Most people with shellfish allergy are allergic to crustaceans - shrimp, prawn, crab. It depends on how a persons immune system reacts. How long does the allergic reaction to poison ivy last. If you know what you're allergic to, just read the ingredients on the package.
Stopped taking the medication due to bad outbreak of hives - raised itchy bumps all over my back and tummy. I'm still experiencing outbreaks though. Certain people are hypersensitive to shrimps at such intensity that even mere touch may produce allergy symptoms.