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.