Croup vs bronchiolitis: telling the two childhood chest illnesses apart

Both illnesses are usually caused by viruses that cause cold-like symptoms first, and both can make a parent frightened because the child's breathing sounds different. They are, however, different conditions affecting different parts of the airway. Croup involves the voice box and windpipe, which is why it brings a barking cough, a hoarse voice and a harsh noise on breathing in. Bronchiolitis is an infection of the smallest airways in the chest, which is why it brings fast breathing, wheezing or crackling and trouble feeding.

The NHS stresses that croup is usually mild but is worth a call to NHS 111 or a GP because treatment may help. Bronchiolitis is also usually mild, and there is no specific treatment, but it can be serious in some children.

The NHS describes croup as a common condition that mainly affects babies' and young children's airways. Symptoms are a barking cough, a hoarse voice, difficulty breathing and a high pitched, rasping sound when breathing in. Children usually have cold-like symptoms to begin with, such as a temperature, runny nose and cough, and the croup symptoms come on after a few days and are often worse at night.

If a doctor confirms mild croup, the NHS says it usually gets better on its own within 48 hours. At home it advises sitting the child upright, keeping them calm because crying can make symptoms worse, giving plenty of fluids, checking on them regularly including at night, and giving paracetamol or ibuprofen for a high temperature or discomfort. It specifically says not to put a child in a steamy room or get them to inhale steam.

The NHS describes bronchiolitis as a common chest infection that affects babies and children under 2. It begins with cold-like symptoms such as sneezing, a runny or blocked nose and a slightly high temperature. A child may then develop a cough, breathe more quickly, find it difficult to feed or eat, have noisy breathing (wheezing or crackling sounds) and become irritable. Symptoms are usually worst between days 3 and 5, and the cough usually gets better in 3 weeks.

It is usually caused by a viral infection, most often respiratory syncytial virus (RSV), which the NHS says almost all children get at least once before they are 2. Babies under 6 months, those born prematurely, and those with a weakened immune system or long-term lung or heart conditions are at higher risk of becoming seriously ill. The NHS also notes that bronchiolitis is different from bronchitis.

For croup, the NHS advises asking for an urgent GP appointment or calling NHS 111 if you think your child may have croup, because a doctor may give medicine to shorten the illness, and again if your child is getting worse or not getting better after seeing a GP. Occasionally a child is referred to hospital if more seriously ill or under 3 months old.

For bronchiolitis, it advises an urgent GP appointment or NHS 111 if a cold is getting worse, the child is feeding or eating much less than normal, has had a dry nappy for 12 hours or more or shows other signs of dehydration, is under 3 months with a temperature of 38C or older than 3 months with 39C or higher, or is very tired, irritable or not themselves. It also says parents who are worried should trust their own judgement.

Call 999 or go to A&E for either illness if the child is struggling to breathe (grunting, tummy sucking under the ribs), has pauses in breathing, has blue, grey, pale or blotchy skin, lips or tongue, or is floppy and will not wake up or stay awake. The NHS adds that you should not drive to A&E yourself but ask someone else to drive or call 999.

For bronchiolitis the NHS recommends handwashing, cleaning toys and surfaces, avoiding sharing cups and cutlery, using disposable tissues, and keeping newborn babies away from anyone with a cold or flu. It also says not to smoke around your child, because breathing in cigarette smoke raises the risk of severe bronchiolitis.

The RSV vaccine is available on the NHS from 28 weeks of pregnancy and helps reduce the risk of severe RSV in the baby for the first 6 months after birth. Some higher-risk children may be given antibody injections each winter. No equivalent vaccine for croup is described on the NHS page, although it lists other illnesses that can look similar, including the common cold and whooping cough.