Sensitive individuals often develop an allergic reaction to birch trees known as a birch tree syndrome. The syndrome is considered an oral allergy because of its effects on the mouth. In western Europe, up to 54 percent of the population suffers from allergies related to birch tree pollen, according to Allergy Net. The most prevalent birch tree to cause the syndrome is the silver birch. Allergy sufferers should take care when planting birch trees in the landscape since the syndrome can develop over time.
Symptoms include an odd, tingling feeling in the lips or tongue. A rash often develops around the mouth, on the lips, tongue or interior of the cheeks. Swelling can also occur. In severe reactions the sufferer may have extreme swelling of the throat, which can result in anaphylaxis if emergency medical care is not sought, according to the Mayo Clinic.
Individuals who suffer from a birch tree pollen reaction may also have a similar allergic reaction to certain fruits such as apples. Other common fruits and vegetables that share a similar allergic reaction when consumed by sufferers of birch syndrome are carrots, hazelnuts, pears, peaches, raw potatoes and celery. The proteins within the fruit are similar to the pollen produced by the birch tree. If the fruits or vegetables are cooked prior to consumption they will rarely cause an allergic reaction in sensitive individuals.
The silver birch tree grows to a height of approximately 50 feet. The tree's bark appears white and often flakes or peels from the tree. The tree produces catkins that measure up to 2 inches in length and produce abundant pollen. Pollen production begins in February and extends into May in the northern hemisphere. In the southern hemisphere, the tree begins catkin production in August and it runs through October. The pollen of the tree is prolific and wind driven
The birch tree syndrome was first discovered in allergy sufferers in 1942 when a correlation was made between sufferers who consumed hazelnuts and apples but also appeared to suffer from a reaction to birch tree pollen. All patients with a history of a food or vegetable allergy should be checked to determine if they also suffer from a birch tree pollen allergy. It is believed that 35 to 65 percent of people who suffer an allergy to fruits or vegetables also suffer from a birch tree pollen allergy, according to Auckland Allergy Clinic.
Antihistamines can help alleviate the sufferer's symptoms. Immunotherapy, which involves injecting the patient with small amounts of pollen subcutaneously to build up immunity, is also being tried in those suffering from a birch tree allergy. Sufferers should consider staying indoors during the midday when the pollen count is at its highest. When the tree is actively producing catkins allergic individuals should keep the windows in their home and car closed. Consider showering often to wash away the pollen that might cling to hair. If birch trees grow on the property have them professionally removed and plant species that do not produce allergies.