Acute bronchitis

Overview

Acute bronchitis is an acute inflammatory condition of the bronchi/bronchioles, almost always viral and self-limiting. The key clinical skill is knowing when NOT to prescribe antibiotics.

Presentation

•Cough - cardinal symptom; initially dry, may become productive (clear/yellow-green sputum)

•Wheeze - bronchospasm from airway inflammation

•Mild malaise, low-grade fever, chest tightness

•Examination - scattered rhonchi; crackles that clear with coughing (unlike pneumonia)

⚠️

Crackles that PERSIST after coughing, focal chest signs (bronchial breathing, dull percussion), or significant systemic upset - think pneumonia, not bronchitis.

Investigations

Acute bronchitis is a clinical diagnosis - investigations are not routinely required in a well patient.

•CRP (point-of-care) - most useful investigation; guides antibiotic prescribing decision

•Chest X-ray - only if pneumonia suspected (focal signs, significant systemic upset, failure to improve)

•Pulse oximetry - if breathlessness is prominent

Management

🥇 First-line

•reassurance and self-care - viral illness, antibiotics unlikely to help, resolves within 3 weeks in most cases

•Symptomatic measures - hydration, rest, paracetamol/ibuprofen, honey for cough

•Smoking cessation advice where applicable

CRP	Action
< 20 mg/L	No antibiotics
20-100 mg/L	Delayed prescription - use if not improving after 3-5 days
> 100 mg/L	Immediate antibiotic prescription

•Antibiotic of choice: doxycycline (NICE 2022)

•Immediate antibiotics also indicated if: age >65 with comorbidities, significantly unwell, or higher risk of complications

🎯

Doxycycline is the preferred antibiotic per NICE 2022 for acute bronchitis - used as a delayed or immediate prescription depending on CRP threshold.

Complications

•Progression to community-acquired pneumonia - key complication; more likely in elderly, significant comorbidities, or immunocompromised

•Exacerbation of underlying lung disease - asthma, COPD, or bronchiectasis

•Post-infective cough - persistent dry cough weeks beyond acute illness

Safety-netting and follow-up

•Routine follow-up not necessary - safety-netting is the priority

•Return if: symptoms worsen rapidly, fail to improve within expected timeframe, or new focal signs develop

•Warn patients: residual dry cough can persist for up to 3 weeks (post-infective airway hyper-reactivity)