Hay Fever (Seasonal Allergic Rhinitis)

Hay fever (seasonal allergic rhinitis) is caused by an allergic reaction to the pollen from grasses, plants and trees and in some cases fungal spores. A person suffering from hay fever may be allergic to one, several or many types of pollen.  Symptoms include sneezing, runny itching eyes and nose, sore throat, headache and tiredness.  In the UK, grass pollen is the commonest cause of hay fever but also important are pollens from trees such as alder, hazel, birch and plane, and from weeds such as nettles and from garden plants.

Some people suffer the symptoms of hay fever all the year round; a condition known as perennial Rhinitis.

In the UK, pollen grains (an artists impression of a single pollen grain is pictured on the right) can be found in outdoor air for nine months of the year, from February  to October.  Whilst the main problem for most hay fever sufferers is pollen form grasses that pollinate during June and July, trees pollinate from February onwards, and garden flowers, shrubs and weeds continue during the main grass pollen season and then on through the summer until October.  Typical pollen seasons for the UK are shown on a chart, although these seasons may vary by up to three weeks depending on which part of the UK, and depending on the climatic conditions.  In recent years there has been a tendency for pollination to start earlier as a result of milder winters, and warm spring weather conditions.

Other people have seasonal symptoms when exposed to fungal spores that proliferate from May until October, the height of the problem being August and early September.   Hay fever and asthma occurring following thunderstorms and on warm still summer evenings is likely to be caused by fungal spores.

We have provided a chart showing the seasonal occurrence of some of the main UK pollens.

When 'hay fever' symptoms occur all the year round, the condition is known as 'perennial allergic rhinitis', and the allergic causes are likely to be different.

How do I find out the cause of my hay fever?

If you suffer from allergic symptoms, you can only know for certain if you have an allergy if you have it confirmed by an allergy assessment.  This includes enquiring about symptoms, history of allergy, exposure, family history etc., to get a good picture of your situation and to see what can be done to help

When hay fever is caused by allergy to pollen grains, skin prick testing is usually helpful. These tests involve a gentle prick through a drop of allergen extract on the surface of your arm (pictured left). This may result in a small swelling and a reddening of the skin, suggesting that you have an allergy.

A blood test for specific allergy antibodies (IgE antibodies) is often recommended to confirm the test result. If specific antibodies towards one or more allergens are found in the blood, it means that you are sensitised and are liable, either now or at some time in the future, to have an allergic reaction when exposed to these substances.

When is the pollen season?

In the UK, pollen grains can be found in outdoor air for nine months of the year, from February  to October.  Whilst the main problem for most hay fever sufferers is during June and July, trees pollinate from February onwards, and garden flowers, shrubs and weeds continue through the summer until October.  Fungal spores proliferate from May until October, the height of the problem being August and early September.   Hay fever and asthma occurring following thunderstorms and on warm still summer evenings is likely to be caused by fungal spores.

What is the Oral Allergy Syndrome?

Some hay fever sufferers experience the Oral Allergy Syndrome throughout the year.  In the UK, it is commonest amongst patients who turn out to be allergic to the pollen of the birch tree, although some grass pollen sensitive patients are also affected.  In the most common form, sufferers experience a localised swelling or itching of the lips, mouth, tongue or throat immediately after contact with certain fruits or vegetables.  Reactions usually follow contact with the fresh fruit or raw vegetable (sometimes even handling them), although reactions to cooked foods can sometimes also occur.

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