What causes hay fever & rhinitis?

Aspergillus fungusThere are more than 30 types of pollens and 20 types of spores (pictured) that can trigger hay fever.

Some people's hay fever symptoms are triggered by just one or two types, others are affected by more.

Pollen and spores

  • Grass pollen is the most frequent cause of hay fever. In the UK about 90% of people with hay fever are allergic to grass pollen
  • Tree pollen can also cause problems. Troublesome trees include the alder, horse chestnut, hazel and birch. The birch is the most common culprit, though. In the UK between 15% and 25% of people with hay fever are allergic to birch pollen
  • Weeds like plantains, mugwort, nettles and docks also produce bothersome pollen
  • Wind-pollinated flowers (eg the Daisy family) are another common source of problems
  • Spores are produced by fungi such as mushrooms, and moulds like those in compost heaps
Different pollens and spores are released throughout the year. To identify which ones you are allergic to, make a note of when your symptoms occur.

What causes perennial rhinitis?

The major indoor allergens that cause perennial rhinitis are the house-dust mite and furry and feathery animals. Other allergens that can cause problems all year round are moulds, certain chemicals and foods.

Unfortunately it can be very difficult to identify exactly which allergen/s are causing your problems. It's a good idea to keep a diary card. Record the times when your symptoms are worse and try to identify what might have triggered them. Discuss the results with your GP. They may be able to help you identify your main allergens. Occasionally, your doctor may suggest referring you to a specialist for allergy testing.

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