People who have a post nasal drip cough should realize their condition is now being called upper airway cough syndrome (UACS). This is a situation where a person has a cough for a long period of time with nasal congestion. It is often caused by mucus dripping down the back of their throat. This causes a person to have a regular sensation they must clear their throat. UACS can cause a person to have a hoarse voice as well as wake up in the morning with something noticeable in the back of their throat. UACS can result from a person having an allergic or a nonallergic reaction to something in their environment. It could also be the result of sinusitis.