Phlegm is a type of mucus produced in the respiratory system, specifically within the lungs and throat. It serves a protective function, trapping irritants, allergens, and pathogens like bacteria and viruses. While the body naturally produces about a quart of mucus daily to lubricate airways and clear particles, excessive phlegm can indicate an irritation, infection, or inflammation. When phlegm is expelled through coughing, it is often referred to as sputum.
Common Reasons for Increased Phlegm
Increased phlegm production often signals the body’s response to various common conditions, particularly infections and allergies. Excess mucus dripping down the back of the throat is known as postnasal drip.
Infections, both viral and bacterial, are common causes. Viral infections, such as the common cold, flu, or bronchitis, trigger inflammation in the airways, causing the body to produce more mucus to trap and remove the virus. For example, acute bronchitis leads to increased mucus. Phlegm may initially be clear or white, potentially becoming yellow or green if the infection progresses or a secondary bacterial infection develops. Bacterial infections like sinusitis also cause inflammation and increased mucus, which can appear yellow or green due to white blood cells fighting the infection.
Allergies are another frequent cause. When an individual encounters an allergen, the immune system releases chemicals like histamine, leading to inflammation and increased mucus production in the nasal passages. This excess mucus, often clear, can trickle down the back of the throat as postnasal drip, causing irritation and a persistent urge to clear the throat or cough.
Exposure to environmental irritants also stimulates phlegm production. Substances such as smoke, air pollution, dust, and chemical fumes, can irritate the respiratory lining. The airways react by producing more phlegm to trap and expel these harmful particles.
Insufficient fluid intake can also contribute to the perception of excessive phlegm. Dehydration causes existing mucus to become thicker and stickier, making it more difficult to clear. Staying adequately hydrated helps to thin the mucus, facilitating its removal.
Less Obvious Reasons for Increased Phlegm
Beyond common acute conditions, certain chronic or less apparent factors can lead to persistent excess phlegm. Gastroesophageal Reflux Disease (GERD) is one such condition, where stomach acid flows back into the esophagus. This acid can irritate the throat and airways, prompting the body to produce more mucus. Individuals with GERD might experience a constant sensation of phlegm in their throat, along with other symptoms like heartburn or frequent throat clearing.
Asthma, a chronic inflammatory disease of the airways, often involves increased mucus production. During asthma flare-ups, the airways become inflamed, swell, and produce excess mucus, which can contribute to airway obstruction and make breathing difficult.
Chronic Obstructive Pulmonary Disease (COPD) is another long-term condition characterized by persistent phlegm production. In COPD, the airways become damaged and inflamed, leading to increased mucus that can clog the airways. This condition, often linked to long-term exposure to irritants like cigarette smoke, results in a chronic cough that may or may not produce phlegm.
Certain medications can also have increased mucus production as a side effect. Some medications may either increase mucus secretion or make existing mucus thicker and harder to clear.
When to Consult a Healthcare Professional
While occasional phlegm is normal, certain characteristics or accompanying symptoms warrant medical evaluation.
Phlegm Color
Changes in the appearance of phlegm can provide clues about its underlying cause:
Yellow or green phlegm often indicates an infection.
White phlegm can be associated with viral infections, allergies, or GERD.
Brown phlegm may suggest old blood or chronic conditions like cystic fibrosis or bronchiectasis.
Pink or red phlegm indicates fresh blood, which could be a sign of infection or, rarely, more serious conditions.
Frothy white phlegm can signal conditions like pneumonia, COPD, or GERD.
Accompanying Symptoms
Seek medical attention if increased phlegm is accompanied by:
Fever
Shortness of breath
Chest pain
Wheezing
Difficulty swallowing
Unexplained weight loss
Persistent hoarseness
Duration and Impact
If phlegm production lasts for more than two to three weeks without improvement, or if a persistent cough with phlegm does not respond to over-the-counter remedies, consult a healthcare provider. Also seek medical advice if phlegm significantly interferes with daily life, such as causing difficulty breathing, disrupting sleep, or impacting routine activities. Individuals with pre-existing chronic respiratory or heart conditions, such as asthma or COPD, should consult their doctor if they experience a significant or worsening increase in phlegm, as this could signal a change in their condition.