Croup in children: symptoms, is it contagious, treatment and how long it lasts

The NHS lists the symptoms of croup as a barking cough that may sound like a seal, a hoarse voice, difficulty breathing and a high-pitched, rasping sound when breathing in. Your child will usually have cold-like symptoms first, such as a temperature, runny nose and cough. Croup symptoms usually come on after a few days and are often worse at night.

NHS inform says the harsh noise on breathing in is called stridor and is often most noticeable when the child cries or coughs. NICE CKS notes that symptoms increase with agitation, which is why keeping a child calm matters.

Yes. Croup is commonly caused by a virus, and NHS inform says in most cases it is the parainfluenza virus. The virus can be passed on by close contact with infected people, as well as contaminated objects and surfaces, and it is often spread by breathing in droplets from infected coughs or sneezes.

Other viruses can cause croup too, including influenza A and B, rhinovirus (common cold), enteroviruses, respiratory syncytial virus (RSV) and measles in children who have not been immunised.

NHS inform describes croup as a childhood condition that affects the windpipe (trachea), the airways to the lungs (the bronchi) and the voice box (larynx). NICE CKS explains the clinical features result from inflammation and swelling of upper airway structures (larynx, vocal cords and trachea), narrowing the airway just below the vocal cords.

Because a young child's airway is small, even a little swelling makes breathing noisier and harder. NHS inform says croup in adults is rare. The NHS notes that other conditions can look similar:

NHS inform says most cases of croup are mild and can be treated at home. Children are usually prescribed medication to reduce swelling in the throat: a single dose of an oral corticosteroid called dexamethasone or prednisolone. Side effects can include restlessness, vomiting, upset stomach and headache. NICE CKS recommends a single dose of oral dexamethasone for all children with croup, whether mild, moderate or severe.

The NHS says to ask for an urgent GP appointment or call NHS 111 if you think your child may have croup, as the doctor may give medicine to shorten the illness. In severe cases, NHS inform says treatment in hospital may be needed, which might include adrenaline or oxygen.

The NHS says that if 111 or a doctor confirms your child has mild croup, you can help them feel better:

• Sit your child upright and try not to let them lie down.

• Comfort them if they are distressed and try to keep them calm, because crying can make the symptoms worse.

• Give them plenty of fluids.

• Check on them regularly, including at night.

• Give paracetamol or ibuprofen to help ease a high temperature or any discomfort. NHS inform says children under 16 should not be given aspirin.

• Do not put your child in a steamy room or get them to inhale steam: the NHS says this is not recommended.

• Do not use cough medicines or decongestants: NHS inform says they do not help and often have drowsy side effects that can be dangerous when a child has breathing difficulties.

The NHS says croup usually gets better on its own within 48 hours. NICE CKS says symptoms usually resolve within 48 hours, although some episodes may last for up to one week. NHS inform says symptoms usually only last for a few days and are often worse at night, but can occasionally last up to 2 weeks.

You should seek urgent medical advice if your child's symptoms get worse or are not getting better after seeing a GP.

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

• Is struggling to breathe: you may notice grunting noises, see their tummy sucking under their ribcage, or hear their breathing sound different.

• Has blue, grey, pale or blotchy skin, lips or tongue (on brown or black skin this may be easier to see on the palms or soles).

• Is sleepier than normal or difficult to wake.

• Is unusually quiet and still.

• Is limp, floppy or not responding like they normally do.

• Is very upset or restless, having difficulty breathing and cannot be calmed down.

• Is unwell and drooling more than normal, finding it hard to swallow, or wants to sit rather than lie down.

• Do not drive to A&E: ask someone to drive you or call 999.

NHS inform says to contact your GP practice urgently, or call 111 if the practice is closed, if your child is more short of breath than usual, has pain when breathing in or coughing, is confused, dizzy or lightheaded, cannot keep food or fluids down, is coughing up blood, has had a dry nappy for 12 hours or more or shows other signs of dehydration, or has a very high or low temperature.

For a baby under 3 months, NHS inform says to call 999 or go to A&E for a temperature of 38C or above, or 36C or below, if they have not had a vaccination in the past 2 days.

NHS inform says croup can usually be diagnosed by a GP, who checks your child's symptoms, particularly the sound of their cough. If you can, record the noise your child makes on your phone so your GP can hear it, especially if your child only coughs at night.

The GP may check your child's temperature, ask about a recent cold, and do a pulse oximetry test to check oxygen levels with a sensor clipped to an earlobe or finger, which does not hurt. NHS inform advises you not to try to look at your child's throat yourself, as it could trigger a spasm of the airway and make breathing even more difficult.

The NHS says occasionally a child may be referred to hospital if they are more seriously ill or under the age of 3 months. NICE CKS says hospital admission may be required if there is chronic lung disease, congenital heart disease, immunodeficiency, a respiratory rate of over 60 breaths a minute, high fever or inadequate fluid intake, and that children with moderate or severe croup or impending respiratory failure should be admitted.

In the UK, children with suspected croup are usually assessed through NHS 111, a same-day GP appointment or an urgent treatment centre, and those who are more unwell go to A&E. Steroid treatment is part of normal NHS care.

Private paediatric services or out-of-hours clinics may offer a quick assessment, but the same warning signs apply: a child who is struggling to breathe needs emergency care, not an appointment.