Editing Cough (section)

==Differential diagnosis==
A cough in children may be either a normal physiological reflex or due to an underlying cause.<ref name=Review10/> In healthy children it may be normal in the absence of any disease to cough ten times a day.<ref name=Review10/> The most common cause of an acute or subacute cough is a viral [[respiratory tract infection]].<ref name=Review10/> A healthy adult also coughs 18.6 times a day on average, but in the population with respiratory disease the geometric mean frequency is 275 times a day.<ref>{{cite journal |first1=Yousaf |last1=Nadia |first2=William |last2=Monteiro |first3=Sergio |last3=Matos |first4=Surinder S. |last4=Birring |first5=Ian D. |last5=Pavord |title=Cough frequency in health and disease |url=https://erj.ersjournals.com/content/41/1/241 |journal=European Respiratory Journal |date=2013 |volume=41|issue=1 | pages=241–243 |doi=10.1183/09031936.00089312|pmid=23277523 |doi-access=free }}</ref> In adults with a chronic cough, i.e. a cough longer than 8 weeks, more than 90% of cases are due to [[post-nasal drip]], [[asthma]], [[eosinophilic bronchitis]], and [[gastroesophageal reflux disease]].<ref name=Review10/> The causes of chronic cough are similar in children with the addition of [[bronchitis|bacterial bronchitis]].<ref name=Review10/>

===Infections===
A cough can be the result of a [[respiratory tract infections|respiratory tract infection]] such as the [[common cold]], [[COVID-19]], [[acute bronchitis]], [[pneumonia]], [[pertussis]], or [[tuberculosis]]. In the vast majority of cases, acute coughs, i.e. coughs shorter than 3 weeks, are due to the common cold.<ref name="pmid20015366">{{cite journal |vauthors=Dicpinigaitis PV, Colice GL, Goolsby MJ, Rogg GI, Spector SL, Winther B |title=Acute cough: a diagnostic and therapeutic challenge |journal=Cough |volume=5 |pages=11 |year=2009 |pmid=20015366 |pmc=2802352 |doi=10.1186/1745-9974-5-11 |quote= In the vast majority of cases, acute cough is due to acute viral upper respiratory tract infection (URTI), i.e., the common cold. |doi-access=free }}</ref> In people with a normal chest X-ray, tuberculosis is a rare finding. Pertussis is increasingly being recognised as a cause of troublesome coughing in adults.

After a respiratory tract infection has cleared, the person may be left with a [[post-viral cough|postinfectious cough]]. This typically is a dry, non-productive cough that produces no [[phlegm]]. Symptoms may include a tightness in the chest, and a tickle in the throat. This cough may often persist for weeks after an illness. The cause of the cough may be inflammation similar to that observed in repetitive stress disorders such as [[carpal tunnel syndrome]]. The repetition of coughing produces inflammation which produces discomfort, which in turn produces more coughing.<ref name="pmid16428703">{{cite journal | vauthors = Braman SS | title = Postinfectious cough: ACCP evidence-based clinical practice guidelines | journal = Chest | volume = 129 | issue = 1 Suppl | pages = 138S–146S | date = January 2006 | pmid = 16428703 | doi = 10.1378/chest.129.1_suppl.138S | doi-access = free }}</ref> Postinfectious cough typically does not respond to conventional cough treatments. Medication used for postinfectious coughs may include [[ipratropium]]<ref name="pmid16428703"/> to treat the inflammation, as well as cough suppressants to reduce frequency of the cough until inflammation clears.<ref>{{Cite web |title=Cystic fibrosis - Diagnosis and treatment - Mayo Clinic |url=https://www.mayoclinic.org/diseases-conditions/cystic-fibrosis/diagnosis-treatment/drc-20353706 |access-date=2022-05-24 |website=www.mayoclinic.org |language=en}}</ref> Inflammation may increase sensitivity to other existing issues such as [[allergies]], and treatment of other causes of coughs (such as use of an air purifier or allergy medicines) may help speed recovery.<ref>{{Cite web |title=UpToDate |url=https://www.uptodate.com/contents/nonallergic-rhinitis-runny-or-stuffy-nose-beyond-the-basics |access-date=2022-05-24 |website=www.uptodate.com}}</ref>

===Reactive airway disease===
When coughing is the only complaint of a person who meets the criteria for asthma ([[bronchial hyperresponsiveness]] and reversibility), this is termed [[cough-variant asthma]]. Atopic cough and [[eosinophilic bronchitis]] are related conditions. Atopic cough occurs in individuals with a [[family history]] of [[atopy]] (an allergic condition), abundant [[eosinophils]] in the sputum, but with normal airway function and responsiveness. Eosinophilic bronchitis is characterized by [[eosinophils]] in sputum and in [[bronchoalveolar lavage]] fluid without airway hyperresponsiveness or an atopic background.<ref>{{cite journal |last1=Niimi |first1=A |title=Cough and Asthma |journal=Current Respiratory Medicine Reviews |date=February 2011 |volume=7 |issue=1 |pages=47–54 |doi=10.2174/157339811794109327 |pmid=22081767 |pmc=3182093}}</ref> This condition responds to treatment with [[corticosteroids]]. Cough can also worsen in an [[acute exacerbation of chronic obstructive pulmonary disease]].

