Overview
What is a cough?
A cough is the body’s own way of reacting to an irritant in your throat or airways. It is a reflex action to rid your airways of excess mucus, dust particles, or smoke. A cough is a natural response and is not something to be worried;unless, it becomes persistent, and you begin to cough up green-coloured mucus.
A cough can either be acute or chronic. Acute coughs appear abruptly and usually last between 3-8 weeks. A chronic cough can persist from 8 weeks up to an entire lifetime.1
Types of cough
There are mainly two types of coughs
A dry tickly cough and a mucus cough, also known as a productive cough or a wet cough.
Dry coughs indicate the presence of irritants (i.e. smoke or dust particles) in the airways. A dry cough as the name suggests does not involve phlegm production (sticky mucus). It usually does not last very long, and treatment is not required.
A wet cough is when there is a buildup of phlegm in the airways of the lungs. The severity of this cough depends on the thickness of the mucus.
Causes of a mucus cough
So, what is mucus?
Mucus is a fluid-like substance produced by the body which serves as a protective barrier to prevent dust particles, bacteria, viruses, and debris from entering the airways. When you breathe in these particles, they end up sticking to the mucus which then gets passed as stool. Mucus provides lubrication to the lining of the airways and protects from inflammation. Essentially, the presence of mucus in the airways is vital in protecting the airways from drying up and also from the invasion of pesky bugs. Mucus becomes problematic when a type of mucus known as phlegm (sticky and thick) is produced in the lungs, reducing the surface area for air to pass through easily. This can cause complications with breathing.2 Phlegm (derived from the Greek word to mean “inflammation”) is produced when your body sends its natural defenders (white blood cells) to get rid of a foreign element such as bacteria, particles, smoke, virus, etc within the lungs.
Reasons for increased mucus production include :
- Allergies
- Asthma
- Lung diseases such as acute bronchitis, pneumonia, and Chronic Obstruction of Pulmonary Disorder (COPD)
- Viruses such as Coronavirus/ Covid-19
- Infections such as common cold
Increased mucus production can also be caused by the following lifestyle factors:
- Excessive smoking
- High consumption of alcohol and caffeinated beverages
- Predominantly eating foods high in acidity such as red meats and dairy
Having a constant cough, especially for those suffering with COPD and other chronic lung conditions, can greatly affect their quality of life.2
Diagnosis of a mucus cough
The characteristic of a cough can vary between people which then impacts upon symptoms and diagnosis. A healthcare professional can usually diagnose a mucus cough based on the sound of your cough. A wheezy, raspy cough would suggests a build-up of phlegm in your lungs. Additionally, the colour of the phlegm can indicate whether there is an infection present.
Yellow-coloured phlegm suggests that neutrophils and macrophages (white blood cells) are present in the lungs fighting away the foreign invaders.
Green-coloured phlegm suggests that there is an infection present and your doctor may prescribe antibiotics to help clear this up.
Treatment for a mucus cough
Treatment for a mucus cough may vary depending on the severity of the cough and how it is impacting your breathing. When you cough, the ability for you to easily clear your chest is dependent on the thickness of the phlegm. The thicker the phlegm, the harder it is to be carried out of the lungs via the cilia (hair-like structures that brush things along in the lungs) when you cough. Some mucus coughs such as those caused by a common cold can be treated at home using natural home remedies, however, in some cases medication is required to clear the mucus and manage symptoms.
Natural and home remedies
Hydration
Keeping hydrated is very important when you have a mucus cough. This is because water helps to thin-out mucus and aids in what is known as mucociliary clearance. Mucociliary clearance is the mechanism by which the cilia removes insoluble particles from the airways.3 Keeping to the recommended daily intake of about 8 glasses a day will help manage your symptoms and clear your chest.
Humidifiers
The use of humidifiers is also beneficial to a mucus cough for the same reason as drinking plenty of water. The water particles generated as steam from the humidifier help loosen up the mucus enabling you to cough it up and breathe easier. Research shows that the use of warm humidification improved mucus clearance, especially in patients with chronic lung conditions.4 If you don’t have a humidifier, a hot steamy shower will also do the trick.
Dietary changes
Research shows that adopting a predominantly plant-based diet can help improve overall lung health. There is evidence to suggest that the pungent flavour elements in edible plant extracts can stimulate the mucus membranes of the respiratory tract to fight microbes and foreign matter in the airways.5 Foods high in acidity, such as red meats and dairy, should be limited to prevent excess production of mucus in the body.
