Cough in adults

A cough is a reflex action that tries to clear your airways of mucus (phlegm) and irritants such as dust or smoke. You might cough if you have a cold and your airways are partly blocked by mucus, or if you choke on a piece of food. The cough reflex is an important response that protects your airways and lungs.

Coughs are the most common symptom of an upper airway infection. An average adult has 2 to 4 infections with cough per year, and children have more. Find out about coughs in children.

A cough isn't usually serious and will generally go away within a few weeks. A cough might linger for some time even after your other symptoms have cleared up and you’re feeling better. Although a cough has an important purpose, it can be annoying and disruptive to daily life, work and sleep. 

Most coughs are either non-productive (dry) or productive (wet), depending on what’s causing it. A dry cough doesn't produce any mucus, whereas a wet or chesty cough is when you cough up mucus. You may have a feeling of tightness or congestion in your chest with a wet cough. 

Video: Why do we cough? 

There are many causes of cough, the most common being viral infections such as a cold or the flu. Other common causes include: 

• smoking
• allergies, such as hay fever
• asthma
• bronchitis
• pneumonia
• tuberculosis
• whooping cough
• gastro-oesophageal reflux disease (GORD)
• chronic obstructive pulmonary disease (COPD)
• side effects of some medicines, such as angiotensin-converting enzyme inhibitors (also called ACE inhibitors) such as cilazapril, enalapril and lisinopril.

Rarely, a cough may be caused by:

• pulmonary embolism
• lung cancer
• bronchiectasis.

A cough, with or without other respiratory symptoms such as a fever or runny nose, could also be a COVID infection. Test for COVID-19 and stay home until you’re well again, or sure that it isn’t COVID. 

Duration of cough

An acute cough is present for up to 3 weeks. This is most likely a viral upper airway infection. It may also be caused by an irritant, eg, smoke or allergies. Serious causes may include pneumonia or severe infection. 

A subacute cough is present for 3 to 8 weeks. ​It's most likely post viral (from a recent infection) or flare of an underlying condition, eg, asthma, COPD. 

A chronic cough is present for more than 8 weeks. The possible causes could be underlying conditions eg, asthma, COPD, GORD, bronchiectasis. It could also be a side effect from taking certain medicines.

This information relates to cough in adults. Read more about how this might be different for cough in children. 

Wet versus dry coughs

You will sometimes hear these terms when describing a cough and it can help your healthcare provider decide what the cause of your cough is. 'Wet' means that the cough produces gunky products (mucus or sputum) and may sound rattly whereas a 'dry' cough doesn't produce anything and may sometimes feel more like irritation. Your pharmacist or healthcare provider will advise which medicines are suitable for your type of cough.

Short-term cough

A mild, short-term cough is likely to be due to a viral infection that will get better on its own within a few weeks. You can manage your symptoms by staying hydrated, resting, avoiding smoking, and using over-the-counter remedies that may provide some relief. 

Persistent cough

When a cough lasts longer than 8 weeks, it’s known as a persistent, or chronic, cough. This is when there might be something more serious causing it.  
If your cough isn’t going away, or you’re worried about it, see your healthcare provider so they can help you find out what’s causing it and what you can do.

Video: Cough 

In this video, Dr Shah, a GP, describes the common causes of cough and when you should see your healthcare provider. 

(NHS, UK, 2015)

In most cases, treatment for cough isn’t necessary. You can care for yourself by: 

• resting
• drinking plenty of fluids, warm drinks may help soothe an irritated throat
• sleeping with your head propped up on pillows
• avoiding smoke, and trying to cut down or quit smoking if you're a smoker
• taking antihistamines if you have hay fever
• using your inhaler if you have asthma
• making sure your home or environment is warm and dry.
  
  

Cough medicine and other products

There are a number of cough medicines available on the market. They may be sold in combination with other medicines in cold and cough products, or as cough mixtures or cough lozenges. There's little evidence to suggest that cough medicine is any more effective than simple home remedies (eg, honey, saltwater gargles and warm drinks). Cough medicines aren’t suitable for everyone and may have side effects. Read more about cough medicines.

Examples of adult only cough medicines/products currently available in Aotearoa New Zealand, and how they work include: 

• Expectorants (eg, guaifenesin) – help to loosen and thin mucus, making it easier to cough up and clear from your chest. 
• Muculoytics (eg, bromhexine) – break down thin or sticky mucus, making it easier to clear from your airways.
• Sedating anthistamines (eg, chlorpheniramine, brompheniramine) – reduce mucus and nasal secretions and can help with post nasal drip but may cause drowsiness.
• Nasal decongestants (eg, pseudoephedrine) – shrink swollen nasal passages to ease breathing and reduce nasal drip into your throat.  

If you decide to try any of these medicines please discuss the potential side effects with your pharmacist or doctor. Again please note these should not be used in children under 6 years of age.

 
Antibiotics 

Antibiotics are only prescribed if your cough is caused by a bacterial infection. It’s not helpful for your body if you take antibiotics when you don’t have a bacterial infection, as they can cause unwanted side effects. Taking antibiotics when they’re not necessary also adds to the antimicrobial resistance problem where bacteria change over time and become resistant to treatment. Read more about antimicrobial resistance.  

Salt water 

Rinsing your nose with saline, or salty water, may reduce cough associated with post-nasal drip. Commercial saline products are available or you can make them  at home using ¼ teaspoon salt with 2 cups of cooled, boiled water and applied using a spray bottle or syringe. Read more about saline nasal sprays, drops and rinses. 

Honey

Multiple studies have shown honey or honey-containing products may reduce the frequency and severity of cough. Honey can be taken directly from a teaspoon or added to a drink such as warm water. It's import ant that honey is not given to children under 1 year of age. 

Image credit: Canva

Throat lozenges 

These may temporarily soothe a sore throat or help a dry irritating cough but there's no evidence that they reduce the duration or severity of coughs in general.  

Aromatic rubs 

Aromatic rubs such as eucalyptus oil and menthol are no longer recommended. Read more about vapour rubs.

Ivy leaf extract

This is often found in 'bronchial syrups', these are safe for children and adults and there's some evidence that they reduce the severity and frequency of a cough. 

Zinc

These often taste unpleasant but there is some evidence to suggest that zinc lozenges may reduce the time you have a cough for if you start them in the first 24 hours. Read more about zinc and zinc supplements.  

If your cough is very severe or has lasted for a long time, see your healthcare provider. They’ll examine you and ask you questions about what kind of cough it is, such as whether it’s a chesty (wet) or dry one, when it started and whether you have any other symptoms.  

If they decide that more tests are needed, these might include:

• an X-ray of your chest 
• lung function tests 
• taking a sample of your sputum (mucus or phlegm) to check for bacterial infection.

Possible treatments will depend on what’s causing the cough. These may include:

• using an inhaler if your cough is because of asthma 
• being prescribed nasal steroids or antihistamines if you have sinus disease 
• medicine to reduce stomach acid if reflux is causing the cough 
• changing medicines if one of your regular medicines might be causing the cough. 

Remember to cover your cough and wear a mask when you are out of your home, or around others, so you don’t spread your bugs. You will be most infectious at the beginning of a cold or flu, but bugs can be passed on to others for as long as you have symptoms.

You can reduce your chances of getting a cough by following these winter tips for staying well.