Cross-allergies occur more and more frequently in connection with hay fever. Those who suffer from a pollen allergy not only have to forgo spring walks – often a bite into an apple or eating a peanut can also have serious consequences for allergy sufferers. This is because the immune system reacts hypersensitively to substances foreign to the body, the so-called allergens. Since some allergens, for example pollen allergens, are similar to those of some foods, allergy sufferers may experience so-called cross-allergies. Often it is certain fruits, vegetables or nuts that trigger such a cross-allergy.
Hay fever: triggers of cross allergies.
Hay fever is often called pollen allergy because it is triggered by pollen from grasses, trees or herbs. Depending on which substances cause the allergy, the intensity of symptoms can vary seasonally:
- Typically, the pollen load is highest in the spring and summer months.
- Already in February or March, the first early bloomers awaken, which include alder and hazel.
- In the further course of the year, allergy sufferers mainly the pollen of the birch cause problems.
- The flowering period of grasses, on the other hand, typically ranges from May to August, so that an allergy to rye or oats sometimes becomes noticeable only in the summer months.
Probably one of the most allergenic substances is the mugwort. This wild herb can cause very severe discomfort even in small quantities. Since the allergy can spread to the bronchi and cause allergic asthma there, all cases of hay fever should be professionally treated by an allergist. The latter should also check whether the hay fever is accompanied by a cross-allergy.
What is cross-allergy?
The allergens of pollen and some foods are sometimes similar in their chemical structure. Because the immune system cannot always distinguish between the individual substances, people who are allergic to pollen are often also sensitive to certain foods. This is called “cross-allergy” or “pollen-associated food allergy“. However, cross-allergies do not only occur in connection with hay fever – other allergies are also possible triggers.
Common forms of cross-allergy
Which foods can cause symptoms depends on the type of allergy:
- Cross-allergy often exists between tree pollen and various fruits, vegetables, nuts and herbs.
- Who is allergic to birch pollen, often also shows discomfort when eating stone and pome fruits (for example, apple, pear, cherry, plum or peach), strawberries, tomatoes, hazelnuts or soy.
- A relationship also exists between mugwort pollen and certain spices, such as cumin, pepper or anise, but also with vegetables such as bell bell pepper, celery, carrot or cucumber.
- Allergies to grass pollen often cause hypersensitivity to other grains and various fruits, vegetables, nuts and spices (for example, rye, oats, melon, kiwi, peas, peanut or peppermint).
- Allergies to house dust are often accompanied by a cross-reaction to shellfish or crustaceans.
- Cross-reactions between similar foods are also possible, for example, between different types of nuts, cereals or fish.
- In case of allergy to penicillin, cross-allergy to a certain group of antibiotics may occur.
There is also a link between contact and food allergens. A typical example of a contact allergy is latex allergy. This form of allergy is often accompanied by an allergy to nuts, fruit (for example, avocado, banana or kiwi) or vegetables (for example, potato, celery or tomato).
How does a cross-allergy manifest itself?
Symptoms of cross-allergy usually appear immediately after food intake and are usually localized to the mouth area. For example, the following symptoms may occur:
- Swelling, tingling or itching of the oral mucosa.
- Blistering of the lips
- Redness of the skin around the mouth
Only rarely does the allergy spread to the entire body. In these cases, the following symptoms may occur:
- Hives
- Discomfort in the gastrointestinal tract
- Circulation problems
- Shortness of breath
In the worst case, a circulatory collapse, acute respiratory distress or even a life-threatening allergic shock threatens.
Treatment of cross-allergy with antihistamines.
Medications can relieve the symptoms of cross-allergy. Antihistamines, for example, reduce the effect of histamine, a chemical messenger produced naturally in the body. This is released in high levels during an allergic reaction and triggers the typical symptoms. Depending on the active ingredient, antihistamines are available as nasal sprays, eye drops, tablets, syrups or drops. They not only relieve the symptoms of cross-allergy, but are also used to treat hay fever. Occasionally, however, they can cause fatigue as a side effect.
Hyposensitization for cross-allergies.
Only a so-called hyposensitization can combat the cause of a cross-allergy in the long term. The aim of this treatment is to gradually accustom the immune system to the allergens. For several years, the patient is administered the specific allergen at regular intervals – usually via an injection. The dose is increased over time. Although this form of therapy is lengthy, it can counteract the cause of the allergy as the only known method. The treatment can lead to an improvement of the symptoms or even to the complete disappearance of the allergy. At the very least, however, the quality of life of those affected is noticeably improved. Hyposensitization can be performed in adults as well as in children. This form of therapy is particularly recommended for patients suffering from hay fever. Autumn is the best time of year to start treatment, as the general pollen load is low at this time. However, in severe diseases, such as asthma, this type of treatment should be avoided.
Do foods need to be avoided?
In the case of a cross-allergy, a complete avoidance of the allergy-causing food is the safest option to avoid the onset of symptoms – because sometimes even small traces of the allergen can trigger severe symptoms. However, many foods can also be made tolerable by heating or freezing them for a longer period of time. Especially fruits and vegetables can be “rendered harmless” by heating. Even in the form of mush, juice, jam or cake, many types of fruit, such as apples, are usually tolerated by allergy sufferers. Other allergens, on the other hand, are heat-resistant. This is especially true for nuts, celery, fish, soy as well as many other animal products. These foods should be avoided completely in case of allergy. Often, the discomfort of eating these foods occurs especially when the corresponding pollen is in flight. In this case, a seasonal renunciation of the respective foods can be useful.
Always keep an eye on the cross allergy
As an allergy sufferer, you should pay attention to which foods you eat. The question of the ingredients is always in the foreground. Especially with ready-made products, it is sometimes necessary to read the ingredients very thoroughly: For example, soy can be hidden behind descriptions such as “vegetable oil” or “emulator lecithin“. In order to find alternatives to the allergy-causing foods, it is advisable to draw up a diet plan together with a nutritionist. This procedure is particularly advisable if certain foods are to be avoided completely, in order to prevent malnutrition. In addition, allergy sufferers should have themselves examined by an allergist at regular intervals. Food allergies can weaken over time or disappear completely. An allergy test can help determine whether the allergy is still active. Keeping a food diary can also provide information about which foods may be harmful.
Always with you: the emergency kit
If an allergy has been confirmed or serious reactions have already occurred, it is advisable to carry an emergency kit. This contains antihistamines, cortisone and an adrenaline spray. In the event of so-called allergic shock, in which affected individuals go into a life-threatening state of shock, the medications contained in the emergency kit should be administered immediately after calling the emergency physician.
