Trusted medical expertise in seconds.

Access 1,000+ clinical and preclinical articles. Find answers fast with the high-powered search feature and clinical tools.

Try free for 5 days
Evidence-based content, created and peer-reviewed by physicians. Read the disclaimer.


Last updated: March 29, 2021

Summarytoggle arrow icon

A cough is a forceful expulsion of air from the lungs that helps to clear secretions, foreign bodies, and irritants from the airway. It may be classified as acute (< 3 weeks), subacute (3–8 weeks), or chronic (> 8 weeks), as well as productive (with sputum/mucus expectoration) or dry. Upper respiratory tract infections (URI) and acute bronchitis are the most common causes of acute cough. Subacute cough is often a sequela of a URI (postinfectious cough) but can also be due to chronic bronchitis or pneumonia. Chronic cough is often caused by rhinitis/sinusitis (upper airway cough syndrome), asthma, GERD, and ACE inhibitors. A thorough medical history and physical examination often suffice to diagnose the etiology of cough. Chronic cough or the presence of associated red flag symptoms (dyspnea, fever, hemoptysis, weight loss) are indications for further investigation. Sputum culture, chest x-ray/CT scan, and pulmonary function tests are useful diagnostic tests in the evaluation of cough, but are not routinely indicated. Treatment of cough depends on the underlying etiology.

  • Definition: a forceful expulsion of air from the lungs that helps to clear secretions, foreign bodies, and irritants from the airway
  • Triggers: cough may be voluntary or a reflex to airway irritants/triggers
  • Cough reflex arc
    • Irritation of cough receptors in the nose, sinuses, upper and lower respiratory tract (see the triggers above)
    • Transmission along the afferent pathway via the internal laryngeal nerve of the vagus nerve (CN X) to the cough center in the medulla
    • Generation of efferent signal in the medulla and initiation of cough via the vagus, phrenic, and spinal motor nerves
  • Mechanism of cough reflex: initiation of the cough reflex arc leads to
    • Rapid inspiration, closure of the epiglottis and vocal cords (which traps inhaled air in the lungs), and contraction of the diaphragm, expiratory, and abdominal muscles → rapid increase of intrathoracic pressure
    • A sudden opening of the vocal cords and forceful expulsion of air from the lungs



Clinical examination


Acute cough

Subacute cough

Chronic cough

Symptomatic treatment of a cough

Antitussive medications decrease coughing, which is important for the expectoration of mucus! They are not usually indicated if an infection is the cause of cough.



  • An acute cough is often a clinical diagnosis (diagnostic tests are not routinely indicated in this case).
  • Patients with chronic cough and/or red flag symptoms (see “Approach” above) require further assessment.

Laboratory tests


Pulmonary function tests


Close history taking and physical examination are sufficient to diagnose the cause of an acute cough without red flag symptoms! In chronic cough and cough with red flag symptoms, thoracic x-ray and pulmonary function testing should be considered at an early stage.References:[11][20][21][22]


Differential diagnosis of acute cough (< 3 weeks)

Non-life-threatening causes
Life-threatening causes
In children

Subacute cough (3–8 weeks)

Differential diagnosis of chronic cough

In adults

(> 8 weeks)

In children

(> 4 weeks)


