I'd hate to be condemned to a life time without shrimp or shell fish. There's always the possibility that her hives outbreak had nothing to do with the shrimp. A referral to an allergist (sometimes covered by health insurance, if the MD will take it) can quickly establish the nature and extent of most food allergies.

As a caveat, I've a brother in law who is an allergist, and I think he puts his trust in God, but all others pay cash and file their own insurance claims.