Lemsip Guide to CoughsA cough is the most common symptom for which we seek medical advice. A Cough – What is it? Annoying as it is, a cough is simply your body's way of trying to protect itself, by getting rid of an irritation. The 'irritation' could be a tickle caused by inflammation of the upper airways or a build up of mucus in the lower airways. Definitions of a CoughCoughs tend to be described as dry and tickly or chesty and mucus-y – and it's easy to tell why. A dry cough is an irritation with a 'dry' sound and that often feels quite tickly in the throat. Meanwhile a chesty or mucus cough comes from deeper within and is trying to loosen and get rid of the mucus or phlegm. Coughs are also classified according to how long they last – an acute cough being one that is relatively short-lived, i.e. up to three weeks, while a chronic, or persistent cough, goes on for longer. The typical case with a cough caused by a common cold is that it starts off dry and tickly before becoming chestier and more mucus-y later on as the cold develops. It's quite useful to try to understand what type of cough you are suffering from at a given time as the treatments work in very different ways.