How long does raw shrimp allergies last?

Long, long time: Shrimp allergies tend to persist compared to other food allergies. Even when cooked, the major shrimp allergen is resistant to heat. Shrimp (and other shellfish) are more likely to cause severe allergic reactions like anaphylaxis. The major shrimp allergen called tropomyosin (in the meat/muscle) can cross react with house dust mite. The reaction has nothing to do with iodine.