How To Diagnose Shellfish Allergy
If you suspect a shellfish allergy, make an appointment with your doctoreven when symptoms are mild. Since a shellfish allergy can worsen over time, you shouldnt self-diagnose. Your regular doctor may refer you to an allergist for testing.
Your doctor may complete a physical examination, and then ask about your symptoms and the circumstances surrounding your allergic reaction. To make an accurate diagnosis, your doctor may suggest two tests a skin prick test or a blood test. Testing also helps distinguish a food allergy from conditions with similar symptoms, such as seafood poisoning.
1. Skin prick test. This test examines your bodys response to a suspected allergen. Your doctor pricks your skin with a small amount of the shellfish protein, usually on the forearm or the back of your hand. Your doctor watches your skin to see if hives or raised bumps develop at the prick site. If bumps develop, this can indicate a shellfish allergy. Results are typically available within 15 to 30 minutes.
2. Blood test. This test evaluates how your immune system responds to the shellfish protein, and checks the level of certain antibodies in your bloodstream.
What Causes Allergies Later In Life
Just like childhood allergies, we do not completely understand why some people develop allergies and others dont. We do know there are complex genetic and environmental factors involved. Scientists have proposed theories about why allergies occur, including the hygiene hypothesis that attributes allergic disease in part to the use of antimicrobials and the high standard of cleanliness in modern societies.
Adults can also present with new-onset environmental allergies. In some cases, the patient may have had a tendency to develop allergies all along, but their environment changed, putting them in more contact with the triggering allergen .
Prevalence Of Seafood Allergies & Sub
Allergies to seafood are the most commonly reported allergy for adults and are among the most common for young children. Seafood allergies affect about 1-3% of the general population, with allergy to shellfish specifically being the most common and tending to cause more severe reactions and emergency department visits. Seafood allergy can be split into two categories: fish allergy and shellfish allergy. Fish allergy can include allergies to species like the following: salmon, tuna, and cod. Shellfish allergy is further broken down into crustacean allergy and mollusk allergy . Many individuals who are allergic to one type of shellfish are also allergic to the other. Crustacean allergy is more common than mollusk allergy. Geographic distribution and varying dietary patterns also influence the prevalence of shellfish allergies for example, shellfish allergy is considered more common in Asian countries, where shellfish is more often consumed, than in, for instance, the US.
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Are Allergies Worse In Childhood Or Adulthood
Per the American College of Allergy, Asthma & Immunology and 2013 data, 28 million kids across the United States have allergies. As many as 50 million adults may get reactions to allergens as well.
While more adults have allergies in the United States than children, is there an age group that has it worse? Research that appeared in a 2012 article at MassGeneral Hospital for Children in Massachusetts suggests that adults may be the most at risk for intense, serious symptoms. Adult behaviors such as taking certain medications and drinking alcohol may increase risk for severe anaphylaxis. Exercise and having asthma can also increase reaction severity. Of course, young children who cannot communicate symptoms can also have severe reactions which go unnoticed and progress to dangerous levels.
A severe allergic reaction, which can be triggered by foods or venom , is called anaphylaxis. This is a life-threatening emergency condition in which the patient goes into shock, cannot breathe, and may have vomiting, nausea, and skin rashes. Anaphylaxis can occur instantaneously or sometimes minutes after eating an allergen or being stung. Epinephrine can control cases of anaphylaxis that are caught immediately. The longer the patient goes without treatment, the greater the likelihood that death can occur. For this reason patients with a history of severe anaphylaxis are encouraged to always have an in date epinephrine injector available.
What Causes Shellfish Allergy
Shellfish are classified as either crustaceans or molluscs. Below are examples of each category:
Crustaceans
- snails
- squid
A protein called tropomyosin found in crustaceans and molluscs triggers a reaction from the immune system of individuals who are allergic to shellfish. This allergic response involves the release of a chemical known as histamine to fight off what your body believes to be a harmful foreign substance that has entered your system. This chemical triggers the symptoms of your shellfish allergy.
