Food allergies happen when the body's immune system has a reaction to a substance found in food. In the case of tomatoes this substance is often lycopene, although other components of the tomato may also to blame. Several food allergies are caused by the production of antibodies called immunoglobulin E. A 2002 study at the Medical College of Wisconsin, which was published in the journal "Allergy and Asthma Proceedings," showed that tomato allergies can also be caused by this antibody. Signs of tomato allergy include abdominal discomfort, anaphylaxis and rashes.
Abdominal Pain
Abdominal pain has been reported in the context of tomato allergy. Diarrhea, nausea, stomach pain, cramps, gas and vomiting have all been reported in the context of allergy to tomato based products and lycopene supplements. These reactions are rare as tomatoes and lycopene are generally well tolerated.
Anaphylaxis
Throat constriction leading to anaphylaxis is the hallmark of many serious allergic reactions. It is very rare in tomato allergies. When given skin tests to tomato, two adults known to have tomato allergies experienced laryngeal swelling. One even progressed to anaphylaxis, a constriction of the airways.
Skin Rashes
Tomato allergies can cause hives, swelling and dermatitis when affected individuals come into contact with tomatoes. These reactions may be caused by contact dermatitis, an allergic skin reaction to an irritating substance. Affected areas may itch, become red, swell and feel warm. This typically resolves in two or three weeks but symptoms can be alleviated with corticosteroids.
Testing
To diagnose your tomato allergy your physician may perform a patch test. Patch testing involves strips of tape containing small amounts of allergen. These strips are applied to your back and after two days the tape is removed. A small red spot will appear if you are allergic. A reaction can appear up to 96 hours hours after application of the tape.
References
- EczemaNet: Contact Dermatitis
- MedLinePlus; Contact Dermatitis; Linda Vorvick et al; November 2009
- "Allergy and Asthma Proceedings"; Severe Tomato Allergy; MC Zacharisen et al; April 2002
- National Institute of Allergy and Infectious Diseases: What is Food Allergy?
- University of Maryland Medical Center: Food Allergy
- MayoClinic.com: Lycopene Safety
