What is oral allergy syndrome?
This term is given to an allergic condition in which people have symptoms of itching and swelling of the mouth, tongue and soft palate after eating fresh fruit. This can include eating fresh apples, pears, cherries, plums, peaches or apricots, but when cooked fruit or jam are eaten no symptoms occur.

What are the symptoms?
The symptoms are usually confined to the mouth although a small minority of people with Oral Allergy Syndrome do experience other symptoms, for example: urticaria (nettle rash), wheeze in the chest, or abdominal pain.

What can be done?
Most people who have Oral Allergy Syndrome suffer from hay fever symptoms (itchy eyes/nose, runny eyes/nose, sneezing) between February and July for a number of years before they develop Oral Allergy Syndrome. This is because the cause of Oral Allergy Syndrome is a cross-reaction between tree pollen, grass pollen and fruit proteins. These proteins can be destroyed by heating or cooking the fruit. If the symptoms are only focused in the mouth, and only occur when eating raw fruit, it should be perfectly safe to eat cooked fruit or jam. However, if symptoms are more widespread, eg: wheezing or abdominal pain, then the fruits which cause symptoms should be avoided completely.
Not all people are sensitive to all the fruits mentioned here, and it is not unusual for people who have had hay fever for many years to suddenly develop a problem with apples and then, after a few more years, to have problems with other fruits. There is, at present, no easy way of predicting who will develop a problem with any particular fruit.
As there is a known link with grass and tree pollen, an allergy skin test can be performed to these allergens, especially if a history of hay fever symptoms is expressed.
The fruit allergens, eg: apple, pear, etc., may be difficult to test as the specific proteins are destroyed when the allergen extracts are made just as they are in cooking. The lab may test you with fresh fruit sap by pricking the fruit and then pricking the skin. This test may be useful to confirm that you have Oral Allergy Syndrome.

For further information and advice contact:

British Allergy Foundation
Deepdene House
30 Bellgrove Road
WELLING, Kent DA16 3BY 
Tel: 023 8303 8792 

Anaphylaxis Campaign
PO Box 149
FLEET
Hants GU13 9XU
Tel: 01252 318723