Cross-reactions

Cross-reaction due to similar allergens are a possible source of risk for pollen allergy sufferers. The most famous example is the birch pollen-nut-stone fruit-syndrome that causes an allergic reaction when consuming an apple in a birch pollen allergy sufferer, because the immune system confuses the protein in apple (Mal d 1) with the protein in birch pollen (Bet v 1). The following symptoms indicate a cross-reaction due to food:

itching mouth and throat
swelling of mouth, tongue and lips
hoarseness
numbness
swelling of eye lids
digestion problems

The same principle applies to cross-reactions between pollen types, which originate mostly from close relationship. Important plant groups are listed in the following and cross-reactions usually occur within the group than beyond the group:

There are more plants of allergenic potency which do not belong to the lists groups of course. A few specialities are mentioned towards the end of this text. The most common cross-reactions of pollen and/or food are listed within their group, but are limited on the most common causes and not exhaustive (especially concerning the rare sources of cross allergies and because of the individual reaction).

pollen from:
birch,
alder,
hazel,
hornbeam,
hop hornbeam,
beech,
oak,
chestnut,
plane tree.
food:
stone fruit like apple, peach, cherry,
nuts (especially hazelnut),
almonds,
tomatoes,
celery,
carrots,
exotic fruits like jackfruit, avocado, kiwi, lichi, passion fruit and mango.

In general, grass pollen cross-reacts among one another (here more about grasses) and with cereals (here more about rye). However, not every grass species must affect every grass pollen allergy sufferer. Particularly allergenic are from a current point of view:
cocksfoot,
oatgrass,
ray grass,
and rye amongst the cereals.
Less of a concern seem to be reed, oat and bermuda grass.
food:
cereals,
cereal flour,
potatoes,
tomatoes,
peas,
beans,
lentils,
melon,
soja,
peanuts.

Pollen from:
ragweed (Ambrosia),
mugwort,
goldenrod,
daisy,
marguerite,
sunflower,
camomille.
food:
melon,
banana,
camomille,
celery,
artichoke,
sunflower seeds
and spices (aniseed, oregano, basil, vermouth, tarragon, nutmeg, white pepper, sweet pepper).

Pollen from:
ash,
olive (tree),
lilac,
forsythia,
privet,
jasmine.
Cross-reactions with food were not apparent up to now for this group.

Pollen from:
nettle,
wall pellitory,
hop,
hemp,
mulberry,
elm.
Cross-reactions with food were not apparent up to now for this group.

In general, allergies to conifer pollen are less known in our area. However, they are an increasing problem in Mediterranean regions.
Pollen from:
cypress,
juniper,
thuja,
false cypress,
some exotic species of pine trees,
Japanese cedar.
Cross-reactions with food were not apparent up to now for this group.

Pollen from poplar and willow is cross-reactive.

Pollen from hop and hemp probably cross-reacts.

Pollen from walnut, hickory and wingnut is cross-reactive.

Cross-reactions has to be assumed for pole of several representatives of the family.

More information about cross-reactions based on other allergies (e.g. house dust mite allergy, animal-hair-allergy) can be found here.

The new labelling requirement according to EU regulations applies since the 13th of December 2014 is unpopular for many who try to decipher the remarks, but is a significant easement for food allergy sufferers. The 14 most common product groups that can be responsible for food allergy have to be noted (cereals containing gluten, eggs, crustaceans, fish, peanuts, soma, milk, nuts, celery, mustard, sesame, lupines, molluscs and the additives sulphur dioxide and sulphites).