More than half the children who have been diagnosed with asthma may not actually have the respiratory condition, according to researchers at Utrecht University’s teaching hospital.

The researchers studied the cases of almost 5,000 children aged between six and 18 and found that thousands had been wrongly diagnosed. The main reason is that it is hard to establish asthma in children under the age of six, research Theo Verheij told broadcaster Nos at the weekend.

‘They are recorded as ‘probable diagnoses,’ Verheij said. ‘And that label remains in their files.’

‘We are talking about children with few complaints who disappear from the radar,’ Verheij said. ‘We are not talking about children with a lot of symptoms and who use a lot of medicine.’

The researchers looked at the medical files of 4,920 children, of whom 546 were indicated as asthma sufferers. Of them, 39% were found to have asthma on the basis of a spirometry test or the severity of their symptoms, Nos said.