Green or Dark Yellow Phlegm. A thick and dark yellow phlegm may be a sign of a viral or bacterial infection, sinus infection, or lower respiratory tract infection. Typically, this occurs when the immune system sends white blood cells, known as neutrophils, to the area of infection.
Also to know is, how long should you have a chesty cough for?
A "dry cough" means it's tickly and doesn't produce any phlegm (thick mucus). A "chesty cough" means phlegm is produced to help clear your airways. Most coughs clear up within three weeks and don't require any treatment. For more persistent coughs, it's a good idea to see your GP so they can investigate the cause.
Why do I have this cough that won t go away?
One is a postnasal drip or mucus cough, in which your body's attack on the cold virus collects in your throat, triggering your cough. But they won't make it go away completely — or kill the virus that led to it. The second kind of post-cold cough is called post-inflammatory bronchospasm, and it resembles asthma.
What does a persistent cough mean?
A persistent cough is defined as a cough that persists for a period of eight weeks or longer. The cough may be dry or productive, in other words, you may or many not cough up mucus (sputum). An "acute" cough, in contrast, refers to a cough that lasts less than eight weeks, such as those that occur with the common cold.