How would an allergy/intolerance to rice present itself?

Hives: Hives, itching, diarrhea, wheezing.

Uncommonly: Rice is one of the foods that is typically included with exclusion diets, because it is rarely a cause of allergic reactions. Any food allergy can cause respiratory problems/asthma, rash, diarrhea, pain, etc. Generally, would occur in people with a history of more general allergic reactions.