Croup in children: the barking cough, what helps and when to get help

Croup describes swelling of the voice box (larynx) and the windpipe (trachea) caused by a viral infection. In a small child the airway is narrow to begin with, so even a modest amount of swelling changes the sound of breathing. That is why a child who seemed to have a simple cold can suddenly produce a loud, seal-like cough in the evening.

NHS inform describes croup as affecting mainly children aged 6 months to 3 years, with most cases in one-year-olds, slightly more boys than girls, and a seasonal peak in late autumn and early winter. A child can have croup more than once. NICE CKS adds that children often have a runny nose, cough and fever for somewhere between 12 and 72 hours before the barking cough begins.

The NHS lists a barking cough that may sound like a seal, a hoarse voice, difficulty breathing and a high-pitched, rasping sound when breathing in. That rasping noise is called stridor. NHS inform notes it is often most noticeable when the child cries or coughs, and that symptoms are usually worse at night.

Doctors use a simple grading that parents can borrow when describing their child on the phone. NICE CKS divides croup into four levels, shown below.

NHS inform says several viruses can cause croup but in most cases it is the parainfluenza virus. It spreads through close contact, contaminated objects and surfaces, and droplets from coughs and sneezes. Other viruses on its list include influenza A and B, the cold virus rhinovirus, enteroviruses, RSV and, in children who are not immunised, measles.

Less commonly the same sounds come from something other than infection. NHS inform lists a small object breathed in, such as a peanut or pen cap, inflammation of the epiglottis, a severe allergic reaction, breathing in irritants and acid reflux. This is one reason a sudden noisy-breathing episode in a child who was not unwell beforehand deserves a call to NHS 111 or an urgent medical opinion.

The NHS says to call 111 or ask for an urgent GP appointment if you think your child may have croup, because a doctor may give medicine to shorten the illness, and again if they are getting worse or not improving after seeing a GP. Children under 3 months or those who are more seriously ill may be referred to hospital.

The NHS says to call 999 or go to A&E if your child:

• is struggling to breathe, for example grunting, or the tummy sucking in under the ribcage

• has blue, grey, pale or blotchy skin, lips or tongue (on brown or black skin look at palms or soles)

• is sleepier than normal or difficult to wake, or is unusually quiet and still

• is limp, floppy or not responding as they normally do

• is very upset or restless, has difficulty breathing and cannot be calmed

• is unwell and drooling more than usual, finding it hard to swallow, or wants to sit rather than lie down

For mild croup the NHS advice is to sit the child upright rather than letting them lie down, comfort them because crying can make symptoms worse, give plenty of fluids, check on them regularly including at night, and use paracetamol or ibuprofen for a high temperature or discomfort. NHS inform adds that children under 16 should not be given aspirin, and that cough medicines and decongestants do not ease croup and often cause drowsiness, which can be dangerous when breathing is difficult.

NHS inform says a child is usually prescribed a single dose of an oral corticosteroid, dexamethasone or prednisolone, to reduce the swelling, and lists restlessness, vomiting, upset stomach and headache as possible side effects. NICE CKS recommends a single oral dexamethasone dose for all children with croup, with nebulised budesonide or an injection as alternatives if the child is too unwell to take medicine by mouth. Dosing is calculated by the prescriber from the child's weight and should not be improvised at home.

In severe croup, NHS inform says hospital treatment may include adrenaline or oxygen. NICE CKS says children with moderate or severe croup, or signs of impending respiratory failure, should be admitted, and that admission may also be needed for a child with chronic lung disease, congenital heart disease or a weakened immune system, a breathing rate above 60 a minute, high fever or poor fluid intake.

NHS inform says a GP can usually diagnose croup from the child's symptoms, in particular the sound of the cough. It suggests recording the noise on a phone if the child is only noisy at night. The GP may check temperature, ask about a recent cold, and use a pulse oximeter (a clip on the finger or earlobe) to measure oxygen levels. No scan or blood test is usually needed for typical croup.

NHS inform also warns parents not to look into the child's throat themselves, because this could trigger a spasm of the airway and make breathing harder.

Croup has no specific entry in the UKHSA exclusion list for settings, but the same guidance says that children with respiratory infections should stay away if they have more than mild symptoms, for example a high temperature. In practice a child who is breathing comfortably, drinking and free of fever can usually be judged by the carers and the family together. Because the cough can be loud and may last for days, it is worth telling the setting what the doctor said.

Expect night-time to be the harder part: NHS inform notes that symptoms are often worse at night, so a child may need extra settling and a parent nearby for a few evenings.