Asthma is a common cause of chronic cough in adults and children. Coughing may be the only symptom the person has from their asthma, or asthma symptoms may also include wheezing, shortness of breath, and a tight feeling in their chest. Depending on how severe the asthma is, it can be treated with bronchodilators (medicine which causes the airways to open up) or inhaled steroids. Treatment of the asthma should make the cough go away.

[[Bronchitis#Chronic bronchitis|Chronic bronchitis]] is defined clinically as a persistent cough that produces sputum (phlegm) and mucus, for at least three months in two consecutive years. Chronic bronchitis is often the cause of "[[smoker's cough]]". The tobacco smoke causes inflammation, secretion of mucus into the airway, and difficulty clearing that mucus out of the airways. Coughing helps clear those secretions out. May be treated by quitting smoking. May also be caused by [[pneumoconiosis]] and long-term fume inhalation.

===Gastroesophageal reflux===
In people with unexplained cough, [[gastroesophageal reflux disease]] should be considered.<ref name=Review10/> This occurs when acidic contents of the stomach come back up into the esophagus. Symptoms usually associated with [[GERD]] include heartburn, sour taste in the mouth, or a feeling of acid reflux in the chest, although, more than half of the people with cough from GERD do not have any other symptoms. An esophageal pH monitor can confirm the diagnosis of GERD. Sometimes GERD can complicate respiratory ailments related to cough, such as asthma or bronchitis. The treatment involves anti-acid medications and lifestyle changes with surgery indicated in cases not manageable with conservative measures.

===Air pollution===
Coughing may be caused by [[air pollution]] including [[tobacco smoke]], particulate matter, irritant gases, and dampness in a home.<ref name=Review10/>
The human health effects of poor air quality are far reaching, but principally affect the body's respiratory system and the cardiovascular system. Individual reactions to air pollutants depend on the type of pollutant a person is exposed to, the degree of exposure, the individual's health status and genetics. People who exercise outdoors on hot, smoggy days, for example, increase their exposure to pollutants in the air.

===Foreign body===
A [[foreign body]] can sometimes be suspected, for example if the cough started suddenly when the patient was eating. Rarely, sutures left behind inside the airway branches can cause coughing. A cough can be triggered by dryness from [[mouth breathing]] or recurrent aspiration of food into the [[Vertebrate trachea|windpipe]] in people with [[dysphagia|swallowing difficulties]].<ref>{{Cite web |title=Cough |url=https://www.mayoclinic.org/symptoms/cough/basics/definition/sym-20050846 |access-date=2022-03-27 |website=Mayo Clinic |language=en}}</ref><ref>{{Cite web |title=Why You Cough |url=https://www.webmd.com/cold-and-flu/overview |access-date=2022-03-27 |website=WebMD |language=en}}</ref>

===Drug-induced cough===
Drugs used for treatments other than coughs, such as [[ACE inhibitor]]s which are often used to treat [[Hypertension|high blood pressure]], can sometimes cause cough as a side effect, and stopping their use will stop the cough.<ref name="pmid16428706">{{cite journal | vauthors = Dicpinigaitis PV | title = Angiotensin-converting enzyme inhibitor-induced cough: ACCP evidence-based clinical practice guidelines | journal = Chest | volume = 129 | issue = 1 Suppl | pages = 169S–173S | date = January 2006 | pmid = 16428706 | doi = 10.1378/chest.129.1_suppl.169S }}</ref> Beta blockers similarly cause cough as an adverse event.<ref name=":2" />

===Habit cough===
A [[Habit cough|habit cough]] is one that responds to behavioral or psychiatric therapy after organic causes have been excluded. Absence of the cough during sleep is common, but not diagnostic. A tic cough is thought to be more common in children than in adults.<ref name="pmid16428707">{{cite journal |vauthors=Irwin RS, Glomb WB, Chang AB |title=Habit cough, tic cough, and psychogenic cough in adult and pediatric populations: ACCP evidence-based clinical practice guidelines |journal=Chest |volume=129 |issue=1 Suppl |pages=174S–179S |date=January 2006 |pmid=16428707 |doi=10.1378/chest.129.1_suppl.174S |doi-access=free }}</ref>
{{Clarify | text = A similar disorder is the [[Tic cough|somatic cough syndrome]] previously called the ''psychogenic cough''.| date = November 2024 | reason = They linked article shows that these terms are used to called the same condition.}}

===Neurogenic cough===
Some cases of chronic cough may be attributed to a sensory neuropathic disorder.<ref name="pmid21524236">{{cite journal |vauthors=Gibson PG, Ryan NM |title=Cough pharmacotherapy: current and future status |journal=Expert Opinion on Pharmacotherapy |volume=12 |issue=11 |pages=1745–1755 |date=August 2011 |pmid=21524236 |doi=10.1517/14656566.2011.576249 |s2cid=24560981 }}</ref> Treatment for neurogenic cough may include the use of certain neuralgia medications. Coughing may occur in [[tic disorder]]s such as [[Tourette syndrome]], although it should be distinguished from throat-clearing in this disorder.

