Shrimp Allergy: An Overview

Shrimps belong to a group of shellfish called crustaceans. 

Shrimp allergy is one of the most common food allergies in children and adults.

Shrimp allergy develops when the immune system recognizes certain proteins in shrimps as harmful substances and reacts to them. 

This reaction triggers the symptoms of shrimp allergy.

The body’s immune reaction is triggered when the IgE antibodies bind to the proteins in shellfish protein. 

There are different proteins (allergens) in shrimp that can cause an allergy.

It is also important to note that an allergy to shellfish like shrimp is confused with an allergy to components like iodine or microbes present in these animals. 

Many people who are intolerant to shrimp can confuse this condition with an allergy to the food.

Symptoms of Shrimp Allergy

Symptoms of shrimp allergy vary from mild to severe and can affect different parts of the body, including the skin, respiratory system, digestive system, and heart.

Common symptoms of shrimp allergy are:

• Hives
• Itching
• Tingling sensation around the lips, tongue, or throat
• Flaring up of eczema
• Coughing or sneezing
• Breathing trouble
• Nasal congestion
• Dizziness
• Pale skin coloring
• Digestive issues like nausea, vomiting, digestion, or diarrhea

Shrimp consumption can lead to a severe, potentially fatal allergic reaction called anaphylaxis in some people.

According to a study, in adults with shrimp allergy, the rate of anaphylaxis to shrimp was 42%.

Can You Develop Allergies To Shrimp Later In Life?

While most people discover their food allergies in their childhood, you can develop an allergy to shrimp as you get older.

Studies estimate that around 60% of people who develop this food allergy get their first reaction as adults. 

This may be because not many children eat shellfish.

Do All Types of Shellfish Cause The Same Reaction?

Shrimp is one of the many shellfish varieties consumed by us. 

However, just because you are allergic to shrimp does not mean you will be allergic to all types of shellfish and fish.

It is, however, essential to note that people who may be allergic to crustaceans like shrimp may be allergic to mollusks too. 

Speak to your healthcare provider to understand more about your shrimp allergy.

How Common is Shrimp Allergy?

Shrimp allergy is a relatively common food allergy and affects around 2% of the American population.

Genetics of Shrimp Allergy - The HLA Gene Family

The exact reason why some people are allergic to shrimp is unknown. However, genetics may have a role to play in the development of shrimp allergy.

The human Leucocyte Antigen (HLA) system is a complex set of genes present on chromosome 6. 

These genes give instructions to produce proteins to regulate the immune system.

The HLA system of genes has three classes – HLA-DR, HLA-DQ, and HLA-DP.

rs74995702 is a single nucleotide polymorphism or SNP in the HLA-DR/DQ gene region. 

According to a genome-wide association study, people with the G allele of this SNP are at a greater risk of developing shrimp allergy than those with the A allele.

Risk Factors for Shrimp Allergy

Those with a family history of any allergies are at a higher risk for shrimp allergy.

Among adults, this allergy is more common in women and among children, in boys.

People prone to shrimp allergy who come in close contact with shrimp during cooking, steaming, or frying can develop an allergic reaction.

Fishermen, cooks, shell grinders, workers who process shellfish, and even restaurant staff can develop shrimp allergies due to repeated exposure to it.

Shrimp Allergy: Treatment and Prevention 

• The first line of treatment for shrimp allergy is epinephrine or adrenaline. 
• If you are allergic to shrimp, your doctor will advise you to keep an epinephrine auto-injector with you at all times and teach you how to use it.
• Immediate administration of epinephrine on exposure to shrimp can prevent a fatal anaphylactic reaction.
• If you have mild to moderate shrimp allergy, your doctor may prescribe antihistamines and corticosteroids.
• The best way to prevent shrimp allergies is to avoid them in any form. 
• Your doctor may also recommend that you undergo further allergy tests to determine other shellfish that you may be allergic to.

• To prevent an allergic episode to shrimp, you must check the food labels carefully and take care while eating at restaurants. 
• Inform your waiter about your allergy before ordering a dish at a diner or restaurant.
• Some foods that you must avoid are fish stock, seafood flavorings, sushi, etc. 
• Though some food allergies disappear as you grow older, we can’t say the same about shrimp allergies yet.

Summary

1. Shrimp allergy, affecting ~2% of the US adult population is a common food allergy in adults and children.
2. Allergic reactions to shrimp manifest as hives, itching, coughing and wheezing, and eczema.
3. Those who are allergic to shrimp may have allergies to other shellfish as well.
4. The HLA gene family that is involved in regulating immune responses plays a role in the risk for shrimp allergy.
5. Epinephrine injections, antihistamines, and corticosteroids are common treatment options for shrimp allergy.
6. Checking food labels, informing about your allergy at restaurants, and avoiding certain foods can help prevent allergic reactions. 

References:

• https://my.clevelandclinic.org/health/diseases/11319-allergies-shellfish 
• https://www.mayoclinic.org/diseases-conditions/shellfish-allergy/symptoms-causes/syc-20377503 
• https://www.ncbi.nlm.nih.gov/books/NBK448089/ 
• https://pubmed.ncbi.nlm.nih.gov/26108073/

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