Croup vs. whooping cough

Both croup and whooping cough can start like a cold, with symptoms of runny nose, cough, fever, red, watery eyes and nasal congestion for the first seven to 10 days.

As symptoms worsen, both whooping cough and croup affect the respiratory system with inflammation and drainage, which cause coughing. The Centers for Disease Control and Prevention reports a recent peak in whooping cough since 2012, with 48,277 cases in that year. Croup affects approximately 3% of children per year.

There are a few distinctive ways you can tell the difference between croup and whooping cough.

What is croup?

Croup is characterized by inflammation of the vocal cords and the trachea, leading to breathing difficulties, a hoarse throat and a barking cough occurring after one or two days of cold symptoms. In addition to the cough, breathing can be high-pitched and noisy, especially at night. Croup is usually caused by the parainfluenza virus in approximately 75% of croup cases and tends to be more common in the fall and winter.

Children ages 6 months to 3 years have the highest risk for croup, and the risk increases if you have a family history of croup. You may see rapid, labored, shallow breathing with a child's nostrils flaring, and you may see their ribs each time they take a breath. Many cases of croup can be managed at home with pain medications and cool or warm mist to loosen secretions. The severity of croup is described as:

• Mild: A barking cough without stridor (high-pitched, wheezing sound where vocal cords and trachea blockages disrupt airflow).
• Moderate: Stridor at rest, mild retractions of the chest when breathing and symptoms of respiratory distress.
• Severe: Significant stridor at rest, severe chest retractions, agitation, fatigue and paleness. See your child's healthcare provider if they have signs of respiratory distress with decreased or absent breath sounds, lips that are a bluish color or decreased alertness.

What is whooping cough?

Pertussis (whooping cough) is known for the "whooping" sound made when someone gasps for air after a coughing fit. The Bordetella pertussis bacteria causes whooping cough. This respiratory tract infection is highly contagious and occurs in the trachea as well as the lungs. It has been called the "100-day cough," as the infection can last over 10 weeks. Symptoms develop about 5–10 days after exposure to pertussis.

Whooping cough is divided into three stages:

• Catarrhal stage: Symptoms are similar to a viral respiratory infection, with a mild, occasional cough, low-grade fever and runny nose lasting one to two weeks.
• Paroxysmal stage: Coughing increases in severity, with a long series of coughs causing gagging or vomiting and struggling for breath, resulting in cyanosis (blue-colored skin from inadequate oxygenation of the blood). The symptoms of a whooping noise after a coughing attack may not always occur. This stage lasts two to eight weeks.
• Convalescent stage: The cough slowly subsides with episodes of coughing recurring or worsening over several weeks to months. A study reports the median duration of cough in children was 112 days, with a range of 38–191 days.

If a baby under 1 year old gets whooping cough, about 50% will require hospitalization. If not treated, whooping cough can lead to pneumonia, seizure, brain damage and death.

Antibiotics are the usual treatment to control symptoms and shorten the amount of time a person is contagious. Treating whooping cough early may decrease how serious the infection becomes. If it is treated after three weeks with antibiotics, there may not be an effect on the progression of symptoms. The cough is coming from localized damage of upper respiratory tissues, not the infection, and it can take many weeks to regrow affected tissues before the cough subsides. The highest risk of transmitting the disease is also during the first three weeks.

Your healthcare provider may recommend or prescribe a cough suppressant, but opioids should be avoided because the risk of addiction outweighs the benefit. Home remedies that may provide some relief are using a mist vaporizer, drinking extra fluids and avoiding allergens, smoke or chemicals that may trigger a cough.

Croup vs. whooping cough

This chart shows some of the differences between croup and whooping cough:

How do vaccinations help?

Vaccines protect communities from the spread of disease. There is no vaccine for croup. There is a vaccination for whooping cough. Before vaccines were available in the 1940s, about 200,000 children contracted whooping cough and 9,000 children died. Now there are about 10,000–40,000 cases and 20 deaths per year due to whooping cough. If people stop getting vaccinated, a rapid rise of specific diseases could cause thousands to get sick and die.

Children under age 10 were predominately affected by whooping cough before vaccines were available. Now over 50% of whooping cough cases are in unvaccinated adolescents and adults, who are passing the infection on to unvaccinated infants and children. Parents should make sure older adults coming into contact with their infants have been vaccinated for whooping cough.

There are two vaccines available that protect against whooping cough: the DTaP vaccine and the Tdap vaccine, which also protects against tetanus and diptheria. The DTaP vaccine protects babies and younger children, and the Tdap vaccine protects preteens, teens and adults, including pregnant women. Getting the vaccine during pregnancy helps protect unborn babies from whooping cough until they're old enough to receive the DTaP vaccine at 2 months old.

Beyond vaccination, there are two basic things everyone in the family can do to prevent the spread of either croup or whooping cough.

• Wash your hands using soap and water or alcohol-based rubs after touching nasal secretions
• Cover your nose and mouth with a tissue or upper shirt sleeve when coughing or sneezing

Clinically reviewed and updated July 2021.