Allergic to seafood and shellfish—Alternatives or remedies?

Dear Reader, 

A frustrating part of developing an allergy as an adult, rather than as a child, is knowing what you’re missing! Shellfish allergies are very common in the United States. Reactions occur when a person’s Immunoglobin E (IgE) antibodies—antibodies produced by the immune system—bond with the proteins in consumed shellfish, leading to symptoms such as hives, itchiness, or respiratory problems. In severe cases, shellfish allergies can trigger anaphylaxis—a potentially fatal reaction causing breathing to be blocked. If you suspect that you may be allergic to shellfish or seafood because you have historically experienced these symptoms, it’s recommended that you avoid eating these foods and any products that contain them. That being said, allergen immunotherapy, which involves building up exposure to allergens little by little, may also be an option for you to explore (more on this in a bit). 

Generally, allergies tend to present while in childhood and in some cases go away with age. However, there are some allergies—including ones to seafood—that are actually more common in adults and usually stick around indefinitely. For example, one study showed that almost three percent of adults, compared to less than one percent of children had a seafood allergy. In some cases, adults may even have more severe reactions to allergens than ones experienced by children. In general, adult-onset allergies are believed to occur due to cross-reactions, meaning that an allergy to one substance (like pollen) may eventually lead to an allergy to something with similar proteins (because the immune system hones in on them). Shrimp, crab, crawfish, lobster, squid, oyster, snails, mussels, clams, and scallops share an allergen called tropomyosin, which is also common in cockroaches and dust mites. Studies have shown that a person who is allergic to one of these has a 75 percent chance of also being allergic to another from that same group. Being allergic to dust mites, for example, may later lead to an allergic reaction to shellfish. Other factors such as asthma, exercise, alcohol, and certain medications can increase sensitivity to various allergens. 

It’s important to note that having an intolerance to shellfish or seafood can be very different than having a full-blown allergy. A person with an allergy to seafood or shellfish will likely experience an allergic reaction upon ingestion; the reactions can range from mild to severe, including fatality. Symptoms can include swollen and itchy lips, mouth, and pharynx (inside the throat). Those who simply have an intolerance to seafood or shellfish, on the other hand, may feel sick after eating it but won’t go into anaphylactic shock. Additional symptoms of an intolerance could include congestion, coughing, stomach pain, dizziness, or wheezing during or after eating it. 

Whether you have an allergy or intolerance, it’s a good idea to steer clear of these sea critters.  By law in the United States, a product that contains shellfish must have a clear label on the package that says so. However, seafood or shellfish traces may be found in many products that would not seem suspicious, including but not limited to: 

• “Meatless” hot dogs, sausages, and pizza toppings 
• Worcestershire sauce 
• Some Caesar salad dressings 
• Vitamins 
• Soaps and cosmetics 
• Insecticides 
• Sauces and seasonings 

Additionally, some restaurants may use the same oil to cook seafood and non-seafood dishes, which can lead to cross-contamination. You may consider asking your server how food is prepared and if there is a possibility that seafood or shellfish may encounter your plate. 

In terms of treatments or alternatives, allergen immunotherapy has been shown to be beneficial in some cases; however, overall efficacy is still mixed. Specifically, the use of allergen immunotherapy has shown potential to treat shrimp allergies in some trials. If you are someone with mild symptoms, you may talk with your health care provider about using antihistamines as a way to find some relief. Some studies have also suggested that probiotics might have the ability to restore tolerance for shrimp—especially when you take them in addition to undergoing immunotherapy. 

Before you pursue these treatments, it might be helpful to confirm (if you haven’t already) that what you’re experiencing is indeed an allergic reaction. A health care provider can conduct a skin prick test and observe how your body reacts to a small amount of an allergen to determine if it’s an allergy or not. Blood tests can also be used to measure the amount of IgE antibodies that are detectible in your body in response to shellfish and seafood. 

When it comes to getting rid of a shellfish or seafood allergy entirely, there seems to be no immediate cure yet. However, there is research on vaccines to help reduce the symptoms for those with allergies. In fact, some vaccine trials have shown success at reducing the severity of shrimp allergies. However, until this treatment becomes available, it may be a good idea to avoid seafood and shellfish entirely to prevent a potential reaction. Because the meat of many crustaceans is hard to replicate (in both texture and taste), non-seafood alternatives are hard to come by. Many vegetarian alternatives may also have seafood or shellfish byproducts or flavorings, so it’s advised to avoid them as well. That being said, there are some vegan versions of shrimp and shellfish available that claim to contain no animal products or byproducts but it’s unclear whether this is in fact true. That said, before heading to the supermarket, it might be good to speak with your health care provider about whether these options would be safe for you. They can help you navigate your new dietary outlook and hopefully determine some safe and tasty alternatives.