A nurse with anaphylaxis to stone fruits and latex sensitivity: potential diagnostic difficulties to consider.

BACKGROUND

There have been several recent reports describing a cross-reactivity between latex and antigens derived from a number of fruits, including those of the stone fruit family. The relationships between the allergic reactions to the antigens from these plant products are still being defined.

OBJECTIVE

To characterize the IgE reactivity of a patient who had anaphylactic reactions following the ingestion of several members of the stone fruit family (ie, plum, peach, and nectarine) and had a positive clinical history for latex allergy.

METHODS

The patient's serum was tested for the presence of specific IgE for latex, stone fruits, and a panel of other foods reported to be cross-reactive with latex. Prick testing was also performed with freshly prepared extracts from the implicated fruits. Finally, the immunochemical relationship between this patient's fruit and latex sensitivity was investigated by RAST inhibition.

RESULTS

The patient had strongly positive skin tests to the freshly prepared fruit extracts but the in vitro food-specific IgE tests were equivocal or very low positive. In vitro latex-specific IgE tests were strongly positive. The stone fruit extracts were shown to be inhibitors of the patient's latex specific IgE by RAST inhibition.

CONCLUSION

Skin testing with freshly prepared fruit extracts was more sensitive than the in vitro tests with this patient. The inhibition data support an immunochemical relationship between the patient's latex allergy and sensitivity to stone fruits.