Pertussis Clinical Presentation

Updated: Jan 18, 2023
  • Author: Joseph J Bocka, MD; Chief Editor: Russell W Steele, MD  more...
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Typically, the incubation period of pertussis ranges from 3-12 days. Pertussis is a 6-week disease divided into catarrhal, paroxysmal, and convalescent stages, each lasting from 1-2 weeks.

Older children, adolescents, and adults may not exhibit distinct stages. Symptoms in these patients include uninterrupted coughing, feelings of suffocation or strangulation, and headaches. Vaccinated adults usually develop only prolonged bronchitis without a whoop, whereas unvaccinated adults are more likely to have whooping and posttussive emesis.

Stage 1 - Catarrhal phase

The initial (catarrhal) phase is indistinguishable from common upper respiratory infections. It includes nasal congestion, rhinorrhea, and sneezing, variably accompanied by low-grade fever, tearing, and conjunctival suffusion. Pertussis is most infectious when patients are in the catarrhal phase, but pertussis may remain communicable for 3 or more weeks after the onset of cough.

Stage 2 - Paroxysmal phase

Patients in the second (paroxysmal) phase present with paroxysms of intense coughing lasting up to several minutes. In older infants and toddlers, the paroxysms of coughing occasionally are followed by a loud whoop as inspired air goes through a still partially closed airway. Infants younger than 6 months do not have the characteristic whoop but may have apneic episodes and are at risk for exhaustion. Posttussive vomiting and turning red with coughing are common in affected children.

Stage 3 - Convalescent phase

Patients in the third (convalescent) stage have a chronic cough, which may last for weeks.


Physical Examination

In patients with uncomplicated pertussis, physical examination findings contribute little to the diagnosis. In all patients with pertussis, fever is typically absent. Most patients do not have signs of lower respiratory tract disease. Conjunctival hemorrhages and facial petechiae are common and result from intense coughing. Dehydration also is common on presentation. Hypoxia should be considered and assessed.

The classic inspiratory gasp or whoop develops primarily in children aged 6 months to 5 years. It usually is absent in patients younger than 6 months and in most older vaccinated children and adults. However, it often can be observed in unvaccinated adults, as can posttussive emesis.