A cough can be caused by a variety of things, such as allergies or a lung or throat infection. However, a cough is also a tell-tale sign of the flu. In the earliest stages, the cough may be dry and lack mucous and as it continues, you might notice more phlegm.
The persistent cough that accompanies the flu may be hard to distinguish from a lung infection or bronchitis, except that in the latter case, the coughing feels more involuntary, is stronger and produces phlegm that may have various colors in it.
If you have these symptoms it is important to seek medical help right away. To relieve your cough, plug in a vaporizer at night to make the air less dry, take cough drops or drink tea with honey and lemon. You may try cough medicine, but many traditional medicines may make you drowsy, so take them before you go to bed.