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Managing Shellfish Allergies In Children
Because shellfish allergy reactions, like other food allergy symptoms, can develop when a child is not with his or her parents, parents need to make sure that their childs school, day care or other program has a written emergency action plan with instructions on preventing, recognizing and managing these episodes in class and during activities such as sporting events and field trips.
If your child has been prescribed an auto-injector, be sure that you and those responsible for supervising your child understand how to use it.
This page was reviewed for accuracy 2/13/2019.
Shellfish Allergy Testing And Diagnosis
Shellfish allergy can be particularly challenging to diagnose. Although the signs of an allergic reaction tend to be more severe than other food allergies, the resulting symptoms can mirror those of other conditions.
For example, histamine toxicity can present in similar ways to shellfish allergy. Some fish contain high levels of histidine, which the body converts to histamine, creating a response that mimics an allergic reaction. Histamine toxicity most commonly occurs in fish that has not been refrigerated properly or in fish that has spoiled. Other forms of shellfish-related food poisoning that may seem like an allergy include paralytic shellfish poisoning, neurotoxic shellfish poisoning, and amnesic shellfish poisoning.
Oral allergy syndrome can also mimic shellfish allergy. This type of food allergy is generally considered to be mild, and occurs when the mouth and throat come into contact with raw vegetables or fruits. OAS shares symptoms with shellfish allergy, such as itchiness of the mouth and throat and swelling in the mouth , which can make it difficult to separate the two.
The gold standard of testing encompasses three ways to clinically determine whether someone has a true shellfish allergy or is suffering from shellfish toxicity or poisoning.
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Fish And Shellfish Allergies Can Appear Later In Life
Q: I’m in my mid-30s and I’ve never had food allergies. But lately I’ve been getting symptoms that seem like an allergic reaction after I eat shellfish — itchiness and swollen lips. I thought food allergies appeared in childhood or not at all, but I’m starting to question this. Is it possible for me to develop a food allergy as an adult?
Are You At Risk
If you arent currently experiencing any new-found allergy symptoms, how do you know if you are at risk? Allergies are most common in adults with genetic susceptibility or family history of allergies. Everyone has a different personal vulnerability to allergies, which is why some may develop sensitivities and others will never experience any symptoms. Environmental exposures to certain allergens can also put you at risk of developing allergies. For example, several years of exposure to allergens can cause you to develop skin or lung sensitivities. As you age, you may lose tolerance to chemicals and ingredients in shampoo, perfumes or makeup, which can lead to allergic reactions on your skin.
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Suddenly Allergic To Shellfish Heres How To Cope
Unlike most food allergies that develop during childhood, a shellfish allergy typically emerges during the teenage or adult years. You may have eaten shellfish without any issues for years and then suddenly experience allergic reactions after consuming crustaceans or molluscs.
Before we share with you the ways to cope with shellfish allergy, let us first identify which foods qualify as shellfish and which symptoms point to a shellfish allergic reaction.
Severe Allergic Reaction Anaphylaxis
A severe allergic reaction is life threatening.Symptoms of a severe allergic reaction include:
- difficult or noisy breathing
- persistent dizziness or collapse
- paleness and floppiness in young children.
If you, or a child in your care, have a severe allergic reaction , call triple zero for an ambulance. Do not stand or walk. Administer adrenaline via autoinjector , if available.
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Exercise As Contributing Factor
Exercise can be a contributing factor to an allergic food response. There is a condition called food-dependent, exercise-induced anaphylaxis. For people with this condition, exercise alone is not sufficient, nor consumption of a food to which they are mildly allergic sufficient, but when the food in question is consumed within a few hours before high intensity exercise, the result can be anaphylaxis. Shellfish are specifically mentioned as a causative food. One theory is that exercise is stimulating the release of mediators such as histamine from IgE-activated mast cells. Two of the reviews postulate that exercise is not essential for the development of symptoms, but rather that it is one of several augmentation factors, citing evidence that the culprit food in combination with alcohol or aspirin will result in a respiratory anaphylactic reaction.
