Allergies?

Me:  "You don't looks so good.  Are you feeling ok?"
Student:  "Yea, it's just allergies."
Me:  "What are you allergic to?"
(silence)
Student (looks befuddled):  "I'm not allergic to anything."
(silence)
Me:  "Seriously?  You just said you have allergies."
Student:  "Yea, but I'm not allergic TO anything."
(silence)
Me:  "What now?"
(silence)
Student:  "Well, I mean pollen and long-haired cats bother me.  So, I'm totally allergic to that stuff."