Introduction
If an itchy, reddish skin rash appears after eating tomatoes, this indicates an intolerance to tomatoes, which can have various causes. The itchy rash may contain fluid-filled blisters, large wheals or pustules filled with pus after an additional infection with bacteria. In addition to the skin, these can also show up increasingly on the mucous membranes of the mouth or throat. Frequently, other symptoms, such as gastrointestinal complaints, are added as an indication of the underlying cause in connection with food intake. Avoiding food helps to completely relieve the symptoms.
Causes
One reason for a rash caused by tomatoes can be a histamine intolerance. Histamine is present in some foods and is also found in large quantities in tomatoes, among others. Since histamine is released in the body as a messenger substance in the course of an allergic reaction, similar symptoms result in the event of intolerance.
Another cause is a cross-allergy, which occurs mainly in connection with pollen allergies. In this case, the body has specific antibodies for pollen allergens, which react due to structural similarity with molecules contained in the tomato and trigger an allergic reaction. If you are further interested in allergic skin rashes, we recommend that you read our article on rashes caused by allergy
Tomato Allergy
A “tomato allergy” is usually not based on an actual allergy to tomatoes. It is often a histamine intolerance or a cross-allergy. In the case of a cross-allergy, the body reacts with a classic allergic reaction on contact with the tomato, since antibodies that are actually specific for another allergen, often grass pollen, incorrectly recognize tomato molecules as their allergen and then trigger an allergic reaction.
For further information on this topic, please visit our allergy page. The allergic reaction to tomatoes in the context of a histamine intolerance is based on the high amount of histamine that tomatoes naturally contain. Histamine is a messenger substance produced naturally in the body, which is released in increased quantities in an allergic reaction and leads to the typical symptoms of an allergy, such as swelling, redness or itching. This explains why drugs that suppress the effects of histamine (antihistamines) are used to treat allergic symptoms. In the case of histamine intolerance, the additional histamine that enters the body from outside through the tomatoes cannot be broken down and an excess of histamine is produced, which leads to the symptoms of an allergic reaction.
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