Hello  A chronic cough that occurs only at night can be due to a variety of causes. In some cases, underlying allergies or exposure to respiratory irritants such as cigarette smoke or indoor chemicals can cause a cough at night. The cough may subside during the day when you re out of the house and away from the source of irritation.   Here are some other causes of a cough at night you may want to be aware of.  Undiagnosed asthma When most people think of asthma, they think of shortness of breath and wheezing. While asthma may present in this manner, it s not uncommon for the only symptom to be a nagging night time cough that just won t go away.  Medications like ACE inhibitors for hypertension  GERD GERD is an abbreviated term for gastroesophageal reflux. This is a fairly common condition where the flap that separates the esophagus from the stomach is weakened, allowing acid to flow back into the esophagus. Although this usually causes symptoms such as heartburn and an acidic taste in the throat, it sometimes presents with a dry cough only at night. Why does this occur? When you re lying down, acid from the stomach can more easily back flow into the esophagus leading to a coughing spell.   Other causes If you ve recently recovered from a viral infection, the cough may be the last symptom to improve and will often make its presence known when you lie down to sleep.  Another cause of a cough only at night is post nasal drainage related to a sinus infection. Consult your doctor and get yourself examined properly for the diagnosis and treatment. Thanks