There are a number of reasons for dry cough, ranging from the early signs of a respiratory infection to a cancerous growth in the lungs. Persistent dry coughs should be treated by a doctor, because they can determine the cause and recommend a treatment. Failure to receive treatment for a dry cough can allow an underlying problem to become quite severe.
Some people experience dry coughs in the early stages of a respiratory or viral infection, or when an infection is on the wane. When such infections are at their peak, the cough usually becomes productive, with coughs bringing up sputum, in contrast with a true dry cough, which tends to feel dry and rasping. People with chronic infections can develop very severe dry coughs which may leave the throat feeling very tender.