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Bronchiolitis in babies: what parents need to know
Bronchiolitis is a common chest infection in babies that starts like a cold and can make breathing harder.
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What it is
Bronchiolitis is an inflammation of the small airways in the lungs [6][7]. It is the most common cause of this kind of illness in children under 1 year of age [6]. It is usually caused by respiratory syncytial virus (RSV) [6]. Most of the time RSV causes a mild, cold-like illness, but it can also cause bronchiolitis or pneumonia [7].
The early symptoms are similar to a cold: sneezing, a runny or blocked nose and a slightly high temperature [1]. Your child may then get other symptoms, such as a cough, breathing more quickly, finding it difficult to feed or eat, noisy breathing (wheezing or crackling sounds) and becoming irritable [1]. Symptoms are usually worst between days 3 and 5, and the cough usually gets better in 3 weeks [1]. RSV may not be severe when it first starts, but it can become more severe a few days into the illness [9].
Some babies are more at risk of becoming very sick. This includes infants younger than 6 months of age [6]. Two to three out of every 100 infants under 3 months are hospitalised with RSV every year [7]. In the most severe cases, a child may need extra oxygen, fluids given into a vein if they cannot drink enough, or a breathing tube with a machine to help them breathe [6][7]. In most of these cases, hospitalisation lasts only a few days [6][7].
There is a vaccine that helps reduce the risk of RSV causing problems such as bronchiolitis [4]. According to the NHS, it is offered from 28 weeks of pregnancy, which helps protect your baby for the first 6 months after they are born [4].
What you can do at home
- Offer your child plenty to drink, and keep feeding them little and often if they are finding feeds hard [1].
- Watch how many wet nappies they have, so you notice signs of dehydration early [1].
- Check their temperature if you have a digital thermometer [8].
- If you do not have a thermometer, look for signs such as their back or chest feeling hotter than usual, sweatiness and shivering [8].
- Keep checking on them, especially at night, because symptoms can get worse a few days into the illness [9].
- Trust your own judgement as a parent — you may know if your child seems seriously unwell [1][8].
Antibiotics do not work for viral infections, so they will not relieve the symptoms or speed up recovery [10].
When to see a doctor or go to the emergency department
Call your local emergency number if:
- your child is having difficulty breathing — you may notice grunting noises, their tummy sucking under their ribs, or they may be breathing quickly [1]
- there are pauses when your child breathes [1]
- your child’s skin, tongue or lips are blue or grey — on brown or black skin, this may be easier to see on the palms of the hands, soles of the feet, lips, gums and inside the eyelids [1]
- your child is floppy and will not wake up or stay awake [1]
- your child is under 5 years old and has a temperature below 36C [8]
Ask your doctor for urgent advice if:
- your child has had a cold and it is getting worse [1]
- your child is feeding or eating much less than normal [1]
- your child has had a dry nappy for 12 hours or more, or shows other signs of dehydration [1]
- your baby is under 3 months and has a temperature of 38C, or is older than 3 months and has a temperature of 39C or higher [1]
- your baby feels hotter than usual when you touch their back or chest, or feels sweaty [1]
- your child has a very high or low temperature, feels hot or cold to the touch, or is shivering [1]
- your child is very tired, irritable or does not seem themselves [1]
- you are worried about your child [1]
Common questions
How long will it last? Symptoms are usually worst between days 3 and 5, and the cough usually gets better in 3 weeks [1].
Is it the same as croup? No. Croup causes a barking cough that may sound like a seal, a hoarse voice and a high-pitched, rasping sound when breathing in [2]. Bronchiolitis causes cold-like symptoms with wheezing, rapid breathing and not feeding well [2].
Can it be prevented? The RSV vaccine helps reduce the risk of RSV causing problems such as bronchiolitis [4]. According to the NHS, it is available from 28 weeks of pregnancy and helps protect your baby for the first 6 months after birth [4].
Could it affect my child later? According to the NHS, having illnesses as a child that affected breathing, such as bronchiolitis or croup, may make asthma more likely [5].
Sources
[1] NHS — “Bronchiolitis” (2026), section “Symptoms of bronchiolitis”, p. 1 — https://www.nhs.uk/conditions/bronchiolitis/ [2] NHS — “Croup” (2025), section “Symptoms of croup”, p. 1 — https://www.nhs.uk/conditions/croup/ [4] NHS — “Bronchiolitis” (2026), section “RSV vaccination”, p. 1 — https://www.nhs.uk/conditions/bronchiolitis/ [5] NHS — “Asthma” (2024), section “Causes of asthma”, p. 1 — https://www.nhs.uk/conditions/asthma/ [6] CDC — “About RSV”, section “RSV can be dangerous for infants and older adults”, p. 1 — https://www.cdc.gov/rsv/about/index.html [7] CDC — “RSV in Infants and Young Children”, section “Severe RSV illness”, p. 1 — https://www.cdc.gov/rsv/infants-young-children/index.html [8] NHS — “Respiratory syncytial virus (RSV)” (2024), section “How to take a temperature”, p. 1 — https://www.nhs.uk/conditions/respiratory-syncytial-virus-rsv/ [9] CDC — “RSV in Infants and Young Children”, section “Did you know? Symptoms in infants and young children”, p. 1 — https://www.cdc.gov/rsv/infants-young-children/index.html [10] NHS — “Flu” (2026), section “Antibiotics”, p. 1 — https://www.nhs.uk/conditions/flu/
This guide summarises published paediatric guidelines. It is not medical advice and does not replace your paediatrician. In an emergency, call your local emergency number.
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