Pollen, hay fever and asthma

Cut your risk of an asthma attack triggered by pollen

Hay fever and COVID-19
Asthma and tree pollen
Grass and weed pollens
Which pollen is your personal trigger?
Get set for pollen season
Three steps to reduce the risk of hay fever triggering an asthma attack
See your GP if your asthma is getting worse
Hay fever, pollution, hot weather and thunderstorms

Hay fever and COVID-19

If you're allergic to pollen, you might be getting symptoms as tree pollen starts to appear, and these could be confused with COVID-19. The main difference is that hay fever doesn't usually come with a fever (high temperature).

We are urging everyone who suffers from hay fever to make sure they start their regular hay fever medicines, so they reduce the risk of hay fever triggering an asthma attack.

If you have hay fever and get COVID-19, then you could be more at risk of both setting off your asthma symptoms, so we are asking everyone with hay fever and asthma to:

  • make sure you're taking your asthma medicines as prescribed
  • control your hay fever symptoms with your medicines
  • take steps to avoid catching or spreading COVID-19 by staying at home

Asthma and tree pollen

Many people with asthma also have hay fever, and find their asthma symptoms are triggered by pollen.

Tree pollen is a common hay fever trigger. It’s the first pollen to be released during hay fever season, and levels are typically highest from late March to mid-May.

Grass and weed pollen

Around 95% of people’s hay fever is triggered by grass pollen, which tends to be highest between mid-May and July. In fact, there’s strong evidence that when grass pollen levels are high, people with asthma are more likely to need hospital treatment.

Hay fever can also be triggered by weed pollen, which is highest from the end of June until September.

Which pollen is your personal trigger?

You can be allergic to more than one kind of pollen across the year.

To work out which pollen sets off your hay fever, note the days when your symptoms are bad and use our pollen calendar to see which pollen could be your trigger, and when it’s likely to be released.

Get set for pollen season

Different pollens are released at different times, but our changeable weather makes it hard to predict exactly when.

  • If you regularly get hay fever and take antihistamines, start taking them up to four weeks before you normally get symptoms. Starting them early means that when pollen starts being released, the medication has already built up in your bloodstream so you may be less likely to react.
  • If you usually use a steroid nasal spray, it can take up to two weeks to start working, so again, start using it before your personal pollen trigger is released. 

Three steps to reduce the risk of hay fever triggering an asthma attack

  1. Carry your reliever inhaler (usually blue) every day. If you have asthma, hay fever can cause your already inflamed airways to swell up even more. It can also make you more likely to react to other triggers like dust or pollution, and if hay fever combines with viruses like colds or flu, the extra inflammation can make your asthma symptoms even worse. Reliever inhalers quickly relax the muscles in your airways and ease your symptoms on the spot, so it’s important to carry your reliever inhaler with you.
  2. Take your preventer inhaler as prescribed. For long-term control of asthma symptoms, your GP might prescribe a preventer inhaler. This reduces sensitivity and swelling in your airways, helping to stop wheezing and coughing before they even start. Make sure you take your preventer inhaler exactly as prescribed to reduce the risk of hay fever triggering your asthma symptoms.
  3. Blitz hay fever symptoms with antihistamine pills and sprays and/or a steroid nasal spray. There are lots of different medicine options for hay fever. Your pharmacist can help you decide what to try.

See your GP if your asthma is getting worse

If you have hay fever, it’s likely that it’s triggering your asthma symptoms if you:

  • feel wheezy
  • feel breathless
  • have a tight feeling in your chest
  • are coughing more than usual
  • are needing to use your reliever inhaler three times a week or more 

If you start treatment quickly, you can get on top of your symptoms and reduce your risk of a potentially life-threatening asthma attack. Ask your GP for an urgent, next day appointment.

If you don’t think you have hay fever, but your asthma is getting worse, you should still see your GP urgently. You don’t have to put up with your asthma symptoms.

Hay fever, pollution, hot weather and thunderstorms

Lots of people find their hay fever is worse when there’s high pollution, especially when hot weather makes pollution worse. Pollution molecules stick to pollen grains, so they hang about in the air longer and are harder to get out of your airways.

Thunderstorms can also cause your symptoms to flare up, because they smash pollen into tiny bits that go deeper into your lungs.

These three steps will reduce your risk of an asthma attack from pollen combined with heat and/or pollution or thunder:

  1. Make sure you carry your reliever inhaler. If you need to use it three or more times a week, book an urgent GP appointment.
  2. Try to stay away from the trigger – don’t go out in the heat or if pollution is high.
  3. Take hay fever medicines to help reduce the allergic reaction that’s making your asthma worse – see our hay fever treatments page.

Pollen calendar


Last updated March 2020

Next review due March 2023