SKY NEWS: 15-year-old's allergy death 'brought everything flooding back'

Description

"We don't know why any of the allergies are increasing, food allergies or asthma or hay fever" says Professor Sheena Cruickshank from Manchester University.

"One idea is we are becoming cleaner and our immune system isn't getting educated any more.

"Another idea is that we don't get the same sort of infections as we used to, or the microbes that we are breathing in have changed, or the microbes that live inside us have changed and they don't train up our immune system properly so it can go wrong."