A spike in asthma-related admissions to Norfolk's largest hospital over the weekend could have been caused by the heavy rain, according to an expert.

Dr Prasanna Sankaran, a clinical lecturer at the University of East Anglia and a specialist registrar in respiratory medicine at the N&N, said: 'I have spoken to our asthma specialist nurse and they said admissions have been more than usual, particularly in short stay in A&E.

'It's sometimes difficult to pinpoint exactly what causes it, unless you take specific blood tests, but it's usually after rain and is down to fungal spores.

'Heavy rain and thunderstorms can cause these attacks in people with asthma.

'The fungal spores come up from the soil and it can happen anywhere it's damp.

'It's a very, very under-recognised cause of asthma.'

While thunderstorm-related asthma is not yet fully understood, humidity before the storm must be high enough so that grass pollen or fungal spores are released and survive in the atmosphere.

Wetherquest's Chris Bell said: 'There were widespread thunderstorms over much of Suffolk and the Eastern half of Norfolk on the 25th and on the 26th and 27th there were a few isolated thunderstorms around.

'It's probably more to do with the very heavy rain there was around too.'

Dr Sankaran said there still needed to be more research carried out, but these types of patches could occur particularly in May and June, and all of East Anglia presents problems for asthmatics with pollen from oil seed rape and fungal spores.

He added: 'I know people who live in Norfolk, who have lived elsewhere, and developed asthma after coming to Norfolk, but what strictly causes it is difficult to pinpoint.'

Dr Sankaran said: 'If someone has had a track record of worsening symptoms when it rains and there are thunderstorms then they should avoid going out in the rain and the Met Office also provides guidance on thunderstorms which could cause asthma attacks.'