Hay fever and asthma sufferers are being warned of 'thunder fever,' which could provoke severe allergy symptoms as temperatures soar.
The Met Office has warned of very high pollen levels across most of England and Wales this week as temperatures rise.
Across many parts of the UK including the Midlands, temperatures are expected to rise to 31C on Friday.
Authorities have been issuing heat health warnings as forecasters warn of baking conditions hotter than Turkey or Jamaica.
People with asthma are being urged to be aware of 'thunder fever', which is caused by the tail end of a tropical storm.
Lyn Kendall explains what it's like to suffer from hayfever.
What is 'thunder fever?'
According to the Met Office, it is not a scientific term.
However it could describe what is know as thunderstorm asthma, which scientists globally are still working to understand, according to the national forecaster.Research is looking at how, in very specific conditions, there’s a chance that thunder and lightning can increase the symptoms of those with hay fever.
"Whether that’s down to airflows or lightning splitting pollen grains open, it’s too early to say, but it’s something that is in active research with our health partners,” the Met Office says.
Hay fever advice:
St Johns Ambulance service has issued advice to the roughly 10 million people who suffer with hay fever in England.
1) It is recommended to start taking hay fever medications a few weeks before the pollen season starts. Use a pollen calendar as a tool to guide you.
2) Speak to your pharmacist for the best advice on treatments, for example, whether to take oral medication or put treatments directly on the eyes or nose.
3) Regular vacuuming and damp-dusting can help keep the levels of pollen down in your home.
4) Some vacuum cleaners come with a HEPA filter that can reduce the levels even more.
5) Putting vaseline around your nostrils can help trap pollen.
6) Wear wrap-around sunglasses, since this can prevent the pollen getting to your eyes and irritating them.
When should I see my GP?
St Johns Ambulance says you should see your GP if your symptoms are not responding to the treatments advised by a pharmacist.
You should also consult your doctor if you're asthmatic and noticing your chest is tight and you have a persistent cough.
A GP may also prescribe other treatments such as a steroid nasal spray. You may be referred to an allergy specialist in some severe cases.
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