{
  "id": "cough",
  "title": "Cough",
  "lang": "en",
  "source_lang": "en",
  "summary": "A cough is a forceful expulsion of air from the lungs, produced by a reflex that protects the airways, and it is among the most common reasons for seeking medical care.",
  "category": "health",
  "subcategory": "diseases",
  "type": "concept",
  "aliases": [
    "coughing",
    "tussis"
  ],
  "generated_at": "2026-10-09",
  "model": "pro/claude-haiku-5-5",
  "url": "https://aiwiki.page/en/cough/",
  "translations": {
    "zh-Hans": {
      "url": "https://aiwiki.page/zh/cough/",
      "json": "https://aiwiki.page/zh/cough.json"
    }
  },
  "sections": [
    {
      "heading": "",
      "text": "Cough is a forceful expulsion of air from the lungs, produced by a cough reflex that protects the airways from secretions, irritants and foreign material. It is one of the most frequent reasons people seek medical care. Occasional coughing is normal, but a cough that persists can be a symptom of a range of conditions, from mild infections to serious lung and heart disease."
    },
    {
      "heading": "Physiology",
      "text": "The cough reflex is usually described as a reflex arc with three parts. The afferent limb is made up of receptors and sensory nerves, the central component lies in the brainstem, and the efferent limb consists of motor nerves that drive the muscles of coughing. It is a well-integrated reflex, which has afferent limb consisting of receptors and afferent nerves, the central cough center in the brainstem and the efferent limb consisting of motor nerves supplying the muscles of coughing. Sensory receptors are concentrated in the upper airways, and the cough reflex is triggered by stimulation of mechano-receptors in the larynx, trachea, main carina and central airways. The afferent sensory signals are transmitted via pharyngeal branches of the glossopharyngeal nerve and by sensory fibers of the vagus nerve to the medulla oblongata.\n\nTwo classes of receptors are particularly important. The cough reflex is initiated by activation of bronchopulmonary C fibers and the mechanically-sensitive cough receptors. Stimuli initiating cough through activation of one or both of these vagal afferent nerves include capsaicin, acid, bradykinin, cinnamaldehyde, cigarette smoke, and non-isotonic aerosols.\n\nA single cough is typically divided into three phases: inspiratory, compressive and expiratory. Air is first drawn in; the glottis then closes while the expiratory muscles contract, building pressure in the chest; finally the glottis opens and air leaves the lungs in a rapid burst. The pressure in this phase can be large, with intrapleural pressure reaching about 100 cm H₂O in the standard description of the mechanism. Each burst is terminated by one of the following three mechanisms: (a) re-closure of the glottis, (b) termination of the expiratory muscles activity, or (c) exhaustion of the available gas flow reserve in the lung.\n\nThe reflex serves a protective function. The important function of the cough reflex is to maintain the airways and alveoli clear and healthy. Coughing can also spread respiratory infections to others, which is one reason coughing has public-health significance."
    },
    {
      "heading": "Classification by duration",
      "text": "Clinical classification is based mainly on how long a cough lasts. Acute cough is distinguished as lasting up to 8 weeks, and chronic cough as lasting more than eight weeks. In addition, cough that lasts for three to eight weeks is classified as subacute cough by some authors. Pediatric thresholds differ: the Australian and American College Chest Physicians (CACP) guidelines on cough in children defined chronic cough as a cough that lasts longer than 4 weeks, whereas the British Thoracic Society used 8 weeks and introduced an intermediate category of \"prolonged acute cough\" for children.\n\nSome coughs are self-perpetuating. Once started, each spasm can irritate the airway lining enough to trigger the next, so the cough can continue even without mucus or foreign bodies, a pattern described as a dry cough. There are, however, many cases where persistent cough is self-perpetuating, so that each cough spell applies such forces to the airway mucosa that stimulates and triggers a subsequent paroxysm, even in the absence of secretions or foreign bodies in the airways."
