Stormy summer could spark huge rise in deadly 'thunderstorm asthma' cases It is possible to treat the effects and in some cases offer desensitisation treatment but the best advice is to minimise exposure. Dr Sankaran, who also lectures at the University of East Anglia, is calling for more research to be carried out into thunderstorm asthma attacks. An estimated five million people in the UK - one million of them children - suffer from asthma which is now the most common chronic condition in the West. The alert comes just days after gardeners warned of poisonous caterpillars which cause vomiting and dizziness if their hairs are inhaled could spread to trees around the Olympics potentially bringing misery to millions of spectators. Experts say the oak processionary moths are spreading into new parts of the country and fear the insects could affect the Olympics if oak trees in East London suffer an infestation. At their caterpillar stage they are covered in 63,000 toxic hairs, which can trigger asthma attacks. Airborne hairs can cause painful skin and throat rashes, running eyes, vomiting and dizziness. You can slow them down but we will never find them all. They will always keep increasing.' said Tony Kirkham, head of the arboretum at Kew Gardens. 'We use spray to keep them at bay but even the nest removals at Kew don't totally control oak processionary moths,'