Causes of a nighttime cough can vary from minor infections like a cold to more serious problems like asthma. A nighttime cough lasting more than 4 weeks is considered chronic and should be evaluated by a doctor. Keeping a cough journal, including frequency, duration, timing and any associated triggers, may be helpful for monitoring a nocturnal cough and aid the doctor in determining if treatment is necessary.
Postnasal Drip Syndrome
Postnasal drip occurs when the nose produces excessive amounts of mucus. The mucus may drip out the nose during the day, but when the child lies down at night, mucus collects in the back of the throat, triggering a cough. Postnasal drip syndrome is a common cause of nighttime coughing in children. Common causes include breathing cold or dry air, infections like a cold or the flu, allergies and nonallergic rhinitis -- irritated nasal passages typically caused by exposure to environmental irritants such as smoke, pollution or solvents such as cleaning solutions.
Nocturnal asthma is another common cause of nighttime coughing in children. Coughing occurs at night primarily because of changes in the airways that occur with sleep. An asthmatic cough tends to be a dry, hacking cough and is frequently accompanied by wheezing. A January 2009 review article in the "McGill Journal of Medicine" noted that nocturnal asthma may be triggered by allergens or other environmental agents. Discuss any signs or symptoms of asthma with your child's doctor, and develop and follow an asthma management plan as appropriate.
Gastroesophageal Reflux Disease
Gastroesophageal reflux disease, or GERD, occurs when acid from the stomach leaks upward into the esophagus. Stomach acid irritates the throat and may cause a cough, which is generally dry. Some children and adults with GERD experience symptoms primarily at night, because stomach contents can flow into the esophagus more easily while lying down. According to a May 2013 report in "Pediatrics," some amount of acid reflux occurs in approximately 50 percent of 4-month-olds, but prevalence drops to 5 to 10 percent by age 1. Obesity, nervous system disorders and hiatal hernia -- an abnormal opening in the muscular sheet that separates the chest and abdominal cavities -- increase the risk of GERD in children.
When to Seek Medical Attention
Other symptoms occurring with a nighttime cough should be discussed with your child's doctor, including fever, a whooping or whistling sound associated with breathing, coughing up blood, chest pain, listlessness or crankiness. Any cough that persists for more than a few hours in an infant younger than 4 months or more than 3 weeks in an older child should be evaluated by your child's doctor. If in doubt, call the doctor. Seek medical attention immediately if your child is working hard to breathe, has trouble speaking due to shortness of breath or has a blue or dusky color to his lips, face or tongue.