Whooping cough or Pertussis is an infectious disease that can be life threatening or fatal in infants but less serious in adults and adolescents.

The infection caused by a bacterium Bordetella pertussis, which spreads from the infected individual to others via mucus droplets in air released through bouts of coughing and sneezing. These are laden with the bacteria and infect the airways of the exposed.

Incubation period for whooping cough

It takes around seven days after the infection for the features of the disease to be apparent.

The time period is called incubation period.

The condition begins like common cold with congestion, runny nose, fever, sneezing and mild coughing bouts. After a week or two the coughing gets more severe.

Characteristic symptoms of whooping cough

Whooping cough is characterized by severe, violent bouts of coughing.

The cough comes over and over until it takes away the breath from the lungs leading to a forced inhalation that sounds like a “whoop”.

There may be a severe discharge of mucus from the mouth and nose.

The bouts leave the patient fatigued.

The spasms of coughing can go on for up to 10 weeks or more. In some places like China whooping cough is thus termed the “100 day cough”. (1, 2)

Stages of infection

The infection can be divided into three stages (3) –

1. The first week or two of the infection is called the Catarrhal stage – This is characterized by mild fever, runny nose and mild cough
2. The second stage may last 6 to 10 weeks and is called the Paroxysmal phase. This phase is characterized by the characteristic violent bouts of cough.
3. The third stage is the Convalescent or Recovery phase. This lasts for 2 to 3 weeks. In this the actual infection might be eliminated but the lungs are vulnerable to other infections. The cough decreases in severity and frequency but may come back if there are other infections.

Whooping cough in babies

Babies may cough less than older children but may develop vomiting along with coughing bouts.

They usually get the coughing fits after feeding and may go red or blue in the face.

The infants commonly suffer from apnoea or lack of air in their lungs. This may lead to sudden deaths in infants.

Death from pertussis occurs mostly (90% of cases) in unvaccinated infants less than 1 year old. Whooping cough needs to be excluded in cases of Sudden Infant Death Syndrome (SIDS). (1, 4)

Babies may also develop complications like pneumonia (lung infection), seizures or convulsions etc. that require hospitalization and emergency visits.

They may get infections like:

• sinusitis (infection of the sinuses)
• otitis media or middle ear infections
• other infections with bacteria or viruses
• nutritional deficiencies from continuous vomiting bouts
• seizures and neurological problems due to the lack of oxygen in the brain from apnoeic spells (1, 4)

Whooping cough in older patients

Older patients may develop bronchiectasis or broadening of the airways. Later in life this can lead to further lung complications.

Bouts of coughing may also lead to nose bleedings or epistaxis in some patients.

The force of the cough may also cause bleeding spots over the whites of the eyes called subconjunctival hemorrhages. (5)