I count myself as one of the many that are allergic to seafood, specifically shrimp and crab. In my younger years, I found that I must stay away from food with those ingredients unless I want to end up with itchy red blotches all over my face and body.
While growing up, I discovered that certain things will allow me to enjoy seafood without very adverse effects.
1 - Devein the shrimp. Deveining removes the vein or the dark line that runs along the back of the shrimp. I noticed my allergies are less intense when eating deveined shrimp.
2 - Avoid the head of the shrimp. It seems whatever is causing my allergies, as far as shrimp goes, is heavily concentrated in the head so I stay away from it and eat the body only.
3 - Cider Vinegar and Pepper. I dip shrimp and crab meat in cider vinegar with pepper before I put it my mouth. I feel that it tastes really good and more importantly it seems to counter act the itchiness I usually get in my mouth after eating it.
4 - Lemon. I discovered this while dining at a UCC coffee shop. The water they served smelled like rubbing alcohol, at least it did to me. I inquired and it was in fact lemon and NOT rubbing alcohol. It seems dipping shrimp and crab in lemon has the same effect as cider vinegar and pepper. Alternatively, I found that I could chase away the itchiness in my mouth if I drink water with some lemon juice.
WARNING : The above are based on my personal experiences only. I classify my condition as mild. People with very serious reactions to seafood like shrimp or crab should consult a physician. As mild as the term "allergy" sounds, there have been known incidents of people dying due to allergic reactions. You have been warned !