Coughs are the soundtrack to winter.

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From playgrounds, offices and shops to public transport, it’s impossible to avoid them.

But if yours has been with you for longer than three weeks, it might be time to book in and see your GP.

Possible causes

Unlike short term coughs which ordinarily clear up within three weeks and are usually caused by colds and minor infections, chronic coughs last longer.

Allergies and asthma - which often comes with wheeziness and shortness of breath - as well as smoking, the weather and the environment, can cause coughs.

The symptoms you experience could be harmless and very rarely are they a sign of a more serious condition like heart failure, lung cancer, tuberculosis or a pulmonary embolism, but it’s always worth seeking a medical opinion.

Make sure you tell your GP if your cough has been getting worse, is accompanied with other side effects such as chest pain, coughing up blood or wheezing, or if you feel very ill, lethargic and have lost weight without trying. 

Be aware that children are more likely than adults to have bronchiolitis – a mild respiratory tract infection causing cold-like symptoms, whooping cough or croup, which causes a barking sound.

Types of persistent cough:

1. Whooping Cough

Causes: Symptoms of this bacterial infection of the lungs and airways usually appear around a week after infection.

Symptoms: Initial mild, cold-like symptoms that develop over weeks into severe coughing fits. Coughs often end with a 'whooping' sound - though not everyone has this - usually followed by a thick phlegm. Babies and young children may also vomit after coughing.

Treatment: Vaccination is the key to controlling this condition, which can be very dangerous in young children. It's much less serious in older children and is rare in adults, and can be treated with antibiotics and over-the-counter remedies. Rest and plenty of fluids are advised for recovery, as is staying away from work/school until five days from the start of the treatment to avoid spreading the infection. Pregnant women are offered a free vaccination from about 20 weeks.

2. Bronchitis

Causes: An infection of the large airways and lungs, causing inflammation.

Symptoms: A hacking cough that brings up yellow-grey or greenish phlegm, and cold-like symptoms including a blocked or runny nose, headache, aches and pains and tiredness.

Treatment: Those who have chronic bronchitis might have the cough long after the other symptoms have disappeared. Acute – or short term bronchitis - is often managed at home with rest and lots of fluids to prevent dehydration and thin the mucus, as well as paracetamol for aches and pains. Antibiotics aren’t usually prescribed.

[Read more: Cough etiquette – 7 ways to make sure you don’t annoy people]

3. Asthma

Causes: It's not clear what causes asthma, but it's thought to be a combination of genetic and environmental factors that cause the bronchi that carry air in and out of the lungs to become more sensitive and swollen. The body responds with an allergic-type reaction. Triggers can include allergens and irritants such as dust mites, smoke and sudden changes in the weather.

Symptoms: Wheezing and a shortness of breath, plus a tight chest and cough.

Treatment: GPs will often prescribe inhalers to relieve and stop the symptoms.

4. Chronic Obstructive Pulmonary Disease (COPD)

Causes: The primary cause is smoking. The smoke scars the lungs and causes the
airways to thicken and more mucus is produced.

Symptoms: Increasing breathlessness, a persistent chesty cough with phlegm, frequent chest infections and wheeziness.

Treatment: Stop smoking. Become more active and eat a healthy diet to prevent infections. Inhalers and medication can also make breathing easier.