Executive summary
- Think pertussis in a prolonged cough illness with paroxysms, inspiratory whoop, post-tussive vomiting, or apnoea in infants.
- Early antibiotics have two roles: they may modestly modify the illness if started early, but more importantly they reduce transmission to vulnerable contacts.
- Infants are the high-risk group: low threshold for paediatric assessment if feeding, apnoea, cyanosis, respiratory effort, or hydration are concerning.
Clinical pattern and diagnosis
- Three phases are typical: catarrhal, paroxysmal, and convalescent. The early catarrhal phase may look like a routine URTI before the characteristic cough appears.
- Classic features: repeated coughing bouts, inability to catch breath, inspiratory whoop, post-tussive vomiting, facial congestion, and prolonged recovery.
- PCR testing is most useful early in the illness; diagnosis becomes more clinical later on.
Treatment and public-health thinking
- If onset of cough is within the previous 14 days, offer antibiotic treatment if the person does not need admission.
- If there is a household or other close contact at high risk of severe disease, antibiotics may still be indicated later in the illness because transmission prevention becomes the key aim.
- Pregnancy and infancy alter drug choice: NICE CKS specifically advises erythromycin in pregnancy, while clarithromycin is preferred for infants under 1 month.
- Remember notification/public-health steps and advise on reducing spread, especially around infants and pregnancy.
Frequently asked questions
When are antibiotics most useful?
NICE CKS advises treatment if cough onset was within the previous 14 days, and later if there are high-risk close contacts where reducing onward transmission matters.
What makes pertussis dangerous in babies?
Infants may present with apnoea, colour change, poor feeding, dehydration, or significant respiratory compromise rather than a classic dramatic whoop, so the threshold for escalation should be low.
Does a normal early coryzal phase exclude pertussis?
No. The catarrhal phase often looks like a standard viral URTI before the paroxysmal cough pattern becomes obvious.
Transparency
This page is an educational, clinician-written summary of publicly available NICE guidance intended for trained healthcare professionals. It uses original wording (not copied text) and should be used alongside the full NICE source, local pathways, and clinical judgement. Doses provided are for general reference; always check the BNF/SPC.