History and exam

Key diagnostic factors

common

cough

Seen in almost all patients, beginning at 1-2 weeks after infection; may persist for weeks to months.[10] CDC: pertussis (whooping cough) Opens in new window

Some infants have atypical disease and initially have apneic spells with only minimal cough or other respiratory symptoms.

inspiratory whooping

Patients may report paroxysmal coughing ending in a high-pitched inspiratory whoop, typically beginning in the second week of illness and persisting for 1-6 weeks. Frequently absent in adolescents and adults.[10] CDC: pertussis (whooping cough) Opens in new window

coryza

Rhinorrhea, sneezing, a nonspecific mild cough, and low-grade fever may be present in the early (catarrhal) stage of disease (1-2 weeks after infection).[10]

posttussive vomiting

Paroxysms of coughing may end with gagging or emesis. Most common in children.

Other diagnostic factors

uncommon

apnea

Infants may present with apnea, with or without cough.

neurologic complications

Seizures and encephalopathy occur primarily in young infants and may be caused by hypoxia or bacterial toxins.[2]​​[10]

Risk factors

strong

unvaccinated or undervaccinated status

Unvaccinated or undervaccinated people have an increased risk of contracting pertussis and of severe disease.[11] Natural infection and immunization, however, do not provide long-term immunity. One model suggests that, in children and adolescents, the initial protective efficacy of 85% to 90% for Tdap vaccine falls by approximately 10% per year.[13] In another study, overall vaccine efficacy in adolescents who received acellular pertussis vaccines fell from 64% to 34% 2-4 years after vaccination.[14] Waning immunity is primarily responsible for the persistence of pertussis in school-age children and older individuals.[10]

close contact with an infected person, especially in the household

Humans are the only host of Bordetella pertussis.[2]​​[10] Transmission occurs primarily via large respiratory droplets generated by coughing or sneezing, mostly in the catarrhal stage of the illness, and can also occur through airborne particles.​​[1] ​Up to 80% of close contacts of infected individuals may develop pertussis. Studies suggest that immediate household contacts are primarily responsible for the transmission of infection to infants.[15][16]

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