A cough is a normal bodily response that’s designed to clear mucus and other irritants from the lungs.
In most cases, it’s nothing to worry about and gets better on its own. Sometimes, however, a cough can be a sign of a condition that needs medical attention.
But how can you tell when it’s time to worry about a cough? The length of time you’ve had the cough often provides a clue.
Types of coughs
A cough can be defined by how long it lasts. The different types are:
- acute coughs - last for less than 3 weeks
- subacute coughs - last for 3 to 8 weeks
- chronic coughs - last for more than 8 weeks
An acute cough is usually caused by a viral illness like the common cold. It typically clears on its own after a couple of weeks. However, subacute and chronic coughs should always be assessed by a doctor.
When to see a doctor about an acute cough
An acute cough is usually caused by a viral infection of the nose, sinuses and/or throat (known as the upper respiratory tract). These are infections like a cold or the flu. But a cough can also be caused by infections or inflammation of the lungs and airways, such as acute bronchitis or pneumonia.
An acute cough can also be triggered by an allergy or a flare-up of a long-term condition like asthma.
This type of cough can usually be treated at home with plenty of rest and fluids. However, see a doctor if:
- your cough is severe or getting worse, or you’re constantly coughing or have a hacking cough
- you feel very ill
- you have chest pain
- you are losing weight without trying to
- you have swollen glands (feel the side of your neck to check for swelling)
- you’re finding it difficult to breathe
- you have a weakened immune system (e.g. caused by chemotherapy or conditions like diabetes)
You should seek immediate medical help if you’re coughing up blood.
When to see a doctor about a subacute or chronic cough
If you’ve had a cough for more than 3 weeks, see a doctor. Your cough may be caused by conditions, including:
- gastro-oesophageal reflux disease (GORD)
- chronic obstructive pulmonary disease (COPD)
- postnasal drip
- certain medications
In rare cases, a persistent cough can be a sign of a more serious underlying condition.
When to see a doctor urgently
If you’re coughing up blood you should see a doctor urgently.
A cough is not usually anything to worry about, and should clear up on its own within 3 to 4 weeks. However, if you experience any of the concerning symptoms mentioned in this article or you’re worried about your cough, see a doctor.