Medical and severe allergies

Has anyone on this list had experience with getting a student his
medical certificate if the student has severe allergies? This student
has a really bad peanut alergy. If I eat a peanut butter sandwich
before a lesson we could get hives and if he were to accidently eat a
peanut he could go into shock. He carries an Epipen and makes sure
those around him know how to use it.
I'm just curious if anyone on this list has any first hand experience
with getting a medical under these conditions. Is it somewhat straight
forward, very hard, or not possible?

Thanks!
-Robert