Chronic Cough with Uncertain Cause (Child)

Child's head and torso showing upper and lower respiratory tracts and upper digestive system.

Coughs are one of the most common symptoms of childhood illness. They most often occur as part of the common cold, flu, or bronchitis. This kind of cough usually gets better in 2 to 3 weeks. A cough that persists longer than 3 to 4 weeks may be due to other causes.

If the cough does not improve over the next 2 weeks, further testing may be needed. Follow up with the healthcare provider as directed. Based on the exam today, the exact cause of your child’s cough is not certain. Below are some common causes for persistent cough.

Postnasal drip

A cough that is worse at night may be due to postnasal drip. Excess mucus in the nose drains from the back of the nose to the throat and triggers the cough reflex. If postnasal drip has been present more than 3 weeks, it may be due to a sinus infection or allergy. Common allergens include dust, smoke, pollen, mold, pets, cleaning agents, room deodorizers, and chemical fumes. Over-the-counter antihistamines or decongestants may be helpful for allergies, but don't use these in children younger than 6 years of age. A sinus infection may require antibiotic treatment. See your healthcare provider if symptoms continue.


A cough may be the only sign of mild asthma. Your child’s healthcare provider may do tests to find out if asthma is causing the cough. Your child may also take asthma medicine on a trial basis.

Foreign object

Infants and young children who put small objects in their mouth can inhale them into the lungs. This may cause an initial severe coughing spell that becomes a chronic cough. Slight wheezing or shortness of breath may be present. This is a serious problem. If this is suspected, it must be checked by the healthcare provider.

Acid reflux (heartburn, GERD)

The esophagus is the tube that carries food from the mouth to the stomach. A valve at its lower end prevents the backward flow of stomach contents (reflux). When the valve does not work correctly, food and stomach acid flow back into the esophagus. (This is also called gastroesophageal reflux disease, or GERD). When this flows as far as the mouth, it looks like “spitup.” This is not vomiting. It happens without any sign of retching. Signs of reflux in infants usually occur soon after eating. These signs include spitting up, vomiting, poor weight gain, fast or difficult breathing, and unusual fussiness or irritability. In older children, signs of reflux may include belching, vomiting, heartburn, stomach pain, acid or bitter taste in the mouth, and painful swallowing. See the healthcare provider for further testing if these symptoms are present.


Strong coughing spells can cause gagging and vomiting during or right after the cough. When a cold is the cause of the cough, lots of mucus may be swallowed. This can cause nausea and vomiting. If repeated vomiting occurs, contact the healthcare provider.

Secondhand smoke

Young children who are exposed to tobacco smoke in their homes can have a chronic cough, as well as any of these symptoms:

  • Stuffy nose, sore throat, or hoarseness

  • Eye irritation, headache, or dizziness

  • Fussiness, loss of appetite, or lack of energy

Infants and children younger than 2 years who are exposed to cigarette smoke have a higher risk of these conditions:

  • Ear and sinus infections and hearing problems

  • Colds, bronchitis, and pneumonia

  • Croup, influenza, bronchiolitis, and asthma

In children who already have asthma, secondhand smoke increases the number and severity of asthma attacks. Secondhand smoke is a serious health risk for your child. You must do what you can to eliminate the exposure.

Follow-up care

Follow up with your child’s healthcare provider, or as advised, if your child’s cough does not improve. Further testing may be needed.

Note: If an X-ray was taken, a specialist will review it. You will be notified of any new findings that may affect your child’s care.

When to seek medical advice

For a usually healthy child, call your child's healthcare provider right away if any of these occur:

  • Fever (see Fever and children, below)

  • Whooping sound when breathing in after a long coughing spell

  • Coughing up dark-colored sputum (mucus)

  • Noisy breathing

Call 911

Call 911 if any of these occur:

  • Coughing up blood

  • Wheezing or difficulty breathing

  • Fast breathing:

    • Birth to 6 weeks, over 60 breaths per minute

    • 6 weeks to 2 years, over 45 breaths/minute

    • 3 to 6 years, over 35 breaths/minute

    • 7 to 10 years, over 30 breaths/minute

    • Older than 10 years, over 25 breaths/minute


Fever and children

Always use a digital thermometer to check your child’s temperature. Never use a mercury thermometer.

For infants and toddlers, be sure to use a rectal thermometer correctly. A rectal thermometer may accidentally poke a hole in (perforate) the rectum. It may also pass on germs from the stool. Always follow the product maker’s directions for proper use. If you don’t feel comfortable taking a rectal temperature, use another method. When you talk to your child’s healthcare provider, tell him or her which method you used to take your child’s temperature.

Here are guidelines for fever temperature. Ear temperatures aren’t accurate before 6 months of age. Don’t take an oral temperature until your child is at least 4 years old.

Infant under 3 months old:

  • Ask your child’s healthcare provider how you should take the temperature.

  • Rectal or forehead (temporal artery) temperature of 100.4°F (38°C) or higher, or as directed by the provider

  • Armpit temperature of 99°F (37.2°C) or higher, or as directed by the provider

Child age 3 to 36 months:

  • Rectal, forehead (temporal artery), or ear temperature of 102°F (38.9°C) or higher, or as directed by the provider

  • Armpit temperature of 101°F (38.3°C) or higher, or as directed by the provider

Child of any age:

  • Repeated temperature of 104°F (40°C) or higher, or as directed by the provider

  • Fever that lasts more than 24 hours in a child under 2 years old. Or a fever that lasts for 3 days in a child 2 years or older.

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