Crustacean Allergy: Symptoms, Risks, and Precautions

Crustacean allergy is a common food allergy that affects many individuals worldwide. It is caused by an immune response to certain proteins found in crustaceans, such as shrimp, lobster, and crab. While the symptoms can range from mild to severe, crustacean allergies can be life-threatening in some cases, particularly when anaphylaxis occurs. Understanding the symptoms, hidden sources of crustaceans, and necessary precautions is critical for those affected.

Common Symptoms of Crustacean Allergy

The symptoms of a crustacean allergy can vary depending on the individual and the severity of the reaction. Common symptoms include:

  • Skin Reactions: Hives, redness, or swelling of the skin are common reactions. Some people may also experience eczema or itchiness.
  • Gastrointestinal Symptoms: Nausea, vomiting, abdominal cramps, and diarrhea can occur shortly after consuming crustaceans.
  • Respiratory Issues: Wheezing, coughing, shortness of breath, or even a sore throat may arise as a result of the allergic reaction.
  • Anaphylaxis: In severe cases, a person may experience difficulty breathing, dizziness, a drop in blood pressure, or loss of consciousness, all of which require immediate medical attention. Anaphylaxis is a life-threatening reaction that can occur rapidly after exposure to crustaceans (NHS).

Foods Containing Crustaceans That You Might Not Expect

Crustaceans are often found in familiar foods like shrimp cocktails or lobster rolls, but they can also be hidden in other dishes or food products. Some less obvious sources of crustaceans include:

  • Surimi (Imitation Crab Meat): Often used in sushi, salads, and seafood sticks, surimi is made from fish and crustacean proteins, making it a potential hidden allergen.
  • Sauces and Seasonings: Some pre-made sauces, such as fish sauce or certain Asian sauces, may contain crustaceans like shrimp paste or crab extract.
  • Processed Foods: Some processed foods, including snack foods, soups, and even frozen meals, can contain crustaceans as an ingredient or due to cross-contamination during processing.
  • Non-Food Products: In some cases, crustaceans may also appear in non-food items, such as certain beauty products or pet foods, due to the inclusion of shellfish-based ingredients.

To ensure safety, it is crucial to check labels carefully, especially in pre-packaged or processed foods.

Diagnosis and Severity

Diagnosing a crustacean allergy typically involves a combination of medical history review, skin prick tests, or blood tests that measure the body's immune response to crustacean proteins. If anaphylaxis is suspected, a doctor may recommend carrying an epinephrine auto-injector (EpiPen) to treat severe reactions. Testing for allergens is essential to confirm whether crustaceans are the cause of the allergic symptoms.

Severity

The severity of a crustacean allergy can vary from mild to life-threatening. In some individuals, even a small exposure can trigger a serious reaction. The most severe form of a reaction is anaphylaxis, which requires immediate medical intervention (NHS). The response to crustaceans may worsen over time if not managed properly, making it essential to take precautions.

Treatment and Management

The primary treatment for a crustacean allergy is to avoid exposure to crustaceans altogether. This includes avoiding obvious sources such as shrimp and lobster, as well as more hidden sources like surimi or seafood-based sauces.

Emergency Response

For individuals with a known crustacean allergy, carrying an epinephrine auto-injector is crucial in case of accidental exposure. Epinephrine (adrenaline) can quickly reverse severe allergic reactions, including anaphylaxis, but it is not a cure. After using an epinephrine injection, the individual should seek immediate medical attention.

Desensitisation (Oral Immunotherapy)

Currently, there is no widely available treatment to cure a crustacean allergy. However, researchers are exploring options like oral immunotherapy, where a person is gradually exposed to increasing amounts of the allergen in a controlled setting to build tolerance. This is an area of ongoing research.

Who Is at Higher Risk?

Certain individuals may be more likely to develop a crustacean allergy:

  • Children: Food allergies, including crustacean allergies, are more common in children, although many outgrow these allergies with age.
  • Family History of Allergies: Individuals with a family history of allergies (especially food allergies) are at higher risk of developing a crustacean allergy.
  • Other Allergies: People who already have other allergies, such as those to pollen or other food allergens, may be more likely to develop a shellfish allergy.

Conclusion

Crustacean allergy is a serious condition that requires careful management. The severity of symptoms can range from mild skin reactions to life-threatening anaphylaxis, and even small amounts of crustaceans can trigger a reaction in sensitive individuals. Diagnosis is key, and avoiding crustaceans and products containing them is the best way to manage the allergy. People with crustacean allergies should always be prepared with an epinephrine auto-injector and work closely with healthcare providers to manage the condition effectively.

Resources:

  1. NHS: Food Allergy
  2. AllergyUK Shellfish Factsheet
  3. Mayo Clinic
Note: This article is intended for informational purposes and should not replace professional medical advice.