Phlegm
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Try one of these related symptoms.
Phlegm
Sputum
Yellow or green sputum
Blood in phlegm
Bloody mucus
Blood-tinged sputum
Coughing up mucus
Coughing up green mucus
Coughing up blood
Bloody cough
Hemoptysis
Expelling mucus
About the Symptom
Phlegm is a form of mucus produced in the lungs. You usually don't produce noticeable amounts of phlegm unless you have a cold or another underlying medical condition. Sputum is the term for phlegm that is coughed up.
When to See a Doctor
Seek professional care if you experience any of the following symptoms
- Repeated fever above 38 ℃
- Peripheral cyanosis
- Difficulty breathing / breathlessness
- Respiratory wheeze
- Fever
Possible Causes
Generally, Phlegm can be related to:
- Bronchiectasis
A condition where the airways of the lungs become abnormally wide. There are various causes, including infections, but sometimes the cause is unknown.
- Lymphangioleiomyomatosis
Lymphangioleiomyomatosis (LAM) results from abnormal growth of muscle cells, particularly in the lungs and lymph system. This can lead to the formation of holes or cysts in the lung and blockage or rupture of lymph vessels, causing lymph and fatty acid accumulation in the chest cavity. It is caused by gene mutations that produce proteins which cannot regulate cell growth and movement in the body.
- Acute / Chronic Tracheitis / Bronchitis
Inflammation of the airways, typically caused by flu viruses spreading to the airways. Symptoms include strong coughing, increased phlegm, fever, and tiredness. It is usually caused by viruses rather than bacteria.
- Cystic Fibrosis (CF)
- Mycobacterial Infections (Excluding TB)
- Tracheomalacia
Related Serious Diseases
Sometimes, Phlegm may be related to these serious diseases:
- Aspergillosis
Aspergillosis is an infection caused by a type of fungus. It typically affects the respiratory system and sinuses, but its signs and severity vary greatly. Aspergillus is present everywhere (indoors and outdoors), which can cause the infection.
- Empyema
- Tuberculosis (TB) (Including Scrofuloderma)
- Pneumonia (Lower Respiratory Tract Infection)
Doctor's Diagnostic Questions
Your doctor may ask these questions to check for this symptom:
- Are you producing phlegm?
- When did you first start producing phlegm?
- How is your phlegm production now?
- Are you producing phlegm that contains blood?
- Do you have yellow or green sputum?
Reviewed By:
Phillip Aguila, MD, MBA (Pulmonology, Critical Care)
Dr. Aguila graduated from West Virginia University School of Medicine. He has trained in Pulmonary and Critical Care Medicine at The University of North Carolina in Chapel Hill and Internal Medicine at Medical College of Pennsylvania/Hahnemann University at Allegheny General Hospital in Pittsburgh Pennsylvania. He has served as Assistant Professor since 2010.
Eisaku Kamakura, MD (Pulmonology)
Dr. Kamakura graduated from the Tokyo Medical and Dental University, School of Dentistry, and the Niigata University School of Medicine. He trained at Yokosuka Kyosai Hospital and held positions in the Respiratory Medicine departments at Yokosuka Kyosai Hospital, Tokyo Medical and Dental University, Ome City General Hospital, and Musashino Red Cross Hospital. In 2021, he became the specially appointed assistant professor at the Department of General Medicine, Niigata University School of Medicine.
Content updated on Feb 6, 2025
Following the Medical Content Editorial Policy
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FAQs
Q.
What are the symptoms of a persistent cough and phlegm after COVID-19?
A.
After recovering from COVID-19, some individuals may experience a persistent cough and phlegm production, which can be part of a condition often referred to as "long COVID" or post-COVID syndrome. The symptoms can vary in severity and duration, and understanding them can help in managing the condition effectively.
References:
Kang YR, Huh JY, Oh JY, Lee JH, Lee D, Kwon HS, Kim TB, Choi JC, Cho YS, Chung KF, Park SY, Song WJ. Clinical Characteristics of Post-COVID-19 Persistent Cough in the Omicron Era. Allergy Asthma Immunol Res. 2023 May;15(3):395-405. doi: 10.4168/aair.2023.15.3.395. Epub 2023 Apr 7. PMID: 37075801; PMCID: PMC10186121.
Watase M, Miyata J, Terai H, Sunata K, Matsuyama E, Asakura T, Namkoong H, Masaki K, Yagi K, Ohgino K, Chubachi S, Kawada I, Mochimaru T, Satomi R, Oyamada Y, Kobayashi K, Hirano T, Inoue T, Lee H, Sugihara K, Omori N, Sayama K, Mashimo S, Makino Y, Kaido T, Ishii M, Fukunaga K. Cough and sputum in long COVID are associated with severe acute COVID-19: a Japanese cohort study. Respir Res. 2023 Nov 14;24(1):283. doi: 10.1186/s12931-023-02591-3. PMID: 37964338; PMCID: PMC10648313.
García-Vicente P, Rodríguez-Valiente A, Górriz Gil C, Márquez Altemir R, Martínez-Pérez F, López-Pajaro LF, García-Berrocal JR. Chronic cough in post-COVID syndrome: Laryngeal electromyography findings in vagus nerve neuropathy. PLoS One. 2023 Mar 30;18(3):e0283758. doi: 10.1371/journal.pone.0283758. PMID: 36996121; PMCID: PMC10062549.
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