What is it?
Whooping cough (pertussis) is a highly contagious respiratory tract infection. In advanced stages, it's marked a severe, hacking cough followed by a high-pitched intake of breath that sounds like "whoop."
In the first half of the 20th century, whooping cough was a leading cause of childhood illness and death in the United States. But after the introduction of a vaccine, the number of cases gradually declined, reaching a low in the mid-1970s.
Since then, however, the incidence of whooping cough has been increasing, primarily among children too young to have completed the full course of vaccinations and teenagers and adults whose immunity has faded.
Once you become infected with whooping cough, it takes three to 12 days for signs and symptoms to appear. They're usually mild at first and resemble those of a common cold:
- Runny nose
- Nasal congestion
- Red, watery eyes
- A mild fever
- Dry cough
After a week or two, signs and symptoms worsen. Severe and prolonged coughing attacks may:
- Bring up thick phlegm
- Provoke vomiting
- Result in a red or blue face
- Cause extreme fatigue
- End with a high-pitched "whoop" sound during the next breath of air
However, many people — particularly infants, adolescents and adults — don't develop the characteristic whoop. Sometimes, a persistent hacking cough is the only sign that an adolescent or adult has whooping cough.
Whooping cough is caused by bacteria. When an infected person coughs or sneezes, tiny germ-laden droplets are sprayed into the air and breathed into the lungs of anyone who happens to be nearby.
Once inside your airways, the bacteria multiply and produce toxins that interfere with your respiratory tract's ability to sweep away germs. Thick mucous accumulates inside your airways, causing uncontrollable coughing.
The bacteria also cause inflammation that narrows breathing tubes in your lungs. This narrowing leaves you gasping for air — sucking in air with a high-pitched "whoop" — after a fit of coughing.
Whooping cough is thought to be on the rise for two main reasons. The whooping cough vaccine you receive as a child eventually wears off, leaving most teenagers and adults susceptible to the infection during an outbreak — and there continue to be regular outbreaks. In addition, children aren't fully immune to whooping cough until they've received at least three shots, leaving those 6 months and younger at greatest risk of contracting the infection.
Most people recover from whooping cough with no problems. When complications occur, they tend to be side effects of the strenuous coughing, such as:
- Bruised or cracked ribs
- Abdominal hernias
- Broken blood vessels in the skin or the whites of your eyes
In infants — especially those under 6 months of age — complications from whooping cough are more severe and may include:
- Ear infections
- Slowed or stopped breathing
- Brain damage
Because infants and toddlers are at greatest risk of complications from whooping cough, they're more likely to need treatment in a hospital. Complications can be life-threatening for infants less than 6 months old.
Diagnosing whooping cough in its early stages can be difficult because the signs and symptoms resemble those of other common respiratory illnesses, such as a cold, the flu or bronchitis.
Sometimes, doctors can diagnose whooping cough simply by asking about symptoms and listening to the cough. Medical tests may be needed to confirm the diagnosis. Such tests may include:
- A nose or throat culture and test. Your doctor takes a nose or throat swab or suction sample. The sample is then sent to a lab and cultured or otherwise tested for whooping cough bacteria.
- Blood tests. A blood sample may be drawn and sent to a lab to check for a high white blood cell count. White blood cells help the body fight infections, such as whooping cough. A high white blood cell count typically indicates the presence of infection or inflammation. This is a general test and not specific for whooping cough, however.
- A chest X-ray. Your doctor may order an X-ray to check for the presence of inflammation or fluid in the lungs, which can occur when pneumonia complicates whooping cough and other respiratory infections.