Do distinctions between dry, tickly and chesty coughs have any medical basis?
If I may add to what Resonating has said, when it comes to infections, dry cough is usually associated with a viral infection, whereas wet cough is usually caused by bacteria. The two are treated very differently - dry cough is remedied with cough-supressing drugs (antivirals are rarely needed), whereas bacterial infections are medicated with antibiotics (antivirals are NOT antibiotics) and drugs that help clear the mucus from the respiratory pathway. Treating wet cough with dry cough medications is not only ineffective, it can also be dangerous. One more thing - not all bacterial infections necessitate antibiotics which should be used sparingly because the world is running out of antibiotics.