Focus on pollens
The main types of pollen responsible for allergic reactions are produced by wild or cultivated plant species all around us (trees, grasses and herbaceous plants).
Tree pollen: a range of different pollen types
There are six main families of trees which cause allergic reactions:
- Betulacae: birch, alder, hornbeam, hazel
- Cupressaceae: cypress, juniper, thuja
- Fagaceae: beech, chestnut, oak
- Oleaceae: olive, ash, privet
- Pinaceae: fir, pine, spruce, larch, cedar
- Platanaceae: plane
Ornamental trees often found in parks, gardens and cities, such as the cypress, the ash and the birch are highly allergenic.
Tree pollen is responsible for over 30% of allergic rhinitis cases1.
The pollen season extends over a long period from January to June , and varies widely from species to species.
Pollen from wild or cultivated grasses
There are two major families of grasses, comprising around 20 species:
- Cereals: oats, wheat, maize, barley, etc.
- Fodder grasses: cocksfoot, timothy grass, sweet vernal grass, rye grass, meadow grass, etc
They are found in gardens, lawns, meadows, crops, ditches and along roadsides. Light and very small, grass pollen grains are dispersed by the wind over tens or even hundreds of kilometres.
Grass pollen is highly allergenic and is responsible for over 50% of allergic rhinitis cases1.
The pollen season lasts from April to September with peaks in May and June.
Grass pollen: « weeds »
Herbaceous plants are a family of perennials. The most highly allergenic pollen is produced by ragweed, an invasive grass from North America, and mugwort, which is widespread on waste ground and alongside roads and pathways.
Pellitory, plantain and goosefoot can also cause allergies.
25% of allergic rhinitis sufferers are allergic to grass pollen1.
The grass pollen season lasts from April to September but is at its height between July and September.
 Bauchau V, Durham SR. Prevalence and rate of diagnosis of allergic rhinitis in Europe. Eur Respir J. 2004 Nov;24(5):758-64.