In the diagnostic interview, the doctor will first ask what conditions have occurred and what has been eaten and drunk prior to the event itself. For symptoms that remain or are permanent, it may also be helpful to record this for a few days or weeks in a diary with information about food eaten and subsequent symptoms.
As with other allergies, a skin test and blood test can provide information for detecting food allergies. In the blood test, it is checked whether the body has formed certain antibodies (usually IgE antibodies) to a food. When a skin test solution is mixed with protein from food, the slightly scarified skin is observed to see if it becomes red or hives or itches.
Also, an elimination diet can help with the diagnosis. Suspect foods are exempted for one to four weeks and recorded in a nutrition diary as symptoms develop.
To detect a food allergy, a provocation test is usually needed, in which suspect foods are consumed under medical supervision.
It’s about triggering symptoms on purpose. Depending on the suspected severity of the allergic reaction, the test is performed in the clinic under emergency conditions.
The allergy tests are repeated regularly in children and adolescents to see if they can tolerate the food again. The time depends on the type of trigger: milk allergy, for example, is tested in shorter intervals than in cases of allergy to nuts or peanuts, since the milk allergy often returns after a few years. In infants and young children, only blood is tested and skin tests are skipped.
What tests are inadequate for diagnosis?
The determination of other antibodies in the blood (called IgG/IgG4 antibodies) is offered in some practices as a private performance. However, this study is currently not recommended because it may backfire.
Above all, non-health professionals offer “alternative” allergy tests. These tests include, for example, bio resonance, hair analysis, iris diagnosis or the ALCAT test, a blood test to detect inflammatory reactions. However, such methods are not suitable for detecting an allergy.
How are food allergies treated?
The most important treatment is to give up allergy trigger foods. How this works depends on the food. A nutritional consultation or training program can help: There the patient will learn how to avoid allergy triggers and replace them if necessary. You learn to recognize the corresponding foods when shopping, during preparation, or when visiting restaurants. Also, dealing with anaphylactic reactions is a problem.
Until now, drugs have played a minor role in treatment. However, the few studies suggest that so-called H1 antihistamines can alleviate acute skin problems.
A desensitization (immunotherapy), as is possible with other allergies, is not yet available for food allergies. There are several studies that have verified the effectiveness of hypo sensitization in various food allergies. However, to what extent it works in the long term has not yet been clarified enough.
Prebiotics and probiotics are sometimes claimed to be effective in treating food allergies. Despite some studies, however, there is no evidence so far.
To treat an anaphylactic reaction immediately, it is important to go to a medical center as quickly as possible, especially if you have severe symptoms such as shortness of breath.
It is not advisable to self-medicate with epinephrine or antihistamines, as the consequences can be serious without the supervision of a health professional.
What foods should I replace?
Some foods such as nuts, fish or meat can generally be dispensed with without health disadvantages. Others have to be replaced in certain cases, otherwise important nutrients such as protein or calcium are lost. Especially with children, it should be checked regularly whether the exemption of certain foods is still necessary.
For babies, cow’s milk can be replaced by a special low-allergen food, a so-called hydrolyzed food. Soy milk is not recommended for children under one year of age because some babies do not tolerate it well.
How can I tell if a food contains allergy triggers?
There is a legal labeling requirement for the most important food components that can trigger allergies. It currently contains 14 substances and products:
- Gluten-containing cereals such as wheat, rye, barley or oats.
- Nuts such as almonds, hazelnuts and walnuts.
- Sesame seeds.
- Shellfish and mollusks (such as mussels, oysters, or squid).