Certified medical device Class IIa
Birch trees have a white shiny trunk and usually reach a height of 7 meters after only six years. Fully grown they are up to 30 meters high. The catkins hang in single small groups at the end of the branches and can be seen already in winter. The pollen can be recognized by the fine white-yellow powder, which is deposited on the body, clothing and many surfaces around us.
With up to five million pollen grains per birch catkin, the birch is one of the trees with the most pollen. Every two years, birch trees have what is known as the “mast year.” During this time, they shed particularly large amounts of pollen. A single tree can produce up to 100 million pollen. The main allergen is Bet v 1.
Depending on the weather, the pollen count can start as early as March. The main flowering period takes place around the end of March to the end of April. Birch catkins release the most pollen at temperatures between 15 and 25 degrees.
Possible cross reactions
Birch shows the most frequent cross-reactions to the pollen of hazel, alder and hornbeam. According to information from the German Allergy and Asthma Association (Daab), cross-allergies occur in more than half of all birch pollen allergy sufferers. Cross allergies are mostly to raw seeded and stone fruits as well as nuts. According to the German Federal Institute for Risk Assessment (BfR), birch pollen allergy sufferers should however also be careful with soy products. The trigger of the cross-reaction to soy products is usually the allergen Gly m 4. This is found in non-fermented soy products such as soy drinks, soy flakes, soy yogurt, diet powder or tofu.