What's causing that cough? 10 causes and how to deal with them

So your cold's long gone, but have you now been left with a lingering cough that is keeping everyone awake and annoying colleagues? New US research shows the average time for a cough to last after a virus is an exhausting 18 days - with many coughs sticking around even longer. GPs admitted they have been inundated over the winter with patients complaining that they just can't shift their persistent coughs, so what can you do? "Coughing actually has an important purpose," explains Professor Ron Eccles, director of the Common Cold Centre at Cardiff University. "It's your body's way of keeping unwanted stuff from getting into your lungs. But unfortunately, post-virus, this irritating symptom can really linger. "The majority of viral coughs are safe to treat at home, but you may need your GP's help to shift it if it develops into a secondary chest infection." However, some persistent coughs aren't viral at all. "Anything still bashing away after three weeks needs investigating," says Professor Stephen Spiro, medical adviser with the British Lung Foundation. "Prolonged coughs can be a sign of anything from asthma and heartburn to more serious lung disease - especially in smokers who often wrongly assume their cough is just par for the course." Here are the 10 most common cough causes - and their treatments. Post-viral cough Symptoms: An irritating cough following a cold. Causes: It's normal to have a cough with a virus, as it's triggered by mucus draining down the back of the throat. The inflammation this causes often stays long after the initial illness. Treat it: Some 90% of cases aren't bacterial, so antibiotics won't help. Prof Eccles advises using an over-the-counter syrup (try Covonia Chesty Cough Mixture, £3.98, from chemists) to loosen phlegm, or even just a hot drink, which promotes secretions in the airways, soothing irritation. If your sinuses are still inflamed, your GP can prescribe a steroid nose spray. Asthma Symptoms: A chronic dry cough that's worse at night, disturbing sleep, and sometimes with wheezing and shortness of breath. Causes: An irritating night cough is often the first sign of asthma, especially in children, but you can develop it at any age. It's also a sign asthma is worsening or not being well controlled. Treat it: The first thing your GP will try is a blue'reliever' inhaler, which releases medication to open the airways. In more severe cases, a brown 'preventer' inhaler is prescribed, which contains a steroid to reduce airway inflammation. Heartburn Symptoms: A 'throat' cough following a meal, or waking you at night, often with a nasty acid taste in your mouth. Causes: Heartburn, or acid reflux, occurs when stomach acid flows back up the oesophagus, irritating the throat and triggering a cough. Large or rich meals late at night are triggers. Treat it: Sleeping with an extra pillow can help reduce the backflow of acid. If it's occasional, a simple over-the-counter anti-reflux treatment, such as Zantac, will reduce the production of stomach acid. If it's frequent, talk to your GP who may want to investigate. Chest infection Symptoms: A hacking cough with greenish phlegm, plus a fever that follows after a cold. Causes: A chest infection, or acute bronchitis, affects the lower airways. It's generally caused by the same viruses that cause colds, but inflammation spreads lower into the lungs, leaving the area open to attack by bacteria. Treat it: Drink plenty of fluids and take paracetamol to reduce a fever. Because most bronchitis is caused by a virus, your doctor will only prescribe antibiotics if he suspects a secondary bacterial infection has occurred. Whooping cough Symptoms: Uncontrollable coughing fits, which may produce a 'whoop' sound. Causes: This highly contagious disease has been on the rise again in recent years, and spreads when an infected person coughs and another person inhales the bacteria. A vaccine is given to babies and since last year, pregnant women, but protection fades so you can still get it as an adult. Treat it: Babies are at the highest risk of severe complications and death and need close monitoring. In older children and adults it's generally unpleasant, but not serious, lasting up to six weeks. Drink plenty of fluids and take ibuprofen to ease a sore throat. Medication cough Symptoms: A dry, niggling cough, often worse at night. Causes: ACE inhibitors, a drug used to control high blood pressure, can cause a chronic cough in 20% of patients. Treat it: If your cough coincided with starting medication, talk to your doctor who can supply alternative blood pressure drugs. Tuberculosis Symptoms: A persistent cough, often with extreme tiredness, weight loss, night sweats and coughing up blood. Causes: Another highly infectious illness, once thought to be wiped out, current TB rates are the highest for 40 years. Treat it: Because TB awareness is low these days, it's worth mentioning the condition to your GP if your symptoms fit those described above. If they suspect TB you'll have a skin test to check for antibodies and be sent for a lung X-ray. Treatment involves six months of strong antibiotics that cures 99% of cases. Smokers' cough Symptoms: It's easy to get used to a 'smokers' cough' but if it changes in any way, for example, becomes more frequent or you cough up blood, it needs checking out immediately. Causes: Smoking irritates the airways causing a cough, which in the long-term can be a sign of COPD - chronic obstructive pulmonary disease, including emphysema and chronic bronchitis - meaning there's irreversible damage to your airways, worsening if you continue puffing away. Treat it: If you're a smoker or ex-smoker with a persistent cough, your GP should send you for X-ray. It's never too late to quit - giving up will lessen or abolish a smokers' cough in 94% of people within four weeks, and will stop the rate of deterioration in COPD cases. Lung cancer Symptoms: A new cough lasting longer than three weeks, a long-standing cough that gets worse, coughing up blood, unexplained breathlessness, weight loss, tiredness or chest pain. Causes: Lung cancer is now the second most common cancer in the UK and smoking accounts for 90% of cases. Treat it: If an X-ray confirms it, treatment combining surgery, chemotherapy and radiotherapy depends on the stage of the cancer. Heart problems Symptoms: Persistent coughing or wheezing, plus extreme tiredness, breathlessness on exertion and fluid retention. Causes: When you suffer heart failure, fluid can build up in the lungs and cause a lingering cough. Treat it: See your GP immediately. If they suspect heart failure you'll be referred to a specialist hospital clinic for an ECG and blood tests. Treatments include ACE inhibitors to prevent fluid build-up and beta-blockers to slow the heart rate.