Oral allergy symptoms include itching, tingling or swelling of the lips, mouth and throat. These symptoms usually start within minutes of eating and settle down within an hour.
Oral allergy syndrome (sometimes called pollen food syndrome) is an increasingly common allergic condition in children, with an estimated 1 in 20 children affected.
It is usually found in hay fever sufferers, and occurs when the body, which is already sensitised to a particular pollen, encounters a related protein in the form of the associated fresh fruit, nuts, raw vegetables, or spices. In these cases, those affected by oral allergy syndrome usually already have an allergy to either tree, grass or weed pollen.
An allergy specialist will take details of the allergic reactions to decide whether there is evidence of a more serious allergy and will advise if adrenaline should be carried. This is particularly important for those with nut reactions.
Allergy skin prick tests will usually be needed to determine the specific allergen. A blood test for antibodies may be taken, but is not usually necessary if a full range of skin prick tests are available.
In most cases children will be able to continue eating the fruit or vegetable if cooked, because it is thought that the cooking process changes the food protein enough that the immune system does not recognise the food as an allergen anymore.
There are some exceptions to this, and if a child continues to show even a mild reaction to the food when cooked, or the reaction is specific to celery or nuts, then it may be safest to avoid these even when cooked. Also, if a child has had serious reactions such as breathing difficulties or shock, the foods should be avoided in any form.
Cooking a food can change its allergenicity, but this is not a reliable means of preventing reactions. If a food allergy has been diagnosed, the child must avoid the food(s) they are allergic to, even if these foods are cooked, unless specifically directed otherwise by their doctor.
Last updated: March 2012