Reasoning GP · Algorithm · 1-page summary
Acute cough
For: adults with cough <3 weeks, face to face or remote, in hours or OOH; infant and child red flags included. Not for: cough >8 weeks (use the chronic cough algorithm). Children: use age-specific respiratory rates and NICE fever, bronchiolitis and croup guidance.
Core rule: most acute cough is viral and lasts 3–4 weeks, so no routine antibiotic. Your job is to find the sepsis, pneumonia, PE, airway emergency or cancer hiding in it. CRB-65 supports, never replaces, judgement.
0Stop — call 999 now — do not delay transfer
- Unstable: severe or worsening hypoxaemia with distress, altered mental state or compromise; suspected high-risk sepsis → 999
- Suspected PE with haemodynamic instability, or tension pneumothorax (severe breathlessness with tracheal deviation or unilateral absent breath sounds) → 999
- Stridor at rest, drooling or rapidly progressive airway symptoms, any age → 999. Position of comfort; do not force supine; no throat examination.
- Infant with apnoea, cyanosis or severe breathing difficulty (pertussis may show no whoop) → 999
1Triage pneumonia by CRB-65 — with judgement (NG250)
1 point each: Confusion · RR ≥30 · BP systolic <90 or diastolic ≤60 · age ≥65
| Score | Action — comorbidity, frailty, SpO₂, oral intake or support can upgrade any score |
|---|---|
| 0 | Low risk (<1%) → usually community care |
| 1 | Individualise: primary care, virtual ward, SDEC, hospital at home |
| 2 | Consider hospital referral → Same-day |
| 3–4 | High risk (>10%) → hospital; 999 if unstable |
2Screen — one row is enough
- Systemically unwell, hypoxaemia, marked tachypnoea, hypotension, rapid worsening, poor oral intake or significant frailty → Same-day hospital via the sepsis pathway
- PE: pleuritic pain, breathlessness or haemoptysis, especially with risk factors → Wells. Likely → Same-day CTPA, do not wait for D-dimer; unlikely → D-dimer.
- Unexplained haemoptysis aged ≥40 → Suspected cancer pathway. No duration or smoking requirement; do not delay for a CXR.
- Aged 40+, ≥2 unexplained of cough, fatigue, breathlessness, chest pain, weight or appetite loss (≥1 if ever smoked) → Urgent CXR (NG12)
- Infant with poor feeding or other respiratory distress → Same-day paediatrics. Suspected pertussis is notifiable.
- Suspected active TB (weight loss, night sweats) → CXR, Urgent TB service, notify UKHSA
3Assess — only once blocks 0–2 are answered
☐ RR, HR, BP, temperature, SpO₂ if breathless, chest pain, fever, suspected LRTI, comorbidity, frailty or concern ☐ Crackles, wheeze, absent breath sounds, dullness, work of breathing, JVP and oedema ☐ CXR for focal signs where it changes management, haemoptysis, persistent infection or suspected cancer
Viral illness: no routine tests. Point-of-care CRP only if pneumonia is uncertain (locally validated). Sputum colour does not decide antibiotics.
4Classify — only if the screen is negative
- Viral URTI — coryza, sore throat, mild fever; settles in 7–14 days → self-care.
- Acute bronchitis — viral in >90%, no pneumonia; lasts about 3 weeks → no antibiotic.
- Pneumonia — productive cough, fever, focal chest signs; no CXR needed to diagnose → CRB-65.
- Influenza — sudden fever and myalgia. Pertussis — paroxysms ± whoop or vomiting → notify UKHSA.
- COPD exacerbation — sustained worsening of breathlessness, cough or sputum from baseline.
- Uncertain, or 3–8 weeks (post-viral, pertussis, resolving pneumonia) — say so and reassess; >8 weeks → chronic cough algorithm.
5Treat today — doses: NICE/SPC, BNF, local formulary
- Viral or bronchitis: self-care, honey (not under 1 year), paracetamol; no routine codeine. Back-up antibiotic only if higher risk, to use if worse rapidly or significantly.
- Antibiotic genuinely indicated (NG120): doxycycline 200 mg day 1, then 100 mg daily for 4 days (not in pregnancy); alternatives amoxicillin, clarithromycin, erythromycin.
- Low-severity pneumonia: amoxicillin 500 mg TDS for 5 days; penicillin allergy → doxycycline (5 days). Atypical suspected in moderate severity → add clarithromycin 500 mg BD.
- Influenza, at-risk group: oseltamivir 75 mg BD for 5 days within 48 h, without waiting for a test. COPD exacerbation: prednisolone 30 mg daily for 5 days; antibiotic by sputum purulence, not CRP.
6Refer routinely
- No routine follow-up CXR after pneumonia; consider it for persisting signs, incomplete recovery, recurrence or cancer concern.
- Post-COVID symptoms >12 weeks → long COVID assessment and clinic (NG188).
- Smokers → NHS Stop Smoking Service. Flu and pneumococcal vaccination per the Green Book.
7Never reassure by
- A normal SpO₂: it does not exclude PE, pneumonia, asthma or ACS.
- A low CRB-65 when you are still worried; the score leaves out oxygenation.
- No whoop: adults and young infants often have none.
- Short duration or no smoking history in haemoptysis at 40+.
- A normal CXR when suspicion of cancer persists.
- A back-up antibiotic in place of a same-day review for red flags.
8Safety-net — say it, then document it
999 “Call 999 if you are struggling to breathe, have chest pain or become confused. For your child: pauses in breathing, blue lips, a noisy breath in at rest, or working very hard to breathe.”
Same day “The cough can take 3 to 4 weeks to clear. Contact us the same day if you get rapidly or significantly worse, more breathless, cough up blood, can't keep fluids down, or are no better 48 hours into antibiotics.”
✓Safe to leave primary care only if — all five, documented
No block 0–2 row applies
Observations recorded where indicated; CRB-65 if pneumonia
One cause named, or uncertainty stated
Antibiotic decision per NG120/NG250; review set by risk
Safety-net given, with the 3–4 week course
Summary of the full Reasoning GP acute cough algorithm, which holds the detail, examination, atypical pneumonia, COVID-19 and evidence. Sources: NICE NG120, NG250, NG237, NG158, NG12 (updated April 2026), NG115, TA168, NG33, NG188; UKHSA pertussis and influenza guidance; Green Book. Clinical reference — follow local pathways and check doses: NICE/SPC, BNF.