Cross allergy: pollen allergy sufferers should be careful with these foods

What is cross allergy?

Why should I give up apples if I'm allergic to birch pollen? About 70% of sufferers of a tree pollen allergy (e.g. birch, alder, hazel) have cross-allergies, also called cross-reactions with food because their proteins are very similar. Our immune system can't distinguish whether the proteins are those of birch or apple. It only recognises the allergen as dangerous - and a cross-reaction occurs.

Symptoms of cross-allergy

Anyone suffering from hay fever and experiencing the following symptoms while eating should avoid these foods, at least during the pollen season.

The following cross-allergies are typical

Many proteins, and thus allergens, are destroyed when cooking or heating and can therefore still be eaten.

January–April: birch, alder, hazel

Pome and stone fruit (apples, pears, plums, apricots, cherries, etc.), hazelnuts, walnuts, almonds, tomatoes, carrots, celery, mango, avocado, fennel, kiwi, lychee.

July–August: mugwort

Celery, carrots, fennel, artichokes, chamomile, pepper, mustard, dill, parsley, coriander, caraway, aniseed, sunflower seeds.

May–July: grasses

Allergy to grasses can cause sensitivity to certain foods, such as peanuts, potatoes, soya, kiwi, tomatoes, melon, cereals, peppermint. However, these don't usually cause an allergic reaction when eating these foods.

Latex or house dust mites

But cross-reactions with food aren't always triggered by pollen alone. An allergy to latex or house dust mites can also cause a reaction.

• House dust mites: shrimps, lobsters, crawfish, crabs, snails
• Latex: avocado, banana, sweet chestnut (vermicelli, chestnut), kiwi, papaya, fig, paprika

Possible treatment

1. Heating foods: certain allergenic foods are tolerated after being baked or cooked, as the heat destroys many of the allergens they contain. But be careful: while most people can safely eat an apple pie, for example, allergens in hazelnuts, peanuts, celery or spices such as cinnamon or coriander are heat-resistant and should therefore be avoided.
2. Desensitisation: pollen therapy – consisting of several small injections under the skin – also relieves the cross-allergy in many cases.
3. Medication: antihistamines, mast cell stabilisers or glucocorticoids – taken in the form of tablets or nasal sprays, for example, and used to treat pollen allergies – can stop the symptoms of a cross-allergy.
   

Risk of anaphylactic shock

In the worst case, the allergy triggers respiratory distress or circulatory arrest. In the case of a so-called anaphylaxis, it's vital that allergy sufferers know the most important rules of behaviour and emergency measures, but also how to avoid potential allergens. CSS has joined forces with the aha! Swiss Allergy Centre to offer a course for adults, young people, and parents of affected children.

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