Lychee only contains one allergenic protein, a profilin called Lit c 1, it is found in significant quantities in the plant.
I have put together some more comprehensive resources at http://www.allergyresources.co.uk/Lychee.php
The allergy resources page for lychee covers the key allergens, which allergic syndromes are linked to this allergy and other foods which are commonly cross reactive with lychee.
There is also regularly updated links to useful websites specifically for lychee allergies and the latest research papers on the topic.
If you have multiple allergies and are interested in how they are linked or want to find out more about food allergies outside the usual top 14 then you can follow me on Facebook or Twitter, where I share a food allergy card every day of the week.