Whooping cough is a respiratory tract infection caused by Bordetella pertussis, a gram-negative bacteria. It causes coughing fits so severe that the child cannot inhale between coughs, resulting in a distinctive whooping sound as they forcefully draw in the air afterwards.
Bordetella pertussis is infectious for the first three weeks of the illness. Whooping cough can affect people of all ages.
Children and pregnant women are vaccinated against pertussis. When the vaccine is given in pregnancy, the mother’s antibodies cross the placenta and help protect the newborn. The protection from the vaccine decreases over time.
Presentation
The approximate timeline for whooping cough (with significant variation):
- The incubation period lasts around 1 week
- Coryzal symptoms lasting around 1 week (e.g., blocked and runny nose, sore throat and mild dry cough)
- Severe paroxysmal cough lasting 1-10 weeks
- Recovery over 2-3 weeks
These severe coughing attacks happen suddenly and repeatedly, with periods of no coughing in between, which is known as a paroxysmal cough. The cough may be more frequent at night. The fits can be so intense that the patient runs out of breath, and when the coughing stops, a loud, high-pitched whoop is usually heard as they breathe in. Not all patients will produce the whooping sound. Infants with pertussis may develop apnoea (pauses in breathing).
In some cases, the coughing is so forceful that it may cause:
- Fainting
- Vomiting
- Subconjunctival haemorrhage
- Facial petechiae
- Pneumothorax
- Rib fractures
- Hernias
- Intervertebral disc herniation
Diagnosis
A nasopharyngeal or nasal swab with PCR testing or bacterial culture can confirm the diagnosis within 3 weeks of the onset of symptoms.
Where the cough has been present for more than 2 weeks, and they have not been vaccinated in the past year, patients can be tested for the anti-pertussis toxin immunoglobulin G. These are antibodies created by the immune system in response to the pertussis toxin. They can be tested for in a sample of oral fluid or blood.
Management
Pertussis is a notifiable disease, and the UK Health Security Agency (UKHSA) must be notified of all suspected and confirmed cases. Vulnerable or acutely unwell patients (e.g., under 6 months or apnoeas) may need admission. Preventing the spread is important. Patients should avoid contact with vulnerable people, dispose of tissues, and maintain hand hygiene.
NICE CKS (2024) recommends that patients need to stay off nursery, school or work until either:
- Taking 48 hours of antibiotics
- 14 days from the onset of the cough (or 21 days for higher-risk work, such as caring for infants or pregnant women)
Antibiotics are started when the cough onset is within 14 days (or 21 days if they have contact with vulnerable infants). The options are:
- Macrolides first-line (e.g., azithromycin, erythromycin and clarithromycin)
- Co-trimoxazole
Prophylactic antibiotics (macrolides first-line) are recommended for close contacts in priority groups, for example:
- Unvaccinated infants
- Pregnant women over 32 weeks gestation
- People who have close contact with infants or pregnant women
Prognosis
The symptoms typically resolve within 8 weeks but can last many months. It is also known as the “100-day cough” due to the potentially long duration of the cough.
A long-term complication of whooping cough is bronchiectasis, which involves permanent dilation of the bronchi and recurrent respiratory infections.
Last updated February 2025
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