What Treatments Are Used If I Have An Allergic Reaction
Epinephrine is the main treatment for anaphylaxis. Once your provider has confirmed a shellfish allergy, you will most likely get a prescription for self-injectable epinephrine . Your provider will teach you how to use it.
If you have a severe allergic reaction and inject yourself with epinephrine, the next step is to call 911. Make sure to tell the dispatcher what happened and that you used your epinephrine injection. Emergency medical technicians may need to give you another dose when they arrive.
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Symptoms Of A Shellfish Allergy
Because a shellfish allergy can be serious and life-threatening, its important to recognize the symptoms and seek immediate medical treatment for a reaction. If youre allergic to shellfish, symptoms often began within minutes or an hour of eating shellfish. Symptoms can be mild, moderate, or severe. For example:
Mild shellfish symptoms include:
Foods To Avoid When You Have A Shellfish Allergy
If you’re allergic to shellfish, you need to avoid all shellfish or risk a potentially severe allergic reaction, such as anaphylaxis. This may seem like a simple taskit means you must steer clear of obvious shellfish like lobster, shrimp, and clams.
But there are actually many other types of shellfish, some of which you might not immediately recognize as shellfish. For example, you might not realize that sea urchins and octopus are shellfish. As a person with a shellfish allergy, you have to avoid all of them.
Shellfish are not the same type of creatures as fish. People with a shellfish allergy may be able to eat fish with no problem, and people with fish allergy may be able to consume shellfish.
But to protect yourself, you need to know exactly what types of sea creatures qualify as “shellfish,” and where they’re typically found in meals, both in restaurants and at home. Read on for a comprehensive guide to shellfish.
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Can You Be Allergic To Shrimp And Not Other Shellfish
However, you can also be allergic to just one type of fish or shellfish. Its even possible to be allergic to just one type of shrimp. That it is common for people to be allergic to more than one shellfish. As well, he finds between 10 and 15 per cent allergic not only to other crustaceans, but to mollusks as well.
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Treatment For Shellfish And Fish Allergies
The only current treatment for food allergies is to avoid the food that causes your allergy. Even if you are careful, it is difficult to avoid all contact with a specific food. If you are at risk of a severe allergic reaction autoinjector , ASCIA recommends that you have an action plan for anaphylaxis.If you are not at high risk and have not been prescribed an adrenaline autoinjector, ASCIA recommends that you have an ASCIA action plan for allergic reactions.To help with food avoidance, people with food allergies need to become familiar and comfortable with reading food labels. ASCIA has fact sheets to help you understand how to read food labels and what to avoid if you have a shellfish or fish allergy.Inaccurate diagnosis can lead to expensive and ineffective treatments, and unnecessary food avoidance that can lead to malnutrition and food aversion, especially in children. Always speak to your doctor about your food allergy diagnosis and treatment options.
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What Happens To Your Body
Almost everyones immune system correctly ignores all foods, so they can eat a food as much or as little as they want without ever having a problem, says Dr. Timothy Vander Leek, Associate Clinical Professor for the Division of Clinical Immunology and Allergy, in the Department of Pediatrics at the University of Alberta, and President of the Canadian Society of Allergy and Clinical Immunology . For a very small number of people, their immune system stops ignoring the food and creates an allergic antibody to that food. We dont understand why this happens, but it is more likely to happen to people with a history of other allergic problems, most importantly allergies to another food or if they have eczema.
