Shellfish allergy is one of the most common food allergies and usually persists throughout life. It arises as a response of the immune system to proteins present in crustaceans and mollusks. Reactions can be generalized or specific to certain types of shellfish, presenting in mild and severe forms.

Shellfish cause many allergies due to a combination of biological and environmental factors. First, the proteins present in crustaceans and mollusks—such as tropomyosin—are highly immunogenic: in some people the immune system mistakenly identifies them as dangerous and generates antibodies (IgE) that trigger reactions upon contact, ingestion or even inhalation of particles.

This exaggerated response causes subsequent exposure to produce symptoms ranging from itching and hives to breathing difficulties or anaphylaxis. Additionally, the prevalence of shellfish allergy increases with age and diet. Genetics also plays a role: certain family variants predispose you to developing food allergies in general.

Environmental factors—such as early infections, changes in the intestinal microbiota due to antibiotics or pollution—can alter the development of the immune system and favor the appearance of sensitivities.

Another important point is the frequency and form of processing. Seafood is common ingredients in prepared foods and restaurants; Cross-handling with other foods or the presence of allergens in cooking aerosols facilitates unintentional exposures.

Symptoms and types of shellfish

According to the Mayo Clinic, the most common symptoms of shellfish allergies include hives, nasal congestion, swelling, and breathing difficulties. Anaphylaxis is the most serious reaction and requires immediate medical attention, manifesting with symptoms such as inflammation of the throat and a significant drop in blood pressure.

On the other hand, there are differences between types of shellfish: allergies to crustaceans (shrimp, lobster, crab) are more common and persistent in adults, while allergies to fish and some mollusks can behave differently. The only sure way to prevent reactions is to avoid the offending food and carry, if directed by your doctor, an emergency epinephrine autoinjector.

Causes and risk factors

The allergy is the result of an exaggerated reaction of the immune system to the proteins in shellfish. Factors such as family history and prevalence in adults, especially women, increase the risk of developing this condition.

The only effective way to avoid allergic reactions is complete abstinence from shellfish. People should be proactive in reading labels and avoiding cross-contamination, as well as be prepared for emergencies with injectable epinephrine.

contaminated seafood

402 outbreaks of food illnesses have been identified in the United States caused by marine toxins over 23 years, resulting in 1,280 patients, 96 hospitalizations and one death, notes the Weekly Morbidity and Mortality Report.

Researchers at the Centers for Disease Control and Prevention (CDC) and the Oak Ridge Institute have highlighted the magnitude and severity of these outbreaks.

It is claimed that storing fish at uncontrolled temperatures can trigger the production of histamine, which can cause allergic reactions in people, and scombroid toxins produced by bacteria with the highly active enzyme histidine carboxylase. Other marine toxins can be produced by algae and accumulate in fish and shellfish through the food chain, occur naturally in fish species or come from unknown sources, according to the Center for Infectious Disease Research and Policy (CIDRAP) portal, at the University of Minnesota.