Although tomatoes are a commonly consumed food, severe
allergic reactions to tomatoes are unusual or rarely reported. Previously reported allergic manifestations to tomato include
urticaria/
angioedema,
dermatitis, oral
allergy syndrome,
rhinitis, and
abdominal pain. The aim of this study was to report two patients with significant
immediate hypersensitivity reactions to tomato and characterize the responsible
allergen. We reviewed the history and documentation of tomato-specific
immunoglobulin E (
IgE) of two patients with adverse symptoms after ingesting tomato. Fresh tomato extracts prepared from the skin, seeds, and flesh of red, ripe tomatoes were evaluated for total
protein content and
sodium dodecyl sulfate-
polyacrylamide gel electrophoresis (SDS-PAGE) was performed to characterize the tomato
protein.
IgE enzyme-linked
immunosorbent assay (ELISA) using the patients' serum against the various tomato extracts was accomplished and
IgE immunoblot was performed. Percutaneous skin tests or radioallergosorbent tests (RASTs) were positive to tomato in both patients. Both adults experienced
laryngeal edema and one had
anaphylaxis. Similar total
protein contents were found in each of the tomato extracts and gel electrophoresis revealed similar
protein profile for skin and seed extracts with
protein bands discernible at molecular weights of 21, 33, and 43 kDa. One patient reacted specifically to a 43-kDa
protein band on
IgE immunoblot. The two cases show that severe
allergic reactions to tomato occur in adults and one is associated with
IgE binding to a 43-kDa
protein.