Understanding Phlegm: Health Indicators and When to See a Doctor

Updated : Jul 28, 2025 11:20
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Editorji News Desk

Canberra, Jul 28 (The Conversation) Phlegm, also known as mucus, snot, sputum, catarrh, or booger, is a familiar companion when we're under the weather. An increase in its production or a change in its thickness and color – to white, green, yellow, or brown – can tell us much about our health. Here's what to observe and when it's time to consult a doctor.

Understanding Phlegm We all produce mucus, even when we’re healthy. It acts as a protective barrier for our organs, guarding against external threats. Produced by specific cells in the epithelium—a tissue lining the body’s organs and surfaces—mucus offers lubrication, traps dust and allergens, and contains antimicrobial molecules that fend off bacteria, fungi, and viruses.

Increased Production During Illness The epithelium is a frontline defense against infection. When it detects pathogens like bacteria or viruses, it ramps up mucus production to bolster our defenses. This immune response leads to inflammation, causing excess mucus or mucus hypersecretion, which can lead to congestion in the nasal passages during a cold or in the lungs with a chest infection. Although, the cilia in the epithelium usually manage mucus clearance; infections can impair their function, forcing us to cough or blow our noses.

Allergies trigger a similar overproduction of mucus as the immune system mistakenly reacts to harmless substances. Chronic illnesses such as asthma, cystic fibrosis, and COPD also often result in mucus hypersecretion.

Thicker Mucus When Unwell A change in mucus thickness can accompany illness. Normally, mucus comprises 90-95% water, with proteins and salts making up the balance, resulting in a clear, runny consistency. However, illness often leads to an increase in mucin proteins, making the mucus thicker. This results in congestion, a blocked nose, or post-nasal drip, a frequent cause of coughs.

Significance of Mucus Color White or cloudy mucus often signals early infection or inflammation from allergies or chronic conditions like asthma. As infections progress, mucus can turn green, yellow, or brown, with the color linked to the presence of an enzyme from immune cells. Brown-red phlegm often contains blood due to irritated nasal passages. While normally harmless, coughing up blood, or haemoptysis, warrants medical advice due to potential serious causes like lung infections or cancer. Rarely, black mucus can point to fungal infections or pollution exposure, necessitating a doctor's assessment.

Antibiotics: Are They Necessary? Doctors often inquire about phlegm in their evaluations, using color charts to distinguish between viral and bacterial infections and gauge the need for antibiotics. Though yellow-green mucus might suggest a bacterial cause, it isn’t a definitive guide for antibiotic necessity. Extensive mucus production and a change in its nature signal your body’s attempt to fight an infection. In the short term, staying hydrated and using decongestants can offer relief. Still, if accompanied by prolonged fever, fatigue, or loss of appetite, it’s time to see a healthcare professional. (The Conversation)

(Only the headline of this report may have been reworked by Editorji; the rest of the content is auto-generated from a syndicated feed.)

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