I am allergic to shellfish. That is my food allergy.
That's horrible!  What causes shellfish allergy?
I have no idea why I have an abnormal immune response to shellfish.
Interesting.  Is there medicine or a treatment for the condition?
I am not sure but my symptoms have only mild.
What happens to you when you have the allergic reaction?
I usually get itchy and sometimes vomit.
That's no fun.  Is that the only thing you are allergic to?
Yes it is and it usually doesn't cause many problems.
That's good.  Was the allergy acquired or were you born with it?