Acute, very contagious childhood disease, typically with bouts of coughing followed by a long, loud inhalation (whoop) and ending with mucus expulsion and often vomiting. Caused by the bacterium Bordetella pertussis, it initially resembles a cold with a short dry cough. Within one or two weeks, coughing bouts begin; this phase usually lasts four to six weeks. Serious complications include bronchopneumonia (pneumonia involving the bronchi), asphyxia, seizures, and signs of brain damage. Treatment is with antibiotics. The pertussis vaccine is usually combined with tetanus and diphtheria toxoids as part of routine childhood immunizations.
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Frequent or severe coughing usually indicates the presence of a disease. Many viruses and bacteria benefit by causing their host to cough, which helps to spread the disease to new hosts. Coughing is classified as acute (of sudden onset) if it is present less than three weeks, subacute if it is present between three and eight weeks, and chronic when lasting longer than eight weeks. A cough can be dry or productive, depending on whether sputum is coughed up. Most of the times, coughing is acute and caused by a respiratory tract infection. Coughing can be triggered by food entering the windpipe rather than the esophagus due to a failure of the epiglottis in patients who have difficulties swallowing. Smoking and air pollution are common causes of coughing. Provided the patient is a non-smoker and has a normal chest X-ray, the three most common causes of chronic cough are asthma, gastroesophageal reflux disease and post-nasal drip. Other causes of chronic cough include chronic bronchitis, heart failure and medications such as ACE inhibitors.
Since cough is a natural protective reflex, suppressing the cough reflex might have deleterious effects, especially if the cough is productive. Nonetheless, coughing might be severe enough (in terms of psychological, physical and social distress) to warrant treatment. This should be targeted towards the cause as much as possible, for example by smoking cessation and discontinuing ACE inhibitors. Some patients may only be worried about serious illnesses, and reassurance may suffice. Cough suppressants (or antitussives) such as codeine or dextromethorphan are frequently prescribed although scientific evidence supporting their use is often of poor quality. Other treatment options may target airway inflammation or may promote mucus expectoration.
The common causes of chronic dry coughing include post-nasal drip, gastroesophageal reflux disease, asthma, post viral cough and ACE inhibitors. 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. Two related conditions are atopic cough and eosinophilic bronchitis. Atopic cough occurs in individuals with a family history of atopy, abundant eosinophils in the sputum, but with normal airway function and responsiveness. Eosinophilic bronchitis is also characterized by eosinophilia in the sputum, without airway hyperresponsiveness or an atopic background. This condition responds to treatment with corticosteroids.
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 intro the windpipe in people with swallowing difficulties.
Cough may also be caused by conditions affecting the lung tissue such as bronchiectasis, cystic fibrosis, interstitial lung diseases and sarcoidosis. Coughing can also be triggered by benign or malignant lung tumors 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.
Coughing may also be used for social reasons, such as the coughing before giving a speech. Cough may also be psychogenic, which is different from habit coughing and tic coughing. Coughing may occur in tic disorders such as Tourette's syndrome, although it should be distinguished from throat-clearing in this disorder.
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 chilli peppers spicy, and might explain why workers in factories with these vegetables can develop a cough.
Research has demonstrated that gargling with a mixture of warm water and salt washes away the layer of mucus on the throat containing bacteria and proteins that cause inflammation, according to the American Academy of Otolaryngology.
^ Arella, A. (nd), Coughing as an Indicator of Displacement Behaviour,