Acute bronchitis is typically associated with a cough that is worse at night or with exercise; lasts >2 weeks in half of patients and 4 weeks in a quarter of patients; may be associated with bronchospasm and/or excessive mucus production.
Diagnosis is primarily clinical. Other causes for acute cough such as pneumonia, asthma, or postnasal drip should be ruled out if suspected.
Treatment is aimed at symptom reduction until infection is resolved and bronchial damage repaired. Antibiotics are not recommended in the majority of patients.
Complications are rare; the primary complication is a postbronchitis syndrome, which can produce a cough lasting several months.
Acute bronchitis is defined as a self-limiting lower respiratory tract infection, to distinguish this condition from common colds and other upper respiratory ailments. Bronchitis refers specifically to infections causing inflammation in the bronchial airways, whereas pneumonia denotes infection in the lung parenchyma resulting in consolidation of the affected segment or lobe.
Although there is no universally accepted definition for acute bronchitis, the criteria proposed by MacFarlane offer a practical approach: (a) an acute illness of <21 days; (b) cough as the predominant symptom; (c) at least 1 other lower respiratory tract symptom, such as sputum production, wheezing, chest pain; (d) no alternative explanation for the symptoms. While the MacFarlane criteria state that the symptoms usually last for <3 weeks, other studies have shown that cough may linger for >30 days in about a quarter of patients with acute bronchitis. Consequently, acute bronchitis can still be present in patients with coughs lasting for >1 month.
This topic focuses on acute bronchitis in adults.
History and exam
Key diagnostic factors
- presence of risk factors
- duration of cough <30 days
- productive cough
- no history of chronic respiratory illness
- exclusion of other respiratory and cardiac illness as cause for symptoms
Other diagnostic factors
- viral or atypical bacterial infection exposure
- cigarette smoking
- household pollution exposure
1st investigations to order
- clinical diagnosis
Investigations to consider
- pulmonary function test
- chest x-ray
- C-reactive protein
cough ≤4 weeks
cough >4 weeks
- Coronavirus disease 2019 (COVID-19)
- Allergic rhinitis
- Acute cough due to acute bronchitis in immunocompetent adult outpatients: CHEST expert panel report
- Cough (acute): antimicrobial prescribing
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