What are the pollens that most frequently cause allergy?
Considering allergenic pollens as a whole in Spain grass pollens are the most important cause of hay fever followed by olive pollens and Parietaria pollens (a weed). However olive is the first cause of hay fever in some places in the south of Spain (e.g. Jan, Crdoba, Granada), and the same occurs with the Parietaria in the Mediterranean coast (in these places grasses are the second cause of pollinosis). Other important allergenic pollens in Spain are Plantagos (May-June), Chenopodium and Artemisia (August-September). In the last few years the clinical relevance of some tree pollen such as Cupressus (Jenuary-March) and Platanus (March-April) is also increasing. Betula pollen is one of the most important causes of hay fever in Scandinavian countries, fortunately its pollen concentration in Spain is only limited to the north of Spain and with a moderate presence (March). Ambrosia is the most important cause of pollinosis in USA, luckily at the moment its presence in Spain is very rare. Ho