A dry cough by definition is nonproductive. It is caused by increased sensitivity of airway nerves, and is often the result of irritation (cough = more cough).
How to Treat Dry Coughs:
Treat dry coughs with cough suppressants, such as dextromethorphan, to reduce frequency/intensity.
The Tale Of Two Coughs - Dry Coughs And Chesty Coughs
When it comes to cold and flu symptoms, there are two main types of coughs—chesty coughs and dry coughs.
Dry Coughs
Chesty Coughs
A chesty cough may be productive or nonproductive. It is caused by excess mucus in the airway, or stimulation of airway nerves to induce feelings of pain, pressure, and congestion. It is often accompanied by irritation-induced cough.
How to Treat Chesty Coughs:
Treat chesty coughs with expectorants to speed mucus removal. Also, hydrate the airway to sooth airway nerves. Chesty coughs may or may not be accompanied by expectoration of excess mucus. In general, with uncomplicated upper respiratory tract infections, there is minimal evidence of excess mucus. The suggested treatment for this condition is a mucus-thinning agent such as guaifenesin.