See your Allergist. The first step would be to discuss with your board certified allergist what exactly happens when you eat seafood. If your history suggest an allergy reaction then you should be skin tested to clarify / confirm your history. If your history and skin test conform a shellfish allergy then strict avoidance is necessary. You should also be prescribed an injectable form of Epinephrine to have available.
Sorry No tricks . To do so. If you have been seen by an allergist to confirm this , then avoid the foods and just wait. Many people "outgrow " the allergy in ?5-10 years. But be sure to be retested by an allergist.
You can't. Unlike some other food allergies, seafood allergies are not normally outgrown.