Synopsis
Recognise age-dependent pertussis, protect young infants from apnoea and deterioration, select testing by cough duration, give timely eradication treatment, notify and manage exclusion and contacts with UKHSA, and use vaccination to prevent severe disease.
- Pertussis begins with a catarrhal phase resembling a cold, then develops paroxysms of repeated cough, inspiratory whoop, post-tussive vomiting and exhaustion; cough commonly lasts 6–8 weeks or longer.
- Infants may present with apnoea, cyanosis, poor feeding or bradycardia and no whoop. Adolescents and vaccinated children may have prolonged nonspecific cough.
- Suspect pertussis with cough lasting 2 weeks or more plus paroxysms, whoop or post-tussive vomiting, or earlier when epidemiology or infant apnoea is compatible.
- First-line confirmation early in illness is a properly obtained nasopharyngeal sample for PCR according to age and time since cough onset. Culture has highest specificity but sensitivity falls after antibiotics and time.
- UKHSA testing changes with age and duration; later illness may use oral-fluid antibody or serology in defined age groups. Follow the current testing algorithm rather than sending every modality.
- Pertussis is notifiable on clinical suspicion in England; do not wait for laboratory confirmation before notification or action around a vulnerable infant.
- Offer an appropriate macrolide within 21 days of cough onset to eradicate carriage and reduce transmission. Antibiotics given after the paroxysmal phase begins often do not shorten the cough.
- Current UKHSA regimens include clarithromycin 7.5 mg/kg twice daily for 7 days in neonates and children under 8 kg; weight-banded doses apply above 8 kg. Verify the current BNF-C and UKHSA table.
- Azithromycin 10 mg/kg once daily for 3 days is an alternative from infancy, maximum 500 mg above 6 months; macrolides require interaction and QT-risk review.
- Exclude from school, childcare or communal residential areas until 48 hours after appropriate antibiotics begin, or 21 days from cough onset if untreated.
- Health protection, not the individual prescriber alone, determines chemoprophylaxis and vaccination for eligible close contacts according to exposure timing and vulnerability.
- Prevent severe infant disease through maternal pertussis vaccination in every pregnancy, normally around 20 weeks and ideally before 32 weeks, plus on-time infant vaccines at 8, 12 and 16 weeks and later boosters.
Key red flags
Any apnoea, cyanosis, bradycardia, seizure, reduced consciousness or exhaustion in an infant requires urgent hospital assessment.
Age under 6 months carries the greatest morbidity and mortality; absence of a whoop does not reduce risk.
Poor feeding, repeated post-tussive vomiting, dehydration or weight loss may require admission and feeding support.
Tachycardia, marked tachypnoea, hypoxaemia, pneumonia or a very high lymphocyte count can accompany severe infant pertussis and pulmonary hypertension.
Haemoptysis, focal neurology, persistent fever or focal chest signs requires evaluation for complications or an alternative diagnosis.
A suspected case with household contact with a pregnant person or incompletely vaccinated infant needs prompt health-protection risk assessment.
Investigation priorities
Confirm infection using the current UKHSA algorithm without delaying notification.
Management branches
A compatible cough or infant apnoea syndrome is identified.
- Assess age-specific severity and admit young or physiologically compromised infants.
- Notify on clinical suspicion and collect the test recommended for age and cough duration.
- Record cough onset and vulnerable contacts and begin infection-control measures without awaiting the result.