Tomato contact dermatitis

The tomato plant (Solanum lycopersicum) is an important crop worldwide. Whereas immediate-type reactions to tomato fruits are well known, contact dermatitis caused by tomatoes or tomato plants is rarely reported. The aims of this study were to present new data on contact sensitization to tomato plants and review the literature on contact dermatitis caused by both plants and fruits. An ether extract of tomato plants made as the original oleoresin plant extracts, was used in aimed patch testing, and between 2005 and 2011. 8 of 93 patients (9%) tested positive to the oleoresin extracts. This prevalence is in accordance with the older literature that reports tomato plants as occasional sensitizers. The same applies to tomato fruits, which, in addition, may cause protein contact dermatitis. The allergens of the plant are unknown, but both heat-stable and heat-labile constituents seem to be involved. The fruit contains fragrance compounds that are also present in Myroxylon pereirae (balsam of Peru), possibly accounting for cross-reactivity. The proteins in pulp and peel may contribute to protein contact dermatitis. Until more is known about the allergens, the diagnosis of contact dermatitis caused by tomato plants and fruit may be established with the use of ether extracts and fresh fruits, respectively.