Medications
Expectorants (Cough medicines) especially the ones that contain Guaifenesin, are typically used in clearing a mucus cough and can be bought over the counter. However, there is evidence to suggest that they are ineffective in clearing phlegm and treating sputum retention for those with chronic lung conditions.6 Instead, it is implied that the use of Hypertonic saline delivered via a nebuliser is more effective in clearing mucus. This is because saline contains salt which attracts water into the airways, therefore thinning the mucus.7 Gargling with warm salt water may also be beneficial to breaking down and clearing thick mucus, however, it isn’t as effective as using a nebuliser.8
Your doctor may also prescribe a Mucolytic such as Carbocisteine which breaks down the mucus strands thus loosening the secretions and making it easier for the mucus to pass through the lungs.9
Antibiotics
If you are coughing up thick green-coloured mucus, it is more than likely that you have a bacterial chest infection and therefore your doctor will prescribe antibiotics to help clear the infection.
Prevention
There are several things you can do to prevent a mucus cough from worsening:
- Keep hydrated.
- Adopt a healthy balanced diet.
- Eat more fruit and vegetables.
- Keep active
When to see a doctor
Seek medical advice if:
- You develop a persistent cough
- Begin coughing up blood
- Your phlegm is green coloured and you have a high fever.
Summary
Mucus acts as a protective barrier in shielding the airways from unwanted particles and pollutants. Phlegm, which is a type of sticky mucus, is produced as a defence mechanism when foreign matter is detected in the airways. It is this phlegm that is attributed to what's known as a mucus cough or wet cough. There are several natural home remedies that can help clear phlegm such as the use of humidifiers and keeping hydrated. In some cases, the phlegm begins to build up and becomes too thick and difficult to cough up, especially in people with lung disease. Medications such as saline nebulisers, carbocisteine and Guaifenesin (Cough syrup) can be used to help clear and loosen thick mucus. The most effective is the use of saline nebulisers and humidifiers. Lifestyle changes such as adopting a healthy balanced diet consisting predominantly of fruit and vegetables can also help to improve lung health.
References
- Cook N, Gey J, Oezel B, Mackay A, Kumari C, Kaur V et al. PRS99 - IMPACT OF COUGH AND MUCUS ON THE EMOTIONAL AND PSYCHOSOCIAL WELLBEING IN PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE: A QUALITATIVE PATIENT ONLINE BULLETIN BOARD STUDY. Value in Health. 2018;21:S420.
- McGarvey L, Rubin B, Ebihara S, Hegland K, Rivet A, Irwin R et al. Global Physiology and Pathophysiology of Cough. Chest. 2021;160(4):1413-1423.
- Bennett W, Kala A, Duckworth H, Zeman K, Wu J, Henderson A et al. Effect of a single 1200 Mg dose of Mucinex ® on mucociliary and cough clearance during an acute respiratory tract infection. Respiratory Medicine. 2015;109(11):1476-1483.
- Herrero-Cortina B, Alcaraz V, Vilaró J, Torres A, Polverino E. Impact of Hypertonic Saline Solutions on Sputum Expectoration and Their Safety Profile in Patients with Bronchiectasis: A Randomized Crossover Trial. Journal of Aerosol Medicine and Pulmonary Drug Delivery. 2018;31(5):281-289.
- Kumar S, Binu A, Devan A, Nath L. Mucus targeting as a plausible approach to improve lung function in COVID-19 patients. Medical Hypotheses. 2021;156:110680.
- Hasani A, Chapman T, McCool D, Smith R, Dilworth J, Agnew J. Domiciliary humidification improves lung mucociliary clearance in patients with bronchiectasis. Chronic Respiratory Disease. 2008;5(2):81-86.
- Webster M, Tarran R. Slippery When Wet. Cell Volume Regulation. 2018;:293-335.
- Lindsey T, Gillette B. The Effectiveness of Saltwater Gargling on the Prevention of Upper Respiratory Tract Infections. OFP [Internet]. 2021Jul.7 [cited 2022Sep.16];13(4):19–23. Available from: https://ofpjournal.com/index.php/ofp/article/view/761
- Lim S, Mohamed S. Functional food and dietary supplements for lung health. Trends in Food Science & Technology. 2016;57:74-82.