What are the most common causes of chronic cough?
There are many possible causes of cough but the following are the most common.
Cigarette smoke is irritant to the lining of the airways, so being a smoker, or being around other people smoking (being a passive smoker) is a common cause of cough. Smoking-related coughs are usually dry - in other words you don't cough anything up - and tend to be worst in the mornings.
A group of medicines called angiotensin-converting enzyme (ACE) inhibitors commonly cause a cough. Examples of commonly used ACE inhibitors are lisinopril, ramipril, trandolapril and perindopril. If these medicines cause a cough, they can usually be replaced with other treatments. Some other medicines can also occasionally cause a cough. Cough caused by ACE inhibitors also tends to be a dry cough.
Catarrh coming from the back of your nose
Any condition which gives you more gunk in your nose may result in that gunk dripping down the back of your throat and making you cough. Examples of conditions which could do this are allergies, persistent rhinitis and nasal polyps. This is called postnasal drip or upper airway cough syndrome. It tends to be worse in the morning and then improve during the day, and you usually cough up some mucus, which has originally come from your nose.
Often if you have acid reflux, you are aware of it and get a burning sensation in your gullet, called heartburn. However, sometimes a cough is the only symptom of acid coming back (refluxing) up from your stomach. The stomach acid irritates the upper part of the airway around the voice box (larynx) and causes a cough. This kind of cough is sometimes worse after eating, or whilst you are eating. It may also be worse when you bend over, or while you are lying flat in bed.
Usually the cough of asthma comes with other symptoms, such as being out of breath when you exercise, or having wheezy breathing. Asthma can start with just a cough, however. The cough tends to be worse during the night, or when you exercise.
Chronic obstructive pulmonary disease (COPD)
The cough of COPD usually comes with gradually worsening breathlessness when you do anything. Colds often progress to coughs which turn into chest infections and linger. It is usually caused by many years of smoking.
Could it be cancer?
You and your doctor will always want to rule out cancer if you have a cough which lingers. Lung cancer is more likely if you have been a smoker, but can occur in anyone. Signs that it might be cancer include losing weight and coughing up blood. You may also have pain in your chest or shoulder. Lung cancer is not one of the most common causes of persisting cough, but it is definitely one to check out.
Other types of cancer in the lungs can also cause cough, such as:
- A spread of cancer from a cancer elsewhere (secondary tumours or metastases).
- Lymphoma - a cancer of the bloodstream.
What are the less common causes of chronic cough?
Other possible causes include:
- Tuberculosis (TB). This is still very common in some parts of the world, although not seen very often in the UK.
- Bronchiectasis. Usually if you have this condition, you bring up a lot of phlegm when you cough.
- Having something (a "foreign body") stuck in the airways.
- Whooping cough (pertussis). This cough tends to linger for a long time, although it has usually gone by eight weeks. There are characteristic bouts of coughing, followed by a "whoop" as you catch your breath.
- Heart failure. This means your heart isn't pumping as efficiently as it should do. Usually symptoms are being short of breath, tired and having swollen ankles. Occasionally there can be a cough.
- Interstitial lung disease. This is a scarring of lung tissue, which causes cough and breathlessness.
For more information on these conditions, follow the links where available.
Will the cause always be found?
Nope, sorry, not always. All the above conditions can be ruled out in some cases, but still leaving the cough behind. Sometimes you can be left with an unexplained cough. There are various names for this, including:
- Idiopathic cough. (Idiopathic means there is no cause to be found.)
- Chronic refractory cough.
- Cough hypersensitivity syndrome.
- Neurogenic or psychogenic cough.
Further reading and references
Cough; NICE CKS, June 2015 (UK access only)
Barraclough K; Chronic cough in adults. BMJ. 2009 Apr 24338:b1218. doi: 10.1136/bmj.b1218.
Johnstone KJ, Chang AB, Fong KM, et al; Inhaled corticosteroids for subacute and chronic cough in adults. Cochrane Database Syst Rev. 2013 Mar 28(3):CD009305. doi: 10.1002/14651858.CD009305.pub2.
Gibson PG, Vertigan AE; Management of chronic refractory cough. BMJ. 2015 Dec 14351:h5590. doi: 10.1136/bmj.h5590.
Faruqi S, Murdoch RD, Allum F, et al; On the definition of chronic cough and current treatment pathways: an international qualitative study. Cough. 2014 May 2910:5. doi: 10.1186/1745-9974-10-5. eCollection 2014.
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