Coughing in Infants: Causes and When to Worry

Why babies cough

Coughing clears mucus and irritants from the airways. Babies have narrow airways, breathe mainly through the nose, and catch frequent colds, so a cough is common. A healthy infant may have 6 to 8 colds a year, especially with older siblings or in daycare. The cough often outlasts the runny nose.

What matters most is not the cough itself but how the baby is breathing, feeding and behaving.

What baby cough sounds can mean

Common causes of cough in infants

Colds

Colds cause a runny or blocked nose, sneezing, mild fever and a cough from mucus dripping down the throat. Babies often sound "rattly" because mucus moves in the nose and throat. Symptoms peak around days 2 to 3, and the cough can last 2 to 3 weeks.

Bronchiolitis

Bronchiolitis is a viral infection of the smallest airways, most often caused by RSV. It is the most common reason babies under 1 are admitted to hospital. It starts like a cold, then over 2 to 3 days the cough worsens, breathing becomes fast and effortful, and wheezing or crackles develop. Most babies recover at home within 2 to 3 weeks, but premature babies, those under 3 months, and babies with heart or lung disease are at higher risk.

Croup

Croup is a viral infection that swells the voice box and windpipe. It is most common from 6 months to 3 years. It causes a barking cough, a hoarse voice and sometimes a rasping sound when breathing in (stridor), often worst at night. Most cases are mild and last 2 to 3 days.

Whooping cough (pertussis)

Whooping cough is a bacterial infection that is most dangerous in babies under 6 months. It starts like a cold, then after 1 to 2 weeks causes bursts of coughing that leave the baby exhausted, red-faced or blue. Young infants may not whoop at all and may simply have pauses in breathing. It needs urgent medical care and antibiotics.

Reflux

Many babies spit up. When stomach contents reach the throat, they can cause coughing, especially during or after feeds or when lying flat. It usually improves by 12 to 18 months.

Other causes

• Pneumonia: fever, fast breathing and a worsening cough
• Asthma: repeated wheezy episodes with colds, more often diagnosed after age 2
• Smoke exposure: secondhand smoke irritates airways and makes coughs and infections more frequent
• Rare causes: cystic fibrosis, congenital airway problems and immune disorders, suggested by a persistent cough with poor weight gain or repeated chest infections

When to worry about a baby's cough

Watch your baby's breathing with the clothes off the chest. Signs of breathing difficulty include:

• the skin pulling in between or under the ribs, or above the breastbone
• flaring nostrils
• grunting with each breath
• head bobbing
• breathing so fast the baby cannot feed
• pauses in breathing of 10 seconds or more

Babies under 3 months need medical assessment for any fever. Also seek care if your baby is feeding much less, has fewer wet diapers, is unusually sleepy, or you feel something is wrong.

How doctors assess a coughing baby

A doctor will count the breathing rate, watch for signs of effort, listen to the chest and measure oxygen levels with a small clip on the foot or finger. Tests are usually not needed for colds or bronchiolitis. A chest X-ray may be done if pneumonia or an inhaled object is suspected, and a nose swab or blood test can confirm whooping cough.

Home care for an infant cough

• Clear the nose: use saline drops and a bulb syringe or nasal aspirator before feeds and sleep. Babies breathe mainly through the nose.
• Feed little and often: smaller, more frequent breast or bottle feeds are easier for a congested baby.
• Keep them upright when awake and after feeds. Always put a baby to sleep flat on their back, without pillows or wedges.
• Cool-mist humidifier: may help ease a congested nose. Keep it clean and out of reach. Never use steam or hot water.
• Fever relief: acetaminophen (paracetamol) can be used from 2 to 3 months if the baby is uncomfortable, and ibuprofen from 6 months, at the dose for the baby's weight. Ask a doctor first for babies under 3 months. Never give aspirin.
• Keep the home smoke-free.

Prevention

• Whooping cough vaccine (Tdap) in pregnancy, ideally at 27 to 36 weeks, passes protection to the baby. Babies start their own DTaP vaccine at 2 months.
• RSV protection: a maternal RSV vaccine in late pregnancy or an RSV antibody injection for the baby protects against severe bronchiolitis in the first RSV season.
• Flu vaccine for everyone in the household, and for babies from 6 months.
• Wash hands before handling the baby, and keep sick visitors away.
• Breastfeeding reduces the risk and severity of respiratory infections.

Frequently asked questions

When should I worry about my baby's cough?

Get urgent help if your baby is struggling to breathe, has pauses in breathing, turns blue or gray, is very sleepy, or is under 3 months with a temperature of 38 °C (100.4 °F) or higher. See a doctor if feeding drops, coughing fits occur, or the cough lasts more than 3 weeks.

How long does a cough last in a baby?

A cough from a cold usually lasts 1 to 3 weeks. Bronchiolitis coughs can last up to 3 to 4 weeks. Whooping cough can last up to 10 weeks. A cough that persists beyond 3 to 4 weeks should be checked.

What does a whooping cough sound like in a baby?

Older children make a "whoop" sound when breathing in after a coughing fit. Young babies often do not whoop. Instead they have bursts of coughing, gag, turn red or blue, or briefly stop breathing. Any of these needs urgent medical care.

Is a wet cough or a dry cough worse in a baby?

Neither is automatically worse. A wet cough is common with colds and bronchiolitis. A barking dry cough suggests croup. How hard your baby is working to breathe, and how well they feed, matter more than the type of cough.

Can I give my baby cough medicine?

No. Over-the-counter cough and cold medicines are not safe for infants and do not work in young children. Use saline drops, nasal suction, fluids and comfort instead. Never give honey to babies under 12 months.

Can teething cause a cough?

Teething can cause extra drool that sometimes triggers a mild cough, but it does not cause fever above 38 °C (100.4 °F), wheezing or breathing difficulty. If those are present, look for another cause.