Ristuv allergia

The most common pollen-allergens can be divided in six groups in a way that crossreactions are very likely between allergens of the same group, but are very unlikely between allergens of different groups. 

These groups are:

·  the birch-family

·  the grass-family

·  the composite-family (mugwort, ragweed, ...)

·  the olive-tree and ash-tree

·  the nettle-family (wall-pellitory)

·  the conifers (cypress, ...)
There are, however, several other allergenic plants described here, that do not fit into any of the above groups. Most of these plants can be put into a group with no known crossreactions. For the rest of them, you will have to have a look here. 

There is a EC-project named s.a.f.e. that deals with food-allergy. Here you can read much more about cross-reactions and the latest news.


Birch-pollen show crossreactions with pollen of: alder (Alnus), hazel (Corylus), hornbeam (Carpinus), hopbeam (Ostrya), beech (Fagus), oak (Quercus), sweet chestnut (Castanea) and sycamore or plane tree (Platanus).
There are also crossreactions between pollen of the plants listed above and the following foods: apple, peach, cherry, kiwi, maracuja, nuts (in particular hazelnut), almonds, carrot and tomato.


All the grasses, along with the cereals are cross reactive. High growing meadow grasses, such as timothy (Phleum), orchard grass (Dactylis), oat grass (Arrhenaterum), or ryegrass (Lolium), have the highest allergenic potency. The most important pollen from cereals is cultivated rye (Secale cereale). Some other grasses, like reed (Phragmites), oats (Avena), or bermuda grass (Cynodon) are less allergenic.
Grass pollen can cross react with food like cereals, peas, beans, lenses, soy, and peanut.


Mugwort (Artemisia) and ragweed (Ambrosia) pollen cross react with practically all pollen of the family, e.g. with all flowers that look like daisies (Bellis), ox-eye (Chrysanthemum), or sun-flowers (Helianthus), but also with goldenrod (Solidago), or Chamomile (Chamomilla).
Cross reactions with food allergens are: celery, artichoke, sunflower seeds, many spices (origan, basilic, absinth, nutmeg, white pepper, paprika and others).

Olive-Tree, Ash-Tree

Olive-tree and ash-tree cross react with: lilac (Syringa), forsythia, privet (Ligustrum) and jasmin (Jasminum).
Cross reactions between these plants and food are very unlikely.


The only important allergen is wall pellitory (Parietaria judaica).
Cross reactions with other Parietaria-species and with stinging nettle (Urtica), or with hop (Humulus), marijuana (Cannabis), mulberry (Morus) or elm-tree (Ulmus) are feasible.
Cross reactions between the plants listed above and food are very unlikely.


In Europe, the most important allergenic conifer pollen is that of cypress (Cupressus). A pollen producer with higher allergenic importance is the Japanese Cedar (Cryptomeria japonica) in Japan.
Cypress can cross react with juniper (Juniperus), arbor-vitae (Thuja), and `Port Orford cedar or nootka Cypress (Chamaecyparis). Some exotic pines (Pinus) might be allergenic as well and could eventually cross react with cypress. As in the nettel-family, cross reactions between the plants of the cypress-family and food are very unlikely.

Plants with no known crossreactions

These are the plants for which there are no crossreactions known yet: Elder, horse chestnut, lime tree, maple, mulberry, oil seed rape, plantain, sorrel, dock and tree of heaven.

The rest

Hop may show crossreactions with the closely related hemp (Cannabis sativa).
Lambs quarter, chenopods, mexican tea, pickleweed, firebush and saltbush crossreact only within their family.
Stinging nettle is known for crossreactions with wall pellitory.
Walnut crossreacts with hickory.