In the case of a food allergy, the immune system reacts to harmless food components. Sometimes the consumption of certain foods can also lead to symptoms without the immune system being involved. Then there could be a food intolerance.
Food allergy – what is it?
Certain components of food, mostly so-called glycoproteins, can be classified as supposedly dangerous by the immune system when they come into contact with the gastrointestinal tract. This then reacts with the formation of allergen-specific antibodies of the IgE type. The next time you come into contact with the allergen, there is an inflammatory reaction that can manifest itself in various symptoms.
Doctors distinguish between primary and secondary food allergies. While primary ones arise as a result of sensitization in the gastrointestinal tract, secondary ones are so-called cross-allergies. This means that there is an allergy to other allergens, such as hay fever (pollen allergy). The immune system then sometimes reacts to similar substances in food.
In addition to food allergies – such as nut allergies – there are food intolerances that can cause similar symptoms. In contrast to an allergy, however, the symptoms are not caused by a reaction of the immune system, but mostly by the fact that certain food components cannot be broken down by the body or only insufficiently. For example, an intolerance to milk sugar (lactose) is common.
What symptoms can occur?
Food allergies belong to the so-called immediate type. The reaction starts shortly after the allergen is eaten. The symptoms can be extremely varied. Reactions on the skin or mucous membranes are common. They may itch, redden, swell, and form wheels. Complaints like a cold (runny nose, cough, hoarseness) are possible. Nausea, vomiting, diarrhea, and cramping abdominal pain may occur. In rare cases, life-threatening anaphylactic shock can even occur, with a standstill on the respiratory and cardiovascular systems.
How can a food allergy be treated?
The therapy of food allergies is mainly based on the treatment of acute symptoms and strategies to avoid further allergic reactions. In training courses, allergy sufferers can learn how to avoid allergy triggers and how to behave in the event of accidental contact. Drugs (antihistamines) are recommended to treat acute, non-life-threatening reactions. In severe reactions, adrenaline is used as an emergency injection. Specific immunotherapy for primary and secondary food allergies is currently only recommended within the framework of controlled studies unless there are concomitant pollen-related respiratory problems.
Most food allergies start before school age. In some cases, however, allergens are tolerated again after some time. There are good chances for early childhood milk protein allergies, allergies to hen’s eggs, wheat, and soy, but poor chances for nut allergies.