What Is A Shellfish Allergy? Symptoms And Causes

When the immune system of your body gives an abnormal response to proteins present in specific marine animals, it is called shellfish allergy. Marine animals in the category of shellfish are squid, shrimp, scallops, oysters, lobster, crab, and others.

Some people who have an allergy to shellfish give reactions to all types of shellfish while others respond to certain types. The reaction may have mild symptoms to severe ones. Symptoms include a stuffy nose and hives. Reaction to shellfish can even prove life-threatening for some individuals.

Talk to your doctor if you think you have the symptoms of shellfish allergy. The test may help you to be diagnosed with an allergy. In this way, you can take a few steps in order to avoid such reactions in the future.


Signs of shellfish allergy usually appear within minutes to one hour after eating it. These symptoms may include eczema (atopic dermatitis), hives or itching, and swelling of the tongue, face, lips, or throat. You can also have swelling on other body parts if you have a shellfish allergy.

Some people with a shellfish allergy may experience fainting, dizziness, diarrhea, vomiting, abdominal pain, or lightheadedness. Allergies can induce a life-threatening reaction that is called anaphylaxis. 

It is a medical emergency in which individuals need treatment with an injection of epinephrine. A person with a shellfish allergy may have to visit the emergency room during anaphylaxis. Following are the symptoms of anaphylaxis.

  • A lump in the area of the throat or a swollen throat
  • Shock with an intense drop in the blood pressure 
  • Loss of consciousness or dizziness

If you develop the symptoms of anaphylaxis, go to seek emergency treatment. Never ignore this condition because it can cause more complications or irreversible consequences. See an allergy specialist if you suspect that you have the symptoms of food allergy after eating.


An immune system overreaction is responsible for all food allergies. Your immune system identifies a protein present in the shellfish as harmful mistakenly during a shellfish allergy. It triggers the antibodies production to the protein of shellfish.

Your immune system may order to release histamine and other chemicals next time when you come in contact with certain allergens. These chemicals induce the symptoms of allergy.

Types Of shellfish 

There are two types of shellfish. Different proteins are present in each type. These types are:

  • Crustaceans: It includes prawn, crayfish, crabs, shrimp, and lobster.
  • Mollusks: It includes scallops, squid, clams, snails, and oysters.

Risk Factors

If you have a family history of any type of allergies, you are vulnerable to developing the symptoms of a  shellfish allergy. People of any age can develop the symptoms of shellfish allergy. But it commonly occurs in adults. 

Among adults, females commonly experience shellfish allergy symptoms. When we talk about children, boys experience the symptoms of shellfish allergy more as compared to girls.


Shellfish allergy can cause anaphylaxis in severe cases. It is a dangerous reaction to an allergy that causes shock, lightheadedness, rapid pulse, and swollen throat. The condition of anaphylaxis can cause life-threatening consequences in some cases.

If you have asthma with a shellfish allergy and a family history of anaphylaxis that is food-induced, you are at risk of getting anaphylaxis. Moreover, you can have this condition if you get allergic reactions after eating a shellfish in very small amounts.


If you have the problem of shellfish allergy, the only solution to avoid it is avoiding all the products that include shellfish. Even you should avoid trace amounts of shellfish because it can lead to a severe allergic reaction.

Avoiding Shellfish 

  • Be Careful When Dining Out: Always check that the oil, pan, and utensils used for shellfish are not used to prepare certain other foods. It creates cross-contamination. Avoid eating at restaurants that offer seafood if the risk of cross-contamination is high.
  • Read Labels: Cross-contamination can occur in certain stores. The reason is other foods are sometimes displayed or processed near shellfish. It also happens during the process of manufacturing. You have to carefully read the food labels. Shellfish may be a hidden ingredient.
  • Maintain Your Distance: We suggest you to avoid the places completely where shellfish are processed or prepared. Some people can have allergic reactions when they touch or inhale steam from the cooking of shellfish.

Visit your doctor on regular basis in case of having a severe shellfish allergy. Early treatment can save you from preventing worse conditions.