What are the other Names for this Condition? (Also known as/Synonyms)

• Allergy to Seafood

What is Seafood Allergy? (Definition/Background Information)

• Seafood Allergy is a condition that occurs when certain seafood causes an allergic reaction in individuals, who consume them.
• The seafood may include all marine animals, such as tuna, cod, salmon, shrimp, lobster, crab, tilapia, catfish, octopus, and other fish.
• There are numerous signs of an allergic reaction to seafood. These include wheezing, runny nose, hives, sneezing, and asthma. Such allergies are generally diagnosed using either a RAST test, or a skin-prick test.
• Anti-allergic medications form the first line of treatment for mild Seafood Allergies. However, in the case of a severe allergic reaction that is an emergency situation, epinephrine injection via an EpiPen is recommended.
• Awareness of such allergies and avoiding the specific seafood that causes the allergy is the best form of treatment and prevention. Presently, in many countries, due to labeling and consumer protection laws, foods with major seafood allergens have labels that indicate their content.

Seafood Allergy is usually grouped into 2 types:

Fish Allergy:

• Approximately 1 in 250 individuals have a Fish Allergy
• This group consists of both “scaly” and “bony” fish
• Examples include cod, herring, trout, salmon, and tuna

Shellfish Allergy:

• About 1 in 50 individuals are reported to have some form of Shellfish Allergy
• Those who are allergic to one type of shellfish are usually allergic to other types too
• There are two main types of shellfish:
  • Crustaceans: Common examples are shrimp, crab, and lobster
  • Mollusks: Common examples are clams, oysters, and scallops
• Allergic reactions to crustaceans are usually much more severe, than allergic reactions to mollusks 

Who gets Seafood Allergy? (Age and Sex Distribution)

• Millions are believed to be affected by Seafood Allergies worldwide, each year
• Seafood Allergies usually occur in older children and adults
• This type of allergy is more prevalent in women than men. However, in older children, Seafood Allergies are more common in boys than girls
• African Americans have the highest incidence of Seafood Allergies, compared to other racial/ethnic groups

What are the Risk Factors for Seafood Allergy? (Predisposing Factors)

The risk factors of Seafood Allergies include:

• Consuming the particular type of seafood (either fish or shellfish) that one is allergic to
• Any family history of such seafood allergy may be a risk factor

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider. 

What are the Causes of Seafood Allergy? (Etiology)

• An allergic reaction occurs in an individual with Seafood Allergy, because the immune system recognizes certain proteins in seafood as being dangerous and harmful to the body. This results in the production of antibodies, specifically immunoglobulin E (IgE)
• The next time the individual comes into contact with the same protein, the antibodies that are circulating in blood causes an antibody-antigen reaction
• This results in the production of histamine and other chemical messengers, which cause the symptoms seen during an allergic reaction
• In some cases, a severe allergic reaction termed as anaphylaxis may occur, which is a medical emergency that requires immediate medical attention 

What are the Signs and Symptoms of Seafood Allergy?

The symptoms may start to appear within a few minutes, to a couple of hours, after the individual has consumed the particular type of seafood they are allergic to. The symptoms of Seafood Allergies are also common to other types of food allergies. In some, the symptoms are mild, while in others they are severe. A severe allergic reaction is a medical emergency. 

The signs and symptoms may include:

• Itching
• Urticaria (hives)
• Atopic dermatitis (eczema)
• Swelling of mouth and throat, especially if the seafood is consumed
• Coughing, sneezing
• Shortness of breath (trouble breathing), wheezing, asthma
• Runny or stuffy nose
• Nausea, diarrhea, vomiting
• Dizziness and fainting 

While some of the general symptoms listed above can be severe, the most severe symptom caused by seafood and other food allergies is anaphylaxis.

• Anaphylaxis (sometimes called an anaphylactic shock) is a life-threatening, whole-body allergic reaction
• During anaphylaxis, tissues in various body parts release histamine and other messenger chemicals, which causes swelling of the throat and other symptoms
• Swelling of the throat is especially dangerous as this can cause shortness of breath. If the swelling is not reduced soon, then there is a possibility that the individual could die from a lack of sufficient oxygen 

How is Seafood Allergy Diagnosed?

If there is a history of allergic reaction in an individual that occurs after eating or coming into contact with seafood, then further tests will be conducted for a full diagnosis.

The two tests that are usually conducted to diagnose a Seafood Allergy are:

Radioallergosorbent test (RAST):

• This test looks for the presence of immunoglobulin E (IgE); IgE is produced by the immune system during an allergic reaction
• IgE antibodies are specific: Individuals with Seafood Allergies will have antibodies specific to the seafood type the individual is allergic to

Skin-prick test:

• For this test, small amounts of certain substances are injected right underneath the skin (forearm, upper arm, or back)
• After 15-20 minutes, if the spot where the chemical was injected swells, or if there is redness noticed, then this indicates that the individual may be allergic to the substance 

A diagnosis of Seafood Allergy must be made carefully, because if an individual has an adverse reaction after consuming a seafood type, it may not automatically indicate that the individual has an allergic reaction. Other conditions, like food poisoning or an infection, which can cause some of the same symptoms seen with Seafood Allergies, may have to be eliminated, before arriving at a definitive diagnosis. 

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis. 

What are the possible Complications of Seafood Allergy?

• The possible complications of Seafood Allergies are associated with the allergic reaction itself. It will depend on the severity of the reaction that the individual has undergone
• In severe reactions, a tracheostomy may have to be performed during an emergency situation 

How is Seafood Allergy Treated?

The best form of treatment of Seafood Allergy is by preventing such an allergic episode; by avoiding consumption of the specific seafood that one is allergic to.

• If an allergic reaction does occur, the physician will use suitable treatment and anti-allergic medication, based on the symptoms that are present
• In the case of anaphylaxis, an epinephrine auto-injector (like EpiPen) is immediately administered 

How can Seafood Allergy be Prevented?

• The best way to prevent Seafood Allergy is to avoid contact with the seafood that an individual is allergic to
• Often times, proteins from seafood (that can cause the allergy) may be present in air via steam (from the cooked dish). Therefore, individuals with Seafood Allergies should avoid restaurants that serve seafood, or should avoid areas where seafood is being cooked 

What is the Prognosis of Seafood Allergy? (Outcomes/Resolutions)

• Most individuals with Seafood Allergies, have it for the rest of their lives
• However, allergic reactions may be prevented by avoiding seafood (fish and shellfish). The individual may not feel most of the adverse effects of the condition, if the allergic reactions can be minimized
• In some cases, the allergic reaction may be severe, causing anaphylaxis. This is a medical emergency that can lead to a respiratory failure. It requires an immediate treatment of the condition. In such cases, the prognosis is guarded and it depends on whether immediate medical assistance is provided 

Additional and Relevant Useful Information for Seafood Allergy:

In US and many countries, due to the ‘Food Allergen Labeling and Consumer Protection Act’ (or similarly worded acts), packaged foods must be labeled, if the product contains major food allergens, including seafood. The label starts with the word “Contains” and then lists the various food allergens present in the food product.