature of croup.

Why croup symptoms worsen at night:

• Lying flat increases blood flow to the upper airway, potentially increasing swelling
• Natural circadian rhythms affect inflammatory responses and airway resistance
• Cortisol levels drop at night, reducing the body’s natural anti-inflammatory response
• Cooler air temperatures at night may trigger airway reactivity
• Accumulated secretions during sleep can further narrow airways

The nighttime worsening typically occurs suddenly, with children often waking abruptly from sleep with severe coughing and stridor. Parents describe their child going from seemingly fine at bedtime to significant respiratory distress within hours. Episodes commonly occur between 10 PM and 4 AM. This predictable pattern means parents of children with croup should be prepared for potential nighttime episodes and know when to seek emergency care. Fortunately, symptoms typically improve again in the morning hours, though this day-night cycle may repeat over several nights as the illness runs its course.

Main Causes of Croup

Understanding what causes croup can help parents recognize risk factors and understand why this condition is contagious. Croup is primarily caused by viral infections, though the specific pathogens can vary.

Viral Causes:

• Parainfluenza viruses: The most common cause, responsible for approximately 75% of croup cases, particularly parainfluenza virus types 1 and 2
• Influenza A and B: Can cause more severe cases of croup, especially during flu season
• Respiratory syncytial virus (RSV): Another common culprit, particularly in younger infants
• Adenoviruses: Can cause croup along with other respiratory symptoms
• Rhinoviruses: The common cold viruses occasionally lead to croup
• Measles virus: Rare in vaccinated populations but can cause severe croup
• Coronaviruses: Including SARS-CoV-2, have been associated with croup-like symptoms

Why Children Are More Susceptible:

• Smaller airways that swell more easily and become obstructed with less inflammation
• Less developed immune systems with less prior viral exposure
• Softer, more collapsible airway structures
• Peak incidence between 6 months and 3 years when airways are proportionally smallest

Is Croup Contagious?

Yes, croup is contagious because it’s caused by viruses that spread from person to person. The viruses spread through:

• Respiratory droplets when an infected person coughs or sneezes
• Direct contact with contaminated surfaces followed by touching the face
• Close personal contact with infected individuals

The contagious period typically begins a day or two before symptoms appear and continues for about 3 days after symptoms start, though viruses can sometimes be shed for longer. Children are most contagious during the first few days of illness when cold-like symptoms are present.

Prevention Strategies

While it’s not always possible to prevent croup entirely due to its viral nature, several strategies can reduce the risk of infection and transmission:

Hand Hygiene:

• Teach children to wash hands frequently with soap and water for at least 20 seconds
• Use hand sanitizer when soap and water aren’t available
• Wash hands before eating, after using the bathroom, and after coughing or sneezing
• Clean hands after touching common surfaces in public places

Respiratory Etiquette:

• Teach children to cover coughs and sneezes with a tissue or elbow, not hands
• Dispose of used tissues immediately
• Avoid touching the face, especially nose, mouth, and eyes

Avoiding Exposure:

• Keep children away from people who are sick with respiratory infections
• Avoid crowded places during peak cold and flu season when possible
• Keep sick children home from daycare or school to prevent spread
• Limit sharing of toys, utensils, cups, and other personal items

Vaccination:

• Keep children up to date on recommended vaccinations, including influenza vaccine
• Ensure measles, mumps, and rubella (MMR) vaccination is current
• Consider the COVID-19 vaccine as recommended for age groups

Environmental Measures:

• Regularly clean and disinfect frequently touched surfaces
• Ensure good ventilation in indoor spaces
• Avoid exposing children to secondhand smoke, which can irritate airways and increase susceptibility to respiratory infections
• Maintain good overall health through adequate sleep, nutrition, and hydration

For Families with Croup History:

• Some children are more prone to recurrent croup episodes
• Keep a cool-mist humidifier ready for use during episodes
• Know when to seek medical care and have an action plan
• Be extra vigilant during fall and early winter when croup is most common

Frequently Asked Questions

What is croup exactly?

Croup is a viral respiratory infection that causes inflammation and swelling of the larynx (voice box), trachea (windpipe), and bronchi (airways leading to the lungs). This swelling narrows the airway, leading to the characteristic barking cough, hoarse voice, and difficulty breathing, especially in young children.

How can I recognize the croup cough sound?

The croup cough sound is distinctive and often described as a harsh, barking cough that resembles a seal’s bark or a dog barking. It has a metallic, resonant quality that’s quite different from a regular cough. Many parents say once you’ve heard it, you’ll never forget it.

Is croup contagious to adults?

Yes, the viruses that cause croup are contagious to people of all ages. However, adults who contract these viruses typically develop common cold symptoms rather than croup because their larger airways are less likely to become significantly narrowed by the inflammation.

When should I take my child to the emergency room for croup?

Seek immediate emergency care if your child has: difficulty breathing or rapid breathing at rest, stridor (high-pitched breathing sound) when calm and resting, severe retractions (skin pulling in around ribs and neck), bluish or grayish skin color around the lips or fingernails, drooling or difficulty swallowing, inability to cry or speak due to breathing difficulty, extreme agitation or fatigue, or if you’re concerned about their breathing.

How long does croup typically last?

Most cases of croup last 3-7 days, with symptoms typically peaking around days 2-3. The barking cough and stridor usually improve after 2-3 days, though a regular cough may persist for up to a week. Nighttime symptoms are most common during the first 2-3 nights of illness.

Can my child get croup more than once?

Yes, children can get croup multiple times because it’s caused by several different viruses, and having one type doesn’t provide immunity to others. Some children are more prone to recurrent croup and may experience it several times during their early childhood years. Most children outgrow the tendency to develop croup by age 5-6 as their airways grow larger.

Does cold air really help with croup symptoms?

Cool, moist air may provide temporary relief for some children with croup by reducing airway inflammation and swelling. This is why some parents find that taking their child outside in cool night air or into a steamy bathroom provides relief. However, this is a temporary measure and doesn’t treat the underlying infection. Medical advice should be sought for proper management.

Can croup occur in adults?

While rare, adults can develop croup-like symptoms including a barking cough. Adult croup is uncommon because adult airways are larger and less likely to become significantly narrowed by viral inflammation. When adults do experience these symptoms, they’re typically milder than in children.

Is there a difference between croup and whooping cough?

Yes, these are completely different conditions. Croup is caused by viruses and produces a barking cough, while whooping cough (pertussis) is caused by bacteria and produces a distinctive “whoop” sound after coughing fits. Whooping cough is more serious, lasts longer (weeks to months), and is preventable through vaccination.

What time of year is croup most common?

Croup is most common during fall and early winter months, typically from October through March in the Northern Hemisphere. This seasonal pattern coincides with the peak activity of parainfluenza viruses, the most common cause of croup.

References:

• Mayo Clinic – Croup
• Centers for Disease Control and Prevention – Parainfluenza
• NHS – Croup
• Children’s Hospital of Philadelphia – Croup
• MedlinePlus – Croup