Cross-reactions

Cross-reactions occur most frequently between food, pollen and latex, because their proteins are very similar. The symptoms are usually moderate.

What is a cross-reaction?

A cross-reaction is a group allergy to similar or related proteins. People affected display an allergic reaction to several seemingly unrelated substances at the same time. This usually involves a food allergy, the cause of which can be attributed to a pollen or latex allergy. Birch pollen-nut-pip fruit or mugwort-celery spice syndrome are common examples of a cross-reaction. Therefore someone who has become sensitised to birch pollen may also have an allergic reaction to apples and nuts and vice versa.

How can a cross-reaction be identified?

Sufferers from pollen allergy who experience a tingling in the palate, burning and itching in the mouth area and lips or even develop swelling affecting the face when eating certain foods should consider that they may have a cross-reaction.

How can they be prevented?

Anyone who notices tingling/burning in the mouth or throat should no longer consume the food concerned. Admittedly, a lot of proteins are destroyed by cooking and heating and the food can be eaten again. A frequent recommendation is to eat only small amounts of the food in question. Occasionally pollen therapy by means of desensitisation will also relieve the food allergy.

What are the most common cross-reactions?

Around 70 per cent of people who suffer from tree pollen allergies are found to have cross-reactions with foods. Fewer people with mugwort and grass pollen allergy are affected by cross-reactions. The following are typical:

Birch pollen-nut-pip fruit syndrome

Birch, alde, hazel (January–April)
Stone and pip fruit (apples, pears, plums, apricots, cherries, etc.), hazelnut, walnut, almonds, tomatoes, carrots, celery, mango, avoado, fennel, kiwi fruit, lychee.

Mugwort-celery spice syndrome

Mugwort (July–August)
Celery, carrots, fennel, artichokes, camomile, peppe, mustard, dill, parsley, coriande, caraway, aniseed, sunflower seeds.

Other typical cross-reactions

Grasses (May–July)
Peanut, raw potatoes, soya, kiwi fruit, tomatoes, melon, cereals, peppermint.

Editors: aha! Swiss Allergy Centre in co-operation with the Scientific Advisory Board.

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