Are you sick of phlegm?
Have you heard, "There's a bug going around?" What does that really mean? Often it refers to a virus but it may also indicate a bacterial infection.
Some people have flu-like symptoms. There can be chills, body aches, fatigue and fever. Pulmonary and nasal passages may get involved with a sore throat, sneezing or coughing.
Today, let's talk more about that pesky cough. Coughing is an automatic reflex that begins when nerves called cough receptors sense that something has entered your airways that shouldn't be there. The force behind a cough occurs because the opening to your windpipe (the glottis), located at the back of your throat, momentarily closes as you exhale. While the glottis is closed, extra pressure builds up in your lungs. Then, when the glottis finally opens, the air explodes out, helping to dislodge particles from your airways. 
There are many reasons for coughing. These include postnasal drip, asthma, GERD, smoking, inhalation of a foreign object, stress, bacterial infections, (pneumonia, pertussis), congestive heart failure, cystic fibrosis, pollution, emphysema, lung cancer, medications, emotional or psychological problems and tuberculosis. 
Coughs Warranting a Doctor Visit
An unexplained chronic cough should be examined by a physician. Sometimes influenza can be followed by a more serious lung ailment like bronchitis or pneumonia. Pulmonary function tests may be performed  or a sputum culture may be analyzed. 
A sputum culture is a test to detect and identify bacteria or fungi (plural of fungus) that are infecting the lungs or breathing passages. Sputum is a thick fluid produced in the lungs and in the airways leading to the lungs. Do not use a mouthwash prior to the test since antibacterial substances may skew lab results. 
Even without a sputum culture by a physician, you may notice signs of more serious illness when clearing your throat by examining the color and texture of phlegm. Color can vary from transparent to shades of yellow, green, brown, and grey depending on the constituents. Phlegm may be a carrier of larvae of intestinal parasites. Bloody sputum can be a symptom of serious disease (such as tuberculosis or pneumonia), but can also be a relatively benign symptom of a minor disease (such as acute bronchitis). In the latter case, sputum may be lightly streaked with blood. Coughing up any significant quantity of blood is always a serious medical condition. Any person who experiences this should seek medical attention. 
Frothy sputum is one of several symptoms that may indicate heart failure, seizures, hypertensive heart disease, pulmonary edema, near drowning, acute mountain sickness or a rare but potentially deadly infection called (Bubonic, Pneumonic or Septicemic) plague (generally spread from rodents to humans).  When accompanied by choking, gagging, unusual pain, or abnormal heart rhythms, seek emergency care.
Pulmonary edema is usually caused by heart failure. Pressure in the veins going through the lungs starts to rise, forcing fluid into the alveoli. This interrupts normal oxygen movement through the lungs and manifests pink frothy sputum. Diagnosis is confirmed on X-ray of the lungs, which shows increased fluid in the alveolar walls. [7,8]
Regardless of the cause, you will feel better if your lungs are clear of phlegm. Stay hydrated  and get plenty of rest to boost your immune system.
- Cough Causes, Symptoms, Treatment. PDRhealth.com
- Lung Function Tests. WebMD.com
- Routine sputum culture. MedlinePlus, nih.gov
- Sputum Culture. cigna.com
- Phlegm. Wikipedia.org
- Is it possible that non-productive cough turns to productive cough?. mucosolvan.com
- Frothy sputum. healthline.com
- Pulmonary edema. Wikipedia.org
- Chest Cold Remedy to Lossen Phlegm. eHow.com
- Sneezing. formulamedical.com
- New Technique May Help Diagnose Asthma, COPD. WebMD.com