| Gareth,
I suffer food intolerance (rather tha severe allergic reaction), in as much that I come down with hay fever like symptoms if I eat dairy produce, so I also need to be careful what I eat. Mainly mine is controlled through diet and Beconase (nasal spray), although the reaction does take a while to come on (and control) so I dont have the severe problem your friend does. Beconase I have seen as 'recommended' for people who suffer breathing problems as it actually opens up airways and obviously helps as far as a diver is concerned.
Hope you get the info you are looking for and your friend can dive.
Matt |