  1. Walker HK, Hall WD, Hurst WJ, Silverman ME, Morrison G. Clinical Methods: The History, Physical, and Laboratory Examinations. Butterworths ; 1990
  2. Benich JJ, Carek PJ. Evaluation of the patient with chronic cough. Am Fam Physician. 2011; 84 (8): p.887-892.
  3. Kryger MH, Roth T, Dement WC. Principles and Practice of Sleep Medicine. Elsevier ; 2010
  4. Cough in Adults. Updated: July 1, 2016. Accessed: May 22, 2017.
  5. Coughlin L. Cough: diagnosis and management. Am Fam Physician. 2007; 75 (4): p.567-575.
  6. Pratter MR. Chronic upper airway cough syndrome secondary to rhinosinus diseases (previously referred to as postnasal drip syndrome): ACCP evidence-based clinical practice guidelines. Chest. 2006; 129 (1 Suppl): p.63S-71S. doi: 10.1378/chest.129.1_suppl.63S . | Open in Read by QxMD
  7. Gorguner M, Akgun M. Acute inhalation injury. Eurasian J Med. 2010; 42 (1): p.28-35. doi: 10.5152/eajm.2010.09 . | Open in Read by QxMD
  8. Braman SS. Postinfectious cough: ACCP evidence-based clinical practice guidelines. Chest. 2006; 129 (1 Suppl): p.138S-146S. doi: 10.1378/chest.129.1_suppl.138S . | Open in Read by QxMD
  9. Tatar M, Hanacek J, Widdicombe J. The expiration reflex from the trachea and bronchi. Eur Respir J. 2008; 31 (2): p.385-390. doi: 10.1183/09031936.00063507 . | Open in Read by QxMD
  10. Spina D, Page CP, Metzger WJ, O'Connor BJ. Drugs for the Treatment of Respiratory Diseases. Cambridge University Press ; 2003
  11. Ternesten-Hasséus E, Larsson S, Millqvist E. Symptoms induced by environmental irritants and health-related quality of life in patients with chronic cough - A cross-sectional study. Cough. 2011; 7 : p.6. doi: 10.1186/1745-9974-7-6 . | Open in Read by QxMD
  12. Belvisi MG, Geppetti P. Cough. 7: Current and future drugs for the treatment of chronic cough. Thorax. 2004; 59 (5): p.438-440.
  13. Guyton AC. Textbook of Medical Physiology. Elsevier ; 2006
  14. George L, Brightling CE. Eosinophilic airway inflammation: role in asthma and chronic obstructive pulmonary disease. Ther Adv Chronic Dis. 2016; 7 (1): p.34-51. doi: 10.1177/2040622315609251 . | Open in Read by QxMD
  15. Priftis KN, Anthracopoulos MB, Eber E, Koumbourlis AC, Wood RE. Paediatric bronchoscopy. Prog Respir Res. 2010; 38 : p.30-41. doi: 10.1159/000314382 . | Open in Read by QxMD
  16. Bronchoalveolar Lavage. Updated: May 1, 2004. Accessed: May 22, 2017.
  17. Cohen HA, Rozen J, Kristal H, et al. Effect of honey on nocturnal cough and sleep quality: a double-blind, randomized, placebo-controlled study.. Pediatrics. 2012; 130 (3): p.465-71. doi: 10.1542/peds.2011-3075 . | Open in Read by QxMD
  18. Paul IM, Beiler J, McMonagle A, Shaffer ML, Duda L, Berlin CM Jr. Effect of honey, dextromethorphan, and no treatment on nocturnal cough and sleep quality for coughing children and their parents.. Arch Pediatr Adolesc Med. 2007; 161 (12): p.1140-6. doi: 10.1001/archpedi.161.12.1140 . | Open in Read by QxMD
  19. Oduwole O, Udoh EE, Oyo-Ita A, Meremikwu MM. Honey for acute cough in children. Cochrane Database Syst Rev. 2018 . doi: 10.1002/14651858.cd007094.pub5 . | Open in Read by QxMD
  20. Smith MP, Lown M, Singh S, et al. Acute Cough Due to Acute Bronchitis in Immunocompetent Adult Outpatients: CHEST Expert Panel Report.. Chest. 2020; 157 (5): p.1256-1265. doi: 10.1016/j.chest.2020.01.044 . | Open in Read by QxMD
  21. Kinkade S, Long NA. Acute Bronchitis.. Am Fam Physician. 2016; 94 (7): p.560-565.
  22. Becker LA, Hom J, Villasis-Keever M, van der Wouden JC. Beta2-agonists for acute cough or a clinical diagnosis of acute bronchitis.. Cochrane Database Syst Rev. 2015 : p.CD001726. doi: 10.1002/14651858.CD001726.pub5 . | Open in Read by QxMD
  23. Irwin RS. Guidelines for treating adults with acute cough. Am Fam Physician. 2007; 75 (4): p.476-482.
  24. Cox N, Hinkle R. Infant botulism. Am Fam Physician. 2002; 65 (7): p.1388-1392.
  25. Townley RG, Suliaman F. The mechanism of corticosteroids in treating asthma. Ann Allergy. 1987; 58 (1): p.1-6.
  26. Sylvester DC, Karkos PD, Vaughan C, et al. Chronic cough, reflux, postnasal drip syndrome, and the otolaryngologist. Int J Otolaryngol. 2012 . doi: 10.1155/2012/564852 . | Open in Read by QxMD
  27. Vaezi MF. Atypical manifestations of gastroesophageal reflux disease. MedGenMed. 2005; 7 (4): p.25.
  28. Badillo R, Francis D. Diagnosis and treatment of gastroesophageal reflux disease. World J Gastrointest Pharmacol Ther. 2014; 5 (3): p.105-112. doi: 10.4292/wjgpt.v5.i3.105 . | Open in Read by QxMD
  29. Chest Physiotherapy. Updated: March 1, 2017. Accessed: May 22, 2017.
  30. Padma L. Current drugs for the treatment of dry cough. J Assoc Physicians India. 2013; 61 (5 Suppl): p.9-13.
  31. Herold G. Internal Medicine. Herold G ; 2014