Phlegm is also known as mucus and it is produced by your lungs to line the airways and protect them from foreign substances. It also provides moisture which helps to trap irritants and remove them from the body. In certain situations, your body might increase the production of mucus, for example, when you have an allergy or an infection, and that might cause you unpleasant symptoms.
When you cough up phlegm from the lungs or back of the throat, it's often referred to as sputum. Looking at your phlegm or sputum can give you a lot of information about what could be causing your symptoms.
Phlegm can be caused by a number of conditions. It can be caused by acute conditions such as viral, bacterial or fungal lung and airway infections or allergic responses such as allergic rhinitis.
Smoking is a very common cause leading to the production of excess phlegm. Chronic conditions such as COPD (chronic obstructive pulmonary disease), cystic fibrosis, congestive heart failure and gastro-oesophageal reflux disease can also cause this symptom.
Pulmonary embolism (a clot in the lungs), an abscess, or cancer of the lungs are also more serious causes.
If the phlegm is a yellow or green colour, this can be a sign of an infection of the airways. In some cases you can monitor it for a few days to see how your symptoms develop before you seek medical advice.
Brown, red or pink phlegm are normally signs of some blood, old or new. This should be discussed with your doctor, especially if it persists and you feel unwell with it. This can be a sign of bacterial infections, lung abscesses, or even more serious causes such as cancer or a clot in the lungs.
White phlegm can occur with viral infection of the airways, congestive heart failure or chronic lung disease. Similarly, clear phlegm can also be an indication of viral infections or as a result of an allergic response.
When we produce too much phlegm it can become disturbing and cause difficulty breathing. It may also irritate the back of the throat when you are lying down and cause you to cough more, especially at night.
Simple things at home can help to relieve the symptoms of excess phlegm. Improving hydration by drinking more water helps your body stay adequately hydrated and effectively clear away any excess phlegm.
A humidifier moistens the nasal passages and the back of the throat and reduces the amount of phlegm produced. It's important to ensure that dust is removed properly and air filters are cleaned regularly to reduce the build-up of irritants. Nasal saline sprays drop or irrigation with saline solution helps to rinse out any excessive build-up in the nasal system. It is strongly advised to stop smoking if this applies to you.
Changes to the colour of your phlegm, frothy phlegm or phlegm that is causing you significant distress or worry should be followed up with your doctor. Phlegm alone may not provide the full picture and so if you develop any other symptoms, especially difficulty breathing, weight loss, fevers, poor appetite, bleeding from anywhere, it is important that you seek urgent medical attention.
Your doctor may organise further investigations to help understand the cause. If you think this may be occurring due to an allergy, you can speak to your doctor about allergy medications or arranging allergy tests. If there is concern about your lungs, your doctor may arrange some blood tests, a sample of your sputum, which can be sent off for further testing and imaging such as a chest X-ray or CT scan. They may arrange lung function tests to determine the cause.
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