Recurrent croup: why it keeps coming back and what to do

Croup is an infection of the voice box (larynx) and windpipe (trachea). Patient.info explains that these are the upper and lower parts of the breathing tube that connects the mouth to the top of the lungs, and that the usual cause is a viral infection. The inflammation and swelling of the vocal cords produces the typical harsh, barking cough, and narrowing of the airway can produce a noisy sound on breathing in called stridor.

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. It says children usually have cold-like symptoms first, such as a temperature, runny nose and cough, and that croup symptoms come on after a few days and are often worse at night.

There is no single explanation. Patient.info notes that croup is common in children aged 6 months to 3 years and that some children have two or more bouts during childhood. Croup is caused by common viruses, and a child can catch a different virus, or the same type again, on another occasion, so repeated episodes in a small child do not by themselves mean something is wrong.

The same source explains why croup mostly affects the youngest: in older children the breathing tube becomes wider and stronger, so the viruses that cause croup in toddlers usually produce only a cough or sore throat. Croup is uncommon after 6 years of age. Patient.info also notes that croup often occurs in outbreaks in winter.

The sources read for this page do not give figures for how often croup recurs or list all the possible reasons. Where a child has many episodes, episodes that start with no cold at all, noisy breathing between episodes or symptoms that start very young, it is reasonable to ask a GP or paediatrician whether anything else, such as another cause of airway narrowing, needs to be considered. A clinician will decide that after hearing the history and examining your child.

Most children have mild croup: a barking cough with cold symptoms and little difficulty breathing. Patient.info says parents can expect one or two disturbed nights, that about 1 in 10 children with croup are admitted to hospital for observation, and that most children admitted go home within 24 hours.

The concern is severe narrowing of the breathing tube. Patient.info advises seeing a doctor quickly if breathing symptoms get worse, with signs such as rapid breathing, more effort to breathe (the chest or neck muscles being pulled in with each breath), restlessness or agitation, or unusual paleness, or if a high temperature lasts longer than five days.

• Call 999 or go to A&E if your child is struggling to breathe, with grunting, tummy sucking in under the ribs or breathing that sounds different (NHS).

• Call 999 or go to A&E for blue, grey, pale or blotchy skin, lips or tongue (NHS).

• Call 999 or go to A&E if your child is sleepier than normal, hard to wake, unusually quiet and still, or limp and floppy (NHS).

• Call 999 or go to A&E if your child is drooling more than normal, finding it hard to swallow or wants to sit rather than lie down (NHS).

• Do not drive to A&E yourself with a child in this state; the NHS says to ask someone to drive or call 999.

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. At home, it suggests sitting your child upright, comforting them and 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 says not to put a child in a steamy room or let them inhale steam; Patient.info adds that there is little evidence steam helps and that some children have been scalded.

Patient.info says a steroid such as dexamethasone is usually prescribed, that a single dose often eases symptoms within a few hours, and that steroids do not shorten the illness but are likely to reduce the severity of breathing symptoms. Inhaled adrenaline is sometimes used in hospital for moderate or severe breathing difficulty and improves symptoms after about 30 minutes, although the benefit fades after about two hours. Cough medicines are not helpful and are not suitable under 6 years.

Patient.info also warns against trying to look into your own child's throat, because very rarely the symptoms are caused by epiglottitis, in which looking in the throat can cause further swelling.

Patient.info says symptoms usually peak after one to three days and a mild, irritating cough may last about another week. Between episodes children are usually completely well. Keeping a short note of the date, the time of day, whether there was a cold beforehand and what treatment was given can help a GP see a pattern if episodes keep happening.

Because croup can start suddenly at night, many families find it helpful to know the emergency signs in advance and to have paracetamol or ibuprofen suitable for the child's age at home. Always follow the instructions on the packaging or a pharmacist's advice for dose and age.

Croup is assessed through GP practices, NHS 111, urgent treatment centres and emergency departments. A child with repeated or unusual episodes may be referred to a paediatrician, and sometimes to an ear, nose and throat specialist, who can decide whether any further investigation of the airway is needed. Private paediatric and ENT assessment is available in the UK, but the first step, particularly for a child with breathing difficulty, is the same: prompt NHS assessment.