===Other===
Cough may also be caused by conditions affecting the lung tissue such as [[bronchiectasis]], [[cystic fibrosis]], [[interstitial lung disease]]s and [[sarcoidosis]]. Coughing can also be triggered by [[benign]] or [[lung cancer|malignant lung tumor]]s or mediastinal masses. Through irritation of the nerve, diseases of the external auditory canal (wax, for example) can also cause cough. Cardiovascular diseases associated with cough are heart failure, pulmonary infarction and aortic aneurysm. Nocturnal cough is associated with heart failure, as the [[left ventricle]] doesn't effectively pump blood forward, resulting in blood being backed up in the [[pulmonary veins]], which in turn causing [[pulmonary edema]] and resultant cough.<ref name="Farzan">{{Citation |last=Farzan |first=Sattar |title=Cough and Sputum Production |date=1990 |work=Clinical Methods: The History, Physical, and Laboratory Examinations |editor-last=Walker |editor-first=H. Kenneth |url=https://www.ncbi.nlm.nih.gov/books/NBK359/ |access-date=2025-04-10 |edition=3rd |place=Boston |publisher=Butterworths |isbn=978-0-409-90077-4 |pmid=21250200 |editor2-last=Hall |editor2-first=W. Dallas |editor3-last=Hurst |editor3-first=J. Willis}}</ref> Other causes of nocturnal cough include [[asthma]], [[post-nasal drip]] and [[gastroesophageal reflux disease]] (GERD).<ref>{{cite web |url=http://www.nlhep.org/books/pul_Pre/chronic-cough.html |title=C.Chronic Cough |access-date=2010-10-10 |url-status=dead |archive-url=https://web.archive.org/web/20101001113940/http://www.nlhep.org/books/pul_Pre/chronic-cough.html |archive-date=2010-10-01 }} National Lung Health Education Program > C. Chronic Cough] The Snowdrift Pulmonary Foundation, Inc. 2000. {{ISBN|0-9671809-2-9}}</ref> Another cause of cough occurring preferentially in [[supine position]] is recurrent aspiration.<ref name=Farzan/> Cough can also be a symptom of [[mast cell activation syndrome|mast cell activation syndrome (MCAS)]].<ref name=""PMID27012973"">{{cite journal |vauthors=Afrin LB, Butterfield JH, Raithel M, Molderings GJ |title=Often seen, rarely recognized: mast cell activation disease--a guide to diagnosis and therapeutic options |journal=The American Journal of the Medical Science |volume=48 |issue=3 |date=2016 |pages=190–201 |doi=10.3109/07853890.2016.1161231 |pmid=27012973 |url=|doi-access=free}}</ref>

Given its irritant nature to mammal tissues, [[capsaicin]] is widely used to determine the cough threshold and as a tussive stimulant in clinical research of cough suppressants. Capsaicin is what makes [[chili pepper]]s spicy, and might explain why workers in factories with these fruits can develop a cough.

Coughing may also be used for social reasons, and as such is not always involuntary. A voluntary cough, often written as "ahem", can be used to attract attention or express displeasure, as a form of [[nonverbal]], [[paralingual]] [[metacommunication]].<ref>{{Cite web|url=http://onomatopoeialist.com/ahem/|title=ahem|date=August 10, 2013|website=Onomatopoeia List|access-date=April 11, 2022|archive-date=April 4, 2023|archive-url=https://web.archive.org/web/20230404065206/http://onomatopoeialist.com/ahem/|url-status=dead}}</ref><ref>{{cite book |last1=Nänny |first1=Max |last2=Fischer |first2=Olga |title=Form Miming Meaning: Iconicity in Language and Literature |date=1999 |publisher=John Benjamins Publishing |isbn=9789027221797 |url=https://books.google.com/books?id=fLrIl-uPoQ8C&q=onomatopoeia+words+ahem+hem&pg=PA137 |access-date=25 July 2019 |language=en}}</ref>

===Airway clearance===
{{Further|Airway clearance therapy}}
Coughing, and [[Airway clearance therapy|huffing]] are important ways of removing mucus as [[sputum]] in many conditions such as [[cystic fibrosis]], and [[Bronchitis#Chronic bronchitis|chronic bronchitis]].