It is possible for individuals who are allergic to one type of seafood to be able to eat other types of seafood without an allergic reaction. However, people with allergies to one type of seafood are often sensitive to other types of seafood in the same class. For example, people who are allergic to one type of shellfish (e.g., lobster, crabs) are usually sensitive to most other types of shellfish. In general, people with shellfish allergies can usually eat fish safely, while people with fish allergies can usually consume shellfish. However, people with seafood allergies should consult their physician before trying to eat any type of seafood. Only a physician can safely determine what types of food are safe to eat.

Though cod is the most common type of fish allergy reported, there are many types of seafood allergies (Note: This is not a complete list):

In general, children are more likely to suffer from allergies to cod and salmon, while allergies to shrimp, crab and lobster are more common in adults. This is most likely due to dietary differences among these age groups.

People with seafood allergies must also be careful to avoid the many types of foods that contain fish or shellfish products. Even a trace amount of seafood protein can trigger an allergic reaction. Some common products that frequently contain seafood components are:

• Worcestershire sauce. Contains fish (anchovies).
  
  
• Steak sauce. May contain seafood.
  
  
• Caesar salad. Often contains anchovies either on the salad or in the dressing.
  
  
• Caviar. Made of fish eggs.
  
  
• Marinara sauce. Sometimes contains anchovies.
  
  
• Roe. Unfertilized fish eggs.
  
  
• Surimi (a type of imitation crab popular in some Asian restaurants). Contains fish proteins for added flavoring.
  
  
• Hot dogs, bologna and ham. Can contain fish flavoring (surimi).
  
  
• Pizza toppings. Sometimes contains anchovies.
  
  
• Fried rice and spring rolls. May contain shrimp.
  
  
• Caponata (a Sicilian relish). Can contain anchovies.
  
  
• Coffee and wine. Fish skin is used to clarify some of these drinks.
  
  
• Gelatin-based foods (e.g., marshmallows). May contain seafood.
  
  
• Pet fish food. This dried substance is made of brine shrimp and other seafood. It can easily become airborne and, if inhaled, may trigger symptoms in some people with seafood allergies.
  
  
• Pet food. Dog and cat food may contain seafood.

Allergic individuals should also carefully read the labels of medication, cosmetics, creams and ointments, as some of these products contain fish and shellfish.  

Cooking seafood with other types of food often leads to seafood protein contamination of normally safe foods. For instance, restaurants use vats of oil to fry their foods – often using the same vats to fry shrimp, chicken, French fries and more. Grills and spatulas at restaurants can also become contaminated if they are not cleaned properly after cooking seafood.

Some individuals can be sensitive to the airborne fumes produced by cooking fish. These people can also have an allergic reaction triggered by simply walking through a fish market. Individuals who are this sensitive should be very careful about dining in restaurants or unfamiliar places. Sensitive individuals can also receive an allergic reaction from skin contact with fish and should avoid handling seafood.