The world’s growing allergy problem, how to find out if you have one and what do if it’s a food allergy

Allergies affect up to 40 per cent of the world’s population, according to the World Health Organisation, and the proportion of sufferers in big cities and industrialised countries is rising. They can cause chronic illness and, in the case of some food allergies, can be fatal.

More than one in two people in Hong Kong suffer from one or more allergic diseases, according to the Hong Kong Institute of Allergy, which will hold events to raise public awareness about allergies to mark World Allergy Week that begins today.

Children born in Hong Kong have an elevated risk of developing allergies, for two reasons. Babies delivered by caesarean section are five times more likely to suffer from common allergies than those born by vaginal delivery, according to Dr Lee Tak-hong, director of the Allergy Centre at Hong Kong Sanatorium & Hospital in Happy Valley. Hong Kong has one of the highest rates of birth by caesarean section in the world, with more than four in 10 babies born by C-section, double the proportion in the developed world. Secondly, says Lee, the risk of allergies is four times higher in infants fed with cow’s milk formula than breastfed children. “Breastfeeding for a minimum of six months is the best prevention strategy,” he says. Yet in Hong Kong only 2.3 per cent of mothers exclusively breastfed their baby for six months, according to a 2013 survey of babies born in 2012 by the Department of Health.

Around 5 per cent of Hong Kong children aged under 14 have food allergies, according to the Allergy Alliance, and nearly one in six of these are estimated to be at risk of going into anaphylactic shock – a severe, potentially life-threatening allergic reaction – if they eat something to which they are allergic.