When to worry about a persistent cough

As many as 1 in 5 of us have a persistent cough, which is not usually serious but can be exhausting - especially if it stops us sleeping.

What is a persistent cough?

Doctors describe a persistent, or 'chronic' cough as one lasting more than 8 weeks. Three to 8 weeks is 'sub-acute' and fewer than 3 weeks is 'acute', meaning short-term.

The time your cough lasts is important because long lasting (chronic) coughs usually have different causes and treatments to others. Coughs lasting fewer than 3 weeks are usually caused by viruses, and remedies from your pharmacist may help you through them.

When to see a doctor about a persistent cough

See a doctor if your cough persists for more than three weeks or you get other symptoms like shortness of breath, chest pain or coughing up blood. Likewise, if you have a long-term chest condition like asthma or COPD, you need to contact your doctor if the cough has made these symptoms worse.

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What's causing your persistent cough?

A cough can be caused by irritation of the airways anywhere from your throat to the bottom of your lungs. Some are obvious, but you might be surprised at the culprits your GP will point the finger at.

COPD

If you smoke or have smoked, a persistent cough could be due to a long term lung condition called COPD - sometimes called emphysema or chronic bronchitis. If you're over 35, have ever smoked and have a persistent cough, bring up phlegm regularly, get bronchitis in winter, and get wheezy or out of breath, COPD may be to blame. It can be diagnosed easily by a test called spirometry, which involves blowing into a special machine.

Asthma

Asthma usually comes on in childhood but can start later in life. Both can be treated with inhalers, but stopping smoking is still essential. If you don't smoke but work in a smoky atmosphere or with chemicals or fumes, they can irritate your upper airways, causing persistent, tickly cough.

Postnasal drip

Colds, allergies and chronic sinusitis can cause a drip down the back of your throat which irritates your upper airways, especially when you lie down. It may mean you have a permanently blocked nose and a nasty taste in the back of your throat.

Treatments for sinusitis vary depending on how long you've had it, how severe your symptoms are and whether you have polyps - painless soft growths - in your sinuses.

Allergies like hay fever and persistent rhinitis can be treated with nasal sprays and antihistamine tablets. Persistent rhinitis is a constantly blocked nose caused by allergy to house dust, meaning symptoms are often worse in winter and when you're indoors.

Acid reflux

When I talk to people about reflux, they normally think of heartburn - that burning pain behind your breastbone that's worse when you lie flat. It can also give rise to an acid taste in your mouth, and this acid can irritate the throat.

It's one of the most common causes of persistent cough. Solutions include anti-acid medicine, losing weight, avoiding eating late at night, and not wearing tight belts or trousers. Propping the head of the bed up a bit can also help.

Heart problems

If your heart isn't pumping blood around your system as efficiently as it should, it can lead to a build-up of fluid in your lungs. This is called heart failure - although it's not strictly a failure of the heart.

Other pointers to heart failure include shortness of breath on exercise or lying flat; swollen ankles and waking up in the night gasping for breath. The outcome for heart failure patients has improved dramatically in recent years with the advent of new medical treatments.

Some medications

A groups of medicines used very commonly to treat high blood pressure can cause dry, irritating cough in up to 1 in 10 men and 2 in 10 women. They're called the ACE inhibitors and have names ending in '-pril' - for example, enalapril and lisinopril.

Symptoms can start when you've taken them without problem for months or even years. Speak to your GP if you think they may be to blame - there are alternatives that do not cause a persistent cough.

Can cancer cause a persistent cough?

Lung cancer is also linked with persistent coughing - but other causes are much more likely.

Put into yellow box

However, always see a doctor if your cough lasts for more than three weeks, or is accompanied by any of the following:

• Coughing up of blood or rusty-coloured phlegm.

• Wheeziness or difficulty in breathing.

• A sharp stabbing chest pain when you breathe - rather than when you cough.

If you do have difficulty in breathing or a chest pain, call for an emergency ambulance immediately - 999 in the UK.

The National Institute for Health and Care Excellence (NICE) has guidelines on when cancer should be suspected. They recommend you should have a chest X-ray within two weeks if you're over 40 and have two symptoms out of cough, shortness of breath, tiredness, chest pain, weight loss or loss of appetite.

If you're over 40 and have ever smoked, just one of these symptoms should trigger a referral for chest X-ray. However, this is only if the symptoms are unexplained. For example, having a cough for a week or two accompanied by other symptoms of infection with a virus - such as a runny nose or fever - does not raise the same alarm bells.

Trust your pharmacist

Most coughs that accompany a cold will settle in one to two weeks. It's not uncommon to be infected with more than one virus at the same time, so symptoms may overlap and last longer from start to finish. They're almost all caused by viruses, so antibiotics do not do any good at all. In fact, we can't cure them, but there are a lot of things that you can do to help relieve the symptoms.

Your pharmacist can advise you on all sorts of remedies, depending on what combination of symptoms you have. For instance, with a chesty cough you bring up yellow or green phlegm or mucus, while a dry, tickly cough usually doesn't come with any phlegm.

Being cold for long periods may increase the chance of illnesses like chest infections - so don't sleep with the window open. However, there's no reason to avoid going out entirely if you have a cold, as long as you're well wrapped up.