Anaphylactic reaction to apple, banana and lychee: what is common between botanically disparate plant families?

We present the case of a 33-year-old nonatopic woman with multiple episodes of anaphylaxis after ingestion of different fruits. The fruits implicated were apple, banana and lychee: all of which belong to different and botanically disparate plant families. The reaction to apple and banana was confirmed by prick testing. There was no history of allergy to other agents that are known to have cross reactions with fruits, viz. latex or pollen. As such patients often do not present to dermatologists, we wish to highlight the rare but potentially fatal clinical entity of type I allergy to fruits without concomitant allergy to other common airborne/contact allergens. We also discuss the possible explanation of type I reaction to apparently unrelated fruits and the allergens involved in such reactions.