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The Nutty Nature of Nuts

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For years, patients diagnosed with a tree nut or peanut allergy have been told to avoid all nuts. But what if I told you that being allergic to one nut doesn’t necessarily mean you’re allergic to another? What if I also told you that avoiding nuts altogether could result in a higher risk of BECOMING allergic to nuts?

Nuts, right?

To make things even more confusing, it’s possible to be allergic to some tree nuts and not others (e.g., a patient could be allergic to all tree nuts except hazelnut and almond). Walnuts and pecans are almost 100% cross-reactive, so if you’re allergic to one, you’re almost certainly allergic to the other. The same is true of cashews and pistachios. But that’s pretty much where the similarities end. 

Often, if a patient has an allergic reaction to a peanut or a tree nut, their allergist will advise the patient to avoid all nuts. Why? The rationale is three-fold: 1) some tree nuts are cross-reactive with others; 2) nuts are often packaged and handled in a shared facility, making cross-contact more likely; and 3) it is often easier for a doctor to advise patients to avoid all nuts (including peanuts, which are technically a legume). 

Doctors have also generally recommended strict avoidance of all nuts after a peanