Allergic Living » adult allergy The magazine for those living with food allergies, celiac disease, asthma and pollen allergies. Fri, 20 Jan 2017 18:01:07 +0000 en-US hourly 1 Adult-Onset Allergies: Who’s More Likely to React – and Severely Thu, 20 Nov 2014 14:00:52 +0000 Bryce 2.largerDr. Paul Bryce

The older a patient is when diagnosed with food allergies, the more likely that person is to have a severe reaction, according to recent findings by Northwestern University researchers.

“We don’t know whether it’s that the actual reactions that the older individuals are having are more severe or whether some of the diseases that begin to show as people age, such as blood pressure problems or cardiovascular disease, are influencing the decision to go to the emergency room,” says Dr. Paul Bryce, one of the main authors of the study.

Food allergies affect an estimated 5 percent of adults, compared to 8 percent of children, and these rates are rising. The current understanding of food allergies is largely derived from studies based on children and infants, says Bryce, leaving a knowledge gap when it comes to adults and why some allergies can develop later in life – a gap that the study, published in the Journal of Allergy and Clinical Immunology, aimed to address.

Researchers reviewed 1,111 Northwestern University medical records of adult patients with food allergies and found that at least 15 percent of these patients were diagnosed with IgE-based food allergies when they were over the age of 18. Other findings:

  • Most patients had their first adult-onset reaction in their early 30s.
  • While in children more boys than girls have food allergies, more women than men have adult allergies.
  • The most common triggers were: shellfish and tree nuts. however, all Top 8 allergens that are seen in children were observed in adults. (Even adult-onset milk allergy.)

“With children, there’s a thinking that it may be that children have failed to develop a tolerance to the foods that they’re encountering early in life,” says Bryce. “But with these adults, we think that this is something very different. That they’re losing tolerance to foods that they’ve already been able to be exposed to and to eat. That may be an important difference in understanding how food allergy develops rather than how tolerance is not occurring in children.”

So why do some people lose tolerance as they get older? Why does age increase the severity of reactions? These are questions that Bryce and his team still do not have answers to, but he does say that their study provides important insight for the treatment of allergic adults.

“The allergists who are seeing these adults should be aware of the spectrum of foods that they may be allergic to, this concept of risk for more severe reactions as people are older, and just really understanding that these are likely to be true food allergies even though they may be against some of the foods that are typically seen in children,” he says.

According to Bryce, these findings are an early indication of the characteristics of adult-onset food allergies, but there needs to be further investigation.

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Who Is More Likely to Develop Food Allergies Later in Life? Fri, 11 Jan 2013 15:17:13 +0000 Q. I know that food allergies can crop up later in life. Is that more likely to happen to people with other allergies or asthma, or is it just as likely to happen to someone with no health issues whatsoever?

Dr. Susan Waserman: Most food allergies start in childhood, but you’re right, they can develop at any time in a person’s life.

Factors that favor the development of food allergy in adults include sensitization to pollens and house dust mites, as well as occupational sensitization (which occurs when people who regularly handle and inhale food become sensitized to it due to repeated exposures).

As well, adults with birch pollen allergy may develop “oral allergy syndrome,” which leads those affected to experience itchy mouth when they eat certain raw fruits and vegetables. This is the result of cross-reactivity between the food and the pollen.

A couple of interesting points on this topic:
• Those sensitized to house dust mites may end up with shrimp allergy because both contain the protein tropomyosin.
• Occupational sensitization is also associated with crab and pork allergies.



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How Can an Adult Develop Shrimp Allergy? Tue, 20 Mar 2012 19:54:04 +0000 115753624Photo: Thinkstock


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 child’s 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.

A route of exposure other than through the mouth may be a contributing problem for adult-onset allergy. Most food allergies that begin beyond childhood are mild reactions to raw fruits and vegetables. This type of allergy is called oral allergy syndrome and is related to proteins in pollens. For example, apple shares similar proteins with birch pollen. Thus, becoming allergic to similar proteins in the air starts the trouble.

A theory has also been proposed that environmental exposure to peanut, without actually eating peanut, may increase the risk of peanut allergy. Interestingly, shellfish proteins are similar to ones found in dust mite and cockroach, although most people with those allergies tolerate shellfish.

Digestion changes might also play a role. There are cases where adults became allergic to a food they previously tolerated after taking antacids. This theory states that the lack of stomach acid reduces digestion and allows the protein to pass to the immune system intact. This probably does not account for many cases of allergy because antacids are widely used by those who never develop problems, but it raises a possibility that some change in digestion may be a factor.

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.

The problem in figuring out why a new allergy suddenly develops is that there are numerous possibilities and nothing has so far stood out as a clear reason. The long list of possibilities, well beyond the examples I have given, presents an active area for research.

It’s important to discuss your allergy with a board-certified allergist, and to consider any circumstances that might have differed at the time of the reaction, such as exercise, alcohol or medication use, which sometimes play a role in precipitating reactions. It is important to ensure you have the correct diagnosis, learn how to successfully avoid the trigger food(s), and know what to do in the event of a future allergic reaction.


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Managing Shellfish and Fish Allergies Mon, 04 Oct 2010 15:46:50 +0000 Steamed LobstersThere is no cure for allergies to fish or shellfish, so people who develop allergies to seafood must avoid even small traces of the foods that cause them to react.

It’s crucial that people with a severe allergy to seafood carry epinephrine with them at all times, as well as other medications, such as antihistamines and inhalers, that may be recommended by their allergists.









Hidden Sources: Unlike allergens such as wheat, dairy, soy and nuts, seafood is fairly easy to avoid in processed foods. However, it does have its hiding spots, and they include: some brands of Worcestershire sauce, salad dressings, sauces, sushi, scampi, gumbo, jambalaya, bouillabaisse, spring rolls, chowder and some types of pizza. Asian foods commonly have fish and shellfish in their ingredients, so make sure to be extra careful when reading the labels on ethnic foods.

Some of the most common hidden sources of seafood are in places you might not think of: plant fertilizers, fish food, lip balm or lip gloss, and in pet foods. If you’re not sure of the ingredients, contact the manufacturer; if a product does contain the food you’re allergic to, be cautious when handling any of the items, and make sure they don’t come in contact with your food or cooking utensils.

Ironically, most imitation seafood actually contains seafood – for example, imitation crab often contains crab – so don’t assume the product is safe, and carefully read all ingredients.

Because many types of shellfish are rich in iodine, some shellfish-allergic people believe that they must avoid iodine – a common ingredient in everything from table salt to x-ray dyes. This is incorrect: the allergen in shellfish is in the flesh of the food, and not in the iodine, so iodine should be safe to consume. (Some people cannot tolerate iodine, but this is a separate issue.)

Carrageenan is made from a marine algae, not fish or shellfish, and so is considered safe for people with fish and shellfish allergies.

Supplements: One of the main hidden sources of seafood is omega-3 supplements, which are often made from ingredients such as cod liver oil and other fish oils. Many of these products are safe for seafood-allergic people to consume, because the oils are so highly refined that they have no allergic proteins left in them.

Another supplement called glucosamine, which is often used to treat arthritis, is made from the shells of crustaceans; recent studies have shown that because the shells contain no shellfish proteins, the supplement is safe for people with shellfish allergies. However, there have been reports of reactions to glucosamine in shellfish-allergic people, so you may want to stick with the vegetarian forms of glucosamine, which contain no seafood at all.

Just make sure to check with your allergist, and with the manufacturer of the product, before trying any supplements.

Eating Out: Seafood can be especially difficult to avoid in a restaurant setting. For those with fish or shellfish allergies, seafood restaurants should be avoided altogether. Chinese, Japanese, Vietnamese, Korean and Thai restaurants can be especially heavy on fish and shellfish, so it’s important to look at the menu and talk to someone at the restaurant before you eat there.

Some people with severe allergies to fish or shellfish may even react to the smell of cooking seafood, so just hanging out in a seafood restaurant, even without eating, can lead to problems.

Once you find a restaurant that isn’t seafood-heavy, call ahead and ask the manager or chef about menu items and how they handle pans and utensils in the kitchen to avoid cross-contamination. If you don’t get solid answers, or they say they can’t accommodate you, move on to a different restaurant.

When you arrive at the restaurant, tell your server about your allergy and discuss menu items that will be safe. If you don’t feel he or she is able to answer your questions properly, ask to speak to the chef or the manager. If you’re still unsure, head for the door, or stick with a beverage.

Cross-Contamination: It’s important to make sure the food you’re allergic to doesn’t come in contact with the food you are eating. That means thoroughly cleaning utensils and kitchen equipment after use. For example, if someone makes a tuna sandwich on the cutting board and you’re allergic to fish, be sure to clean the board thoroughly with soap and water before using it to make your own, safe sandwich.

Cross-contamination is a particular problem in restaurants, where pans and utensils are often shared. Make sure your server and the kitchen staff understand that even trace amounts of seafood may be a problem for you.

Also make sure to avoid foods that are deep fried in the same oil as the seafood you are allergic to. For example, if you have a shrimp allergy, don’t order those deep-fried zucchini sticks if they’re cooked in the same deep fryer as that popcorn shrimp.

Go Kosher: If you have a shellfish allergy, kosher foods are generally safe, because shellfish is not part of the kosher diet. Find grocers, markets, delis and restaurants near you that sell kosher foods and you’ll have plenty of safe items to choose from.

Call the manufacturer: If you’re unsure about whether a particular product contains seafood, contact the manufacturer by email or phone.

Most companies are accustomed to getting product inquiries from the public and are happy to help. If they can’t answer your questions, try a different product instead.

Uncertain Foods: Managing successfully means not succumbing to temptation. And this is one of the harder parts of living with a seafood allergy because it has to be done 24/7, 365 days a year. If your hostess is “pretty sure” the imitation crab doesn’t contain any real crab, just politely decline. Remember, we don’t plan accidents. The consequences of finding out the hostess was wrong are just not worth it!

At School: Although much more common in adults, children can have seafood allergy as well. For a parent of a child with seafood allergies, it’s important to communicate clearly and calmly with your child’s teacher and the principal, and to create an anaphylaxis emergency plan (also called a food allergy action plan) to protect your child.

Also ensure that the teacher (and other staff, e.g. a coach) is receiving at least annual training on using an epinephrine auto-injector and that he or she knows where your child’s “pen” is kept.



Have A Plan: Make sure to have a plan in the event of an emergency. Have your medication on hand, and make sure that your loved ones know how to administer it if necessary. And don’t forget to wear a Medic-Alert bracelet or necklace; that way, if you are unable to speak, the medical attendants can find out about your allergy. Make it a rule – no epinephrine auto-injector means no food; and if your child is allergic, make sure this rule is one he or she takes seriously.

Educate: Tell your close friends, loved ones and colleagues about your allergy, and don’t be shy about asking for what you need in order to be safe. Sometimes people don’t fully understand allergies – especially if they don’t know others with the same condition – and they may have a lot of questions, but before long they’ll get the picture.

See: Caution: Relatives Ahead

Live A Little: Don’t let your seafood allergies take over your life. With vigilance and a little extra planning, the vast majority of allergic people can live very full, normal, healthy lives. Be prepared and take the necessary precautions, then get out there and enjoy.

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What’s The Problem?




It’s a Grown-Up Thing

What’s different about seafood allergies is that they are largely an adult phenomenon. According to the FARE—Mount Sinai survey, 2.8 per cent of adults in the United States reported a seafood allergy, as compared with just 0.6 percent of children. In Canada, 1.69 per cent of adults have shellfish allergy, compared to just 0.5 per cent of children.



Why Me?

So why is it that a food you’ve always been able to tolerate suddenly starts wreaking havoc? There is no firm answer, but scientists theorize that it could have something to do with the fact that the main allergen in shellfish, the muscle protein tropomyosin, is very similar to the tropomyosin found in dust mites and cockroaches, which are some of the most allergenic pests.

So exposure to those insect proteins might actually increase a person’s odds of developing a seafood allergy. (This would also explain why studies in which orthodox Jews, who have never eaten shellfish, end up with positive results for shellfish allergy in medical tests.)

Another hypothesis is that many adults eat seafood on occasion rather than regularly, and that may affect their tolerance. In other words, the immune system may in effect forget that the food is not a problem, and may instead treat it like a harmful invader.

Pass the Caviar

It’s important to note that the key allergens in fish and shellfish are unrelated, so people who can’t eat salmon might be just fine with crab, and someone who can’t tolerate even the tiniest amounts of shrimp may be able to eat whole helpings of fresh cod.

To further complicate matters, some people only react to very specific foods: so they may be able to eat crab but not oysters, or they may be allergic to the roe (eggs) of the fish, but not to its meat. Others who cannot tolerate fresh tuna or salmon may be just fine with the same fish canned, which has led some researchers to believe that the method of food preparation could have something to do with seafood’s allergenicity.


Seafood Allergy Myths

There is some confusion about the safety of both fish oils and iodine for people with shellfish allergy.

Fish oils are popular as nutritional supplements, because they are very rich in essential omega-3 fatty acids – but are they safe for people with allergies? According to Health Canada, most of the oils are so highly refined that they no longer contain the allergenic protein, and they should be safe to consume.

However, if you have a seafood allergy, it’s important to discuss any fish products with your allergist before trying them out; it may also be a good idea to contact the company and ask them about the processes they use.

Because many types of shellfish are rich in iodine, some shellfish-allergic people are told that they must avoid iodine – a common ingredient in everything from table salt to x-ray dyes. This is incorrect: the allergen in shellfish is in the flesh of the food, and not in the iodine, so iodine should be safe to consume. (Some people cannot tolerate iodine, but this is a separate issue.)

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