Phlegm ( "inflammation, humour caused by heat") is a liquid secreted by the mucous membranes of mammals. Its definition is limited to the mucus produced by the respiratory system, excluding that from the nasal passages, and particularly that which is expelled by coughing ( sputum). Phlegm is in essence a water-based gel consisting of glycoproteins, immunoglobulins, lipids and other substances. Its composition varies depending on climate, genetics, and state of the immune system. Its color can vary from transparent to pale or dark yellow and green, from light to dark brown, and even to dark grey depending on the constituents.
Distinction between mucus and phlegmContrary to popular misconception and misuse, mucus and phlegm are not always the same.
MucusMucus is a normal protective layering around the airway, eye, nasal turbinate, and urogenital tract. Mucus is an adhesive viscoelastic gel produced in the airway by submucosal glands and goblet cells and is principally water. It also contains high-molecular weight mucous glycoproteins that form linear polymers.
PhlegmPhlegm is more related to disease than is mucus and can be troublesome for the individual to excrete from the body. Phlegm is a secretion in the airway during disease and inflammation. Phlegm usually contains mucus with virus, bacteria, other debris, and sloughed-off inflammatory cells. Once phlegm has been expectorated by a cough it becomes sputum.
Excessive phlegm creationThere are multiple factors that can contribute to an excess of phlegm in the throat or larynx.
- Vocal abuse: Vocal abuse is the misuse or overuse of the voice in an unhealthy fashion such as clearing the throat, yelling, screaming, talking loudly, or singing incorrectly.
- *Clearing the throat: Clearing the throat removes or loosens phlegm but the vocal cords hit together causing inflammation and therefore more phlegm. link
- *Yelling/screaming: Yelling and screaming both cause the vocal cords to hit against each other causing inflammation and phlegm. Common Medical Diagnoses and Treatments in Professional Voice Users
- *Nodules: Excessive yelling, screaming, and incorrect singing as well as other vocal abusive habits can cause vocal nodules. See vocal fold nodule for more information on nodules.
- Smoking: Smoke is hot, dry, polluted air which dries out the vocal cords. With each breath in of smoke, the larynx is polluted with toxins that inhibit it from rehydrating for about 3 hours.Davies, Shela, "Sound Advice: Your guide to a strong, clear, easy voice" The vocal cords need a fair amount of lubrication and swell from inflammation when they do not have enough of it. When the vocal folds swell and are inflamed, phlegm is often created to attempt to ease the dryness.
- *Experiment on smoking correlations: In 2002, an experiment was done and published by the American College of Chest Physicians to find if there was a correlation of smokers with coughing and phlegm. In the study, 117 participants were studied, a mix of current smokers, ex-smokers, non-smokers, and a positive control of participants with a disease, COPD ( Chronic Obstructive Pulmonary Disease.) At the end of the experiment, experimenters found that there was a high correlation between phlegm and cough with smoking of 0.49 (p < 0.001.)
- Illness: During illness like the flu, cold, and pneumonia, phlegm becomes more excessive as an attempt to get rid of the bacteria or viral particles within the body. A major illness associated with excess phlegm is acute bronchitis. A major symptom of acute bronchitis is an excess amount of phlegm and is usually caused by a viral infection, and only bacterial infections, which are rare, are to be treated with an antibiotic. link
- Hay fever, asthma: In hay fever and asthma, inner lining in bronchioles become inflamed and create an excess amount of phlegm that can clog up air pathways.
- Air pollution: In studies of children, air pollutants have been found to increase phlegm by drying out and irritating parts of the throat.