The hearty bite in the crunchy apple is suddenly no more enjoyment, but ends with a nasty surprise: an unpleasant tingling and burning sensation on the lips, on the palate and in the throat. When things get really bad, the throat swells and the air runs short. Acute respiratory distress or a circulatory collapse even mortal danger exists. Those who suspect pesticides on the apple skin as a cause, is wrong here: It is a cross-allergy, which occurs in hay fever patients with an allergy to certain pollen more frequently.
Professor Karl-Christian Bergmann, Head of the Allergy and Asthma Clinic in Bad Lippspringe and Member of the Board of the German Society for Allergology and Clinical Immunology (DGAI): "About 15 to 20 years ago, about 17 percent of hay fever patients suffered from a cross allergy Almost 60 percent, where there is a great need for information! "
Unfortunately, it is often a real detective work to get the allergy-causing substances on the track and find out what foods contain the culprits. "Food allergies should turn to an allergist, " advises Professor Bergmann, "omitting all sorts of foods on your own usually ends in a shortage of important nutrients.
This creates a cross allergy
The cause of a cross allergy or "pollen-associated food allergy", as the medical term is called, is an immunological cross-reaction: the allergens from grass, herb or tree pollen resemble in their structure certain proteins from fruits or vegetables. If the immune system is sensitized to a pollen allergen, it also goes crazy when in contact with similar structures from other plants.
Tree pollen allergy sufferers therefore often do not tolerate apples, cherries, plums, nuts, kiwi and strawberries. People with grass and cereal allergy can have problems eating cereal products and legumes such as peanuts or soy. For herbal pollen allergy sufferers, especially with allergy to mugwort, celery, carrots and many spices can be dangerous.
However, it is not just pollen allergy sufferers who need to be careful: allergies to natural rubber latex (such as rubber boots) may cross into bananas, kiwi, and avocados, and house dust mite allergies are often sensitive to seafood such as mussels or crustaceans.
Danger from undeclared ingredients
It goes without saying that the allergenic food must be avoided. In general, only raw fruits or vegetables are not tolerated because the allergenic proteins are sensitive to heat and are destroyed by cooking or baking. Unfortunately, soy, peanuts, nuts and celery, which are often hidden in foods, contain heat-stable allergens.
Undeclared celery in spice blends or peanut and soybean admixtures in prepared foods can cause a life-threatening anaphylactic shock in allergy sufferers. The German Society for Allergology and Clinical Immunology (DGAI) therefore believes that a directive on maximum amounts of allergens is urgently needed at EU level. Especially foods of a "hit list" of the most common allergy triggers should definitely be labeled: nuts, peanuts, celery, soy, peas, milk and egg white.
But even then, there remains a residual risk due to contamination. For example, in the chocolate industry, nut allergens may actually go into nut-free chocolates if nut chocolate was previously made with the same machinery. Priv-Doz. Dr. Stefan Vieths, food chemist at the Paul-Ehrlich-Institut: "In varieties where no nuts were used as ingredients, we found 100 micrograms of protein from hazelnuts or peanuts per 100 grams of chocolate, sometimes significantly higher levels sufficient to cause allergic reactions.
Allergy vaccination also helps with cross-allergies
Antiallergic drugs such as antihistamines help against the symptoms of pollen-associated food allergy. Patients who have already had an allergic shock from food should be provided with an antihistamine, cortisone and adrenaline spray emergency kit. "Above all, it is important to have an allergologically-trained specialist test exactly what triggers you are responding to" recommends Professor Bergmann, "then the immune system can be made tolerant to the allergens by a specific immunotherapy."
Specific immunotherapy, also known as hyposensitization or allergy vaccination, is currently the only causally effective therapy for allergies. Small amounts of an allergen preparation, the immune system is used to the allergy triggers. Even in the first year of treatment, the symptoms improve. The effect lasts for a long time after the end of the usually three-year therapy. Specific immunotherapy with modern, molecularly standardized preparations helps up to 90 percent of hay fever patients and can also improve food allergy. The best time to start the therapy is the early autumn after the end of the pollen count