A shellfish allergy can cause symptoms such as hives, itchiness, abdominal pain, vomiting, and tingling in the mouth. It can also cause more severe and life-threatening reactions, such as a swollen throat, rapid pulse, breathing difficulties, and a loss of consciousness. As with most food allergies, symptoms can be unpredictable, and may develop within minutes or long after eating. Its also possible to experience a more severe allergic reaction after each exposure to the food. According to Vander Leek, many people avoid shellfish and believe they are allergic because of an adverse reaction they may have experienced in the past. Allergy testing in the form of a skin prick test is the best way to determine whether you have an allergy or a food intolerance.
Most Common Age Adults That Develop Onset Allergies
A lot of the time, those that suffer from adult onset allergies have experienced some sort of allergic episode earlier in life. However, there are some cases where there was no sign of allergic reaction in that persons past. Usually if you are going to experience adult onset allergies it will be in your twenties, thirties or forties. Most people older than that dont experience these problems. All types of allergies can occur later in life including dust mite allergies, pet allergies, hay fever, mold allergies, drug allergies and food allergies.
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What Does It Mean To Outgrow An Allergy
Have you ever heard the phrase outgrow an allergy? Perhaps you yourself have outgrown allergies in the past, or you have a child who has outgrown his or her allergies. Rashes, congestion, and itchy eyes are all symptoms of allergic reactions to pollens, pets, plants, etc.
No parent wants to see their child suffer from lifelong allergies. Therefore, the hope of outgrowing allergies is a hot topic in parenthood, but what does it really mean? And is it really possible to outgrow an allergy? Lets find out.
Only Certain Foods Can Cause Food Allergies
It is true that only certain foods are most likely to cause food allergies, but children can be allergic to almost any food, including many fruits and vegetables . The foods that are most likely to cause food allergies, so-called allergy foods, include eggs, milk, peanuts, nuts, soy, wheat, fish, and shellfish.
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How Can An Adult Develop Shrimp Allergy
Q. Im 32 and just had my first anaphylaxis experience to shrimp. It was scary: I was wheezing and could hardly breathe. How can a grown woman suddenly develop a food allergy?
Dr. Scott Sicherer: You are not alone in developing shrimp allergy as an adult. In our U.S. prevalence studies and studies in Canada that tracked peanut, tree nut, fish, shellfish and sesame allergies, shellfish was the most common self-reported allergy.
We know food allergies are affected by the immune system, heredity, environmental factors, and the characteristics of the foods themselves. We know that many food allergies are outgrown, so there are clearly differences between children and adults. What we are missing are the exact details underlying each factor and how the factors interrelate. We only have theories to address your question.
The characteristics of food proteins likely play a role. Proteins responsible for persistent and severe allergies are more resistant to digestion and more likely to be recognized by the immune system. It may be that the childs immature gut or immune system is more prone to attack the proteins, but shrimp may be an example of a protein that is particularly capable of triggering an immune attack even for adults.
Another possibility is that some insult against the immune system, for example a viral illness, might trigger an imbalance, leading to a new attack on an innocent food protein.
How Is An Allergic Reaction To Shellfish Treated
If your child has a shellfish allergy , the doctor will want him or her to carry an epinephrine auto-injector in case of an emergency.
An epinephrine auto-injector is a prescription medicine that comes in a small, easy-to-carry container. It’s easy to use. Your doctor will show you how. Kids who are old enough can be taught how to give themselves the injection. If they carry the epinephrine, it should be nearby, not left in a locker or in the nurse’s office.
Wherever your child is, caregivers should always know where the epinephrine is, have easy access to it, and know how to give the shot. Staff at your child’s school should know about the allergy and have an action plan in place. Your child’s medicines should be accessible at all times. Also consider having your child wear a medical alert bracelet.
Every second counts in an allergic reaction. If your child starts having serious allergic symptoms, like swelling of the mouth or throat or difficulty breathing, give the epinephrine auto-injector right away. Also give it right away if the symptoms involve two different parts of the body, like hives with vomiting. Then call 911 and take your child to the emergency room. Your child needs to be under medical supervision because even if the worst seems to have passed, a second wave of serious symptoms can happen.
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