    },
    {
      "heading": "Causes",
      "text": "Acute cough is most often linked to viral respiratory infection. Viral infection releases inflammatory mediators that disturb the airway lining and make cough receptors more sensitive, which may explain why coughing often outlasts other cold symptoms. Cough usually emerges later than other symptoms and can become the most bothersome complaint in the second week. From day 4 cough becomes the most bothersome and by far the longest lasting symptom until day 14. Most acute coughs resolve on their own, and the trajectory of symptoms is a key reason why many acute infections are self-limited.\n\nChronic cough is far more heterogeneous. Chronic cough is estimated to affect roughly 10% of adults, and it is a common reason for outpatient consultation. Key differential diagnoses include chronic obstructive pulmonary disease (COPD) in smokers, bronchial asthma, drug-related cough, and empirically treated conditions such as upper airway cough syndrome (UACS), cough variant asthma, eosinophilic bronchitis, and gastroesophageal reflux disease (GERD), while diseases such as tuberculosis and interstitial lung diseases are among the rare causes. Common causes such as allergies and reflux are often linked to postnasal drip, which drives the upper airway cough syndrome described above. Serious but less common causes include lung cancer and heart problems.\n\nIn many people with chronic cough, no single cause is found. Although cough is a common symptom of many lung diseases, chronic cough can't always be linked to another disease or condition and it often doesn't respond to treatment. Research into this group has focused on the neuro-immune interaction that governs cough sensitivity. A dysregulation of either or both of the airway immune or nervous system could lead to an altered (frequently increased) cough reflex sensitivity and increased coughing.\n\nIn children, the differential diagnosis differs. An isolated cough in an otherwise healthy child may be secondary to recurrent viral bronchiolitis, post-infectious etiology, pertussis, cough variant asthma, post-nasal drip, or may be psychogenic in origin."
    },
    {
      "heading": "Diagnosis",
      "text": "Evaluation of cough rests mainly on history and physical examination. The history and physical examination are the basis of diagnostic evaluation. For acute bronchitis without complications, guidelines advise against routine tests. When the clinical diagnosis is that of an acute, uncomplicated bronchitis, no laboratory tests, sputum evaluation, or chest x-rays should be performed, and antibiotics should not be given.\n\nSome features call for prompt investigation. Foreign body aspiration is a notable example: if unnoticed, foreign body aspiration may cause prolonged cough and occasionally recurrent pneumonia, especially in children and the elderly. Chronic cough evaluation is often resource-intensive, and guidance from the German guideline is that the German Clinical Practice Guideline on Acute and Chronic Cough was updated in 2021 and contains a description of the recommended stepwise, patient-centered, and evidence-based procedure for the management of chronic cough."
    },
    {
      "heading": "Treatment",
      "text": "Management is generally organised around the cause. Treatments depend on the underlying cause. But they usually involve taking medicines and making changes to your routine.\n\nAcute cough. Self-care options include honey, herbal products and over-the-counter medicines. Self-care treatments available for acute cough include honey, herbal medicines and over-the-counter cough medicines (for example, expectorants and cough suppressants [also called antitussives]). The evidence base for these options is weak. There is inadequate evidence for the efficacy of antitussive or expectorant drugs against acute cough. In one comparison, honey did not reduce the frequency and severity of cough at 1 day follow-up compared with an antitussive (dextromethorphan; very low quality evidence).\n\nGuidance differs by cause. For cough with the common cold, a 2006 review of evidence found no evidence to support or refute the use of OTC antitussive agents, expectorants, mucolytic agents, antihistamines, or combination products for reducing cough. By contrast, in acute bronchitis, antitussive agents were found to be \"occasionally useful\" and are recommended for short-term symptomatic relief of coughing. Chinese guidelines recommend a combination of first-generation antihistamines and an antitussive agent for cough due to the common cold, which shows how regional practice can diverge from other recommendations.\n\nCentral-acting antitussives such as codeine and dextromethorphan have been a particular focus of debate. The 2006 American College of Chest Physicians guidelines ranked peripherally acting drugs above central ones on benefit, and the central antitussive drugs such as codeine and dextromethorphan showed a lower level of benefit.\n\nAntibiotics are a major concern in acute cough. Acute cough is among the most common reasons for seeking primary care, and up to 85% of cases are erroneously treated with antibiotics—with no impact on recovery. This overuse feeds antibiotic resistance.\n\nChronic cough. Treatment usually targets the identified underlying condition, such as asthma, reflux or postnasal drip, and identifying and treating the cause of a chronic cough can help relieve symptoms and reduce the risk of additional complications. When the cause is not identified, therapy becomes empirical and often less predictable.\n\nNon-drug measures. Evidence for non-drug measures is limited by study design. Almost no studies of nonpharmacologic therapies met these standards."
    },
    {
      "heading": "Research challenges and controversies",
      "text": "Cough is difficult to study. Acute cough is particularly difficult to study in a controlled setting because of the high rate of spontaneous remission and a large placebo effect. Trials in children have been particularly weak; one review found that none of the pediatric studies showed a benefit over placebo for antitussive therapy, antihistamines, decongestants, or antitussive/bronchodilator treatment.\n\nPractice also varies between regions. Across Europe, there are large variations in the recommendations made by healthcare professionals for the treatment of acute cough. Definitions of cough duration also differ among guidelines, which complicates comparison of studies and national statistics."
    },
    {
      "heading": "Burden and public health",
      "text": "Cough is among the most common symptoms in medical practice. It is estimated that as many as 3% of all office visits to primary care physicians in the US are due to cough. Its effects go beyond the respiratory system. It can interrupt your sleep and leave you feeling very tired. Severe cases of chronic cough can cause vomiting and lightheadedness, and even break a rib. Because cough is common and often self-limited, its management also touches on health system costs and on the public-health goal of reducing unnecessary prescribing."
    }
  ],
  "links": [
    "medicine",
    "allergy",
    "gastroesophageal-reflux-disease",
    "cancer",
    "antibiotic-resistance",
    "health-system",
    "public-health"
  ],
  "sources": [
    {
      "title": "The applied physiology of cough - PubMed",
      "url": "https://pubmed.ncbi.nlm.nih.gov/11411375"
    },
    {
      "title": "Cough detector",
      "url": "https://image-ppubs.uspto.gov/dirsearch-public/print/downloadPdf/8771205"
    },
    {
      "title": "Cough Reflex - an overview",
      "url": "https://www.sciencedirect.com/topics/medicine-and-dentistry/cough-reflex"
    },
    {
      "title": "Cough detector",
      "url": "https://image-ppubs.uspto.gov/dirsearch-public/print/downloadPdf/8241223"
    },
    {
      "title": "Chronic Cough - PMC",
      "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC9059861/"
    },
    {
      "title": "The difficult coughing child: prolonged acute cough in children",
      "url": "https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3637271/"
    },
    {
      "title": "Comprehensive evidence-based review on European antitussives",
      "url": "https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4985807/"
    },
    {
      "title": "Chronic Cough",
      "url": "https://www.lung.org/lung-health-diseases/lung-disease-lookup/chronic-cough"
    },
    {
      "title": "Cough reflex - Knowledge and References",
      "url": "https://taylorandfrancis.com/knowledge/Medicine_and_healthcare/Physiology/Cough_reflex/"
    },
    {
      "title": "Longitudinal Study of Children With a Chronic Cough and the Impact of Gastroesophageal Reflux",
      "url": "https://clinicaltrials.gov/study/NCT00771706"
    },
    {
      "title": "The diagnosis and treatment of acute cough in adults - PubMed",
      "url": "https://pubmed.ncbi.nlm.nih.gov/24882627/"
    },
    {
      "title": "Chronic Cough: Causes & Treatment",
      "url": "https://my.clevelandclinic.org/health/symptoms/15048-chronic-cough-overview"
    },
    {
      "title": "Cough (acute): antimicrobial prescribing - ClinicalKey",
      "url": "https://www.clinicalkey.com/#!/content/nice_guidelines/65-s2.0-NG120"
    },
    {
      "title": "Pharmacologic and Nonpharmacologic Treatment for Acute Cough Associated With the Common Cold - CHEST",
      "url": "https://journal.chestnet.org/article/S0012-3692(17)31408-3/fulltext"
    },
    {
      "title": "Treatment of Acute and Subacute Cough: What Works, What Doesn't",
      "url": "https://www.consultant360.com/content/treatment-acute-and-subacute-cough-what-works-what-doesnt"
    },
    {
      "title": "Clinical Practice Guidelines for Diagnosis and Management of Cough—Chinese Thoracic Society (CTS) Asthma Consortium - PMC",
      "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC6297434/"
    },
    {
      "title": "Cough management: a practical approach - PMC - NIH",
      "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC3205006/"
    },
    {
      "title": "Chronic Cough: Symptoms, Causes & Treatment",
      "url": "https://www.tgh.org/institutes-and-services/conditions/chronic-cough"
    },
    {
      "title": "Chronic cough - Symptoms and causes - Mayo Clinic",
      "url": "https://www.mayoclinic.org/diseases-conditions/chronic-cough/symptoms-causes/syc-20351575"
    },
    {
      "title": "Cough Reflex",
      "url": "https://www.meddean.luc.edu/lumen/meded/elective/pulmonary/cough/cough.htm"
    },
    {
      "title": "Chronic Cough",
      "url": "https://www.wakehealth.edu/condition/c/chronic-cough"
    }
  ],
  "license": "https://creativecommons.org/licenses/by/4.0/"
}