Cough

What is a cough?

Coughing is a protective reflex. It can remove substances that may have been inhaled, such as dust, and excess secretions that have built up in the airways. Coughing is how the body cleans the lungs and airways.

Coughs may be dry coughs or chesty coughs. A dry cough does not produce any mucus or phlegm. A chesty cough (‘productive’ or ‘wet’ cough) is one that produces mucus and may cause feelings of congestion in the chest.

Unexplained coughing that lasts for more than 3 weeks may indicate that you have an underlying medical condition. You should always see your doctor if this is the case.

Coughing is one of the most common symptoms of COVID-19 — even if your cough is mild you should get tested for COVID-19 immediately.

What symptoms are related to a cough?

The symptoms accompanying a cough will vary depending on what is causing it.

Cough is a common symptom for colds and the flu. In general symptoms are more intense with the flu.

These upper respiratory tract viral infections usually cause a dry cough, sore throat and runny nose, although the nose may be blocked to start with. The cough may be tickly and irritating. You may have watery eyes and headache. The common cold may also cause sneezing. Flu may cause fever and chills, if severe, and muscle pains.

A cough due to COVID-19 may be accompanied by other symptoms, such as loss of taste or smell, fever or chills, breathlessness or sore throat. If you experience any of these symptoms you should get tested immediately.

Some people with asthma may have an ongoing cough. Their airways are inflamed and become oversensitive to asthma triggers. The cough is usually a dry cough, and there may also be wheezing. Asthma cough can be worse at night.

A chesty cough produces thick mucus known as phlegm. This is also known as a productive cough or wet cough. The phlegm comes up from the lungs and lower airways. This type of cough may be worse in the morning. There may be wheezing when you breathe in. A chesty cough may follow a common cold infection or can be due to long-term conditions, such as bronchiectasis, chronic bronchitis or asthma.

Whooping cough (pertussis) can result in coughing fits, and there can be a loud ‘whoop’ noise at the end of the cough when the person tries to breathe in again. They may vomit afterwards.

What causes a cough?

Short-term cough

The most common cause of a short-term (acute) cough is a viral infection of the upper respiratory tract, such as in the common cold or the flu. The viral infection inflames the throat, windpipe (trachea) or lungs. In healthy people, this type of cough normally goes away on its own within 2-3 weeks.

Other causes of short-term cough (lasting less than 3 weeks) include:

• COVID-19
• laryngitis — an inflammation of your voicebox (larynx) from infection, overuse or irritation
• sinusitis
• whooping cough (pertussis)
• infections in the lower respiratory tract, such as bronchitis and pneumonia
• asthma that is not well controlled

Persistent cough

A persistent cough (lasting more than 8 weeks) is also known as ‘chronic cough’. It may be caused by an underlying disease, or sometimes the cough reflex may become sensitised and a person develops an ongoing cough.

Some of the causes of persistent cough are:

• postviral cough — following a viral respiratory tract infection, such as sinusitis or bronchitis
• asthma — this may be ‘cough-variant asthma’
• reflux (GORD) — where stomach acid comes up into the oesophagus, irritating it
• ongoing sinusitis or post-nasal drip (upper airway cough syndrome) — where mucus drips down the throat from the back of the nose or sinuses
• habit cough (now known as somatic cough syndrome) — where there is no underlying disease that is causing the cough. Habit cough occurs most commonly in children, and goes away when the child is asleep
• Chronic Obstructive Pulmonary Disease (COPD) — ongoing obstruction of the airflow in the lungs that interferes with breathing
• whooping cough (pertussis)
• tuberculosis
• lung cancer or cancer of the larynx
• obstructive sleep apnoea — a common sleep disorder which results in snoring and stop-start breathing during sleep
• bronchiectasis — where the airways are damaged and can’t clear mucus effectively, leading to chest infections and a productive cough (‘phlegm cough’)
• cystic fibrosis — productive cough
• some medicines — including ACE inhibitors and beta blockers. Alternative medicines may be available without the side effect of cough
• heart failure — a condition where your heart muscle is weak and can’t pump blood around your body effectively

When should I see my doctor?

Please seek medical attention if:

• you have a cough that lasts for more than 3 weeks
• you are short of breath or have chest pain or unexplained tiredness
• you cough up blood, mucus, or phlegm
• you have trouble sleeping because of coughing
• you have unexplained problems like weight loss or a fever

If your child has a cough, please see a doctor if they have:

• a cough that starts suddenly — it may be due to an inhaled foreign body
• a cough that lasts longer than 2 weeks, with or without a cold
• a cough that interferes a lot with their sleep or daily life
• difficulty with breathing
• a high fever
• lethargy (sleepiness and fatigue) and appear unwell
• fewer wet nappies than usual or are not drinking much
•  
• has a change in skin colour, turning blue or very pale
• is having significant breathing difficulties
• is drowsy or unresponsive
• is choking

How is a cough treated?

If you have a persistent cough, your doctor will want to treat any underlying condition that is causing the cough. There may also be triggers that make the symptoms of a persistent cough worse.

Smoking or breathing in other people’s smoke is one trigger that can make cough symptoms worse. Try to avoid being around people who are smoking. If you are a smoker, try to cut down or quit. For advice on quitting smoking, visit the Quit Now website.

Most short-term coughs are due to viral infections of the upper respiratory tract. Most of the time these coughs will go away on their own. Antibiotics do not help because they don’t kill viruses, and may do harm in these circumstances. However, there are some things you can do to relieve the symptoms:

• stay well hydrated — it’s important to drink plenty of water. If you have an existing medical condition, check with your doctor about how much water is right for you.
• rest and avoid vigorous activity until symptoms go away.
• Smoking or breathing in other people’s smoke can make symptoms worse. Try to avoid being around people who are smoking. If you are a smoker, try to cut down or quit. For advice on quitting smoking, visit the Quit Now website.
• have some honey — it may help to reduce the severity and duration of a cough. One to 2 teaspoons of honey taken 30 minutes before bedtime may be helpful. It has been shown to help children with cough — but should never be given to children aged under 12 months.
• find out more about self-care tips if you have a high temperature (fever).

There are many cough remedies and over-the-counter medicines for cough, but they are not generally helpful in treating short-term cough and may have side effects.

Cough medicines should not be given to children aged under 6 years. The Australian Therapeutic Goods Administration has advised that cough and cold medicines (including cough suppressants, antihistamines, decongestants and combination products) should NOT be given to children less than 6 years as they may cause harm, and there is little evidence of their benefits.

Cough and cold medicines should only be given to children aged 6 to 11 years on the advice of a doctor, pharmacist or nurse practitioner.

Unfortunately, many common cold and cough remedies don’t have good evidence to support their use, including vitamin C, salt therapy, steam inhalation and humidifiers. As mentioned, honey has been shown to be helpful for children (over 12 months) with cough.

How can I prevent a cough?

You can’t prevent a cough caused by cold, flu or COVID-19. However, you can minimise your chances of catching these viral infections in the first place, by practising good hand hygiene, physical distancing, and by getting vaccinated (against COVID-19 and influenza). Cough etiquette and staying home when sick are also important in stopping the spread of respiratory viruses.

If a cough is caused by asthma, appropriate asthma treatment can help it. If you think a cough is caused by a side effect of a medicine, see your doctor — alternative medicine may be available.

Tobacco smoke is a significant trigger for cough, so avoiding cigarette smoke (and other environmental triggers) can help prevent cough in both adults and children.

What are some complications of a cough?

An ongoing or vigorous cough can cause complications, including:

• sleep disruption
• headache
• hoarseness and laryngitis
• urinary incontinence
• back and chest pain
• fractured rib