Shellfish Allergies: Symptoms and Treatments

What are shellfish allergies?

Although most major food allergies begin in childhood, one allergy in particular stands apart: shellfish. An allergy to shellfish may develop any time during a person’s life, but tends to present in adulthood. It can be caused by foods that you’ve eaten before with no issues.

Along with fish, shellfish allergies are the most common adult-onset food allergies. It’s estimated that more than 6.5 million American adults have allergies to one or both, according to Food Allergy Research & Education (FARE).

What foods should I avoid if I have a shellfish allergy?

There are two kinds of shellfish, crustaceans and mollusks. Here are a few examples of crustaceans to watch out for if you’re allergic:

  • shrimp
  • crab
  • prawn
  • crayfish
  • lobster

Mollusks include:

  • clams
  • mussels
  • oysters
  • squid
  • cuttlefish
  • octopus
  • snails
  • scallops

Most people who are allergic to one type of shellfish are also allergic to the other type. There’s a chance you may be able to eat some varieties. However, doctors usually recommend that people with shellfish allergies avoid all varieties to be safe.

A shellfish allergy is different from other allergies in other ways, as well. For example, allergic reactions to shellfish are unpredictable, sometimes occurring long after a person has consumed the allergen and has shown no other symptoms. Allergic reactions to shellfish also often become more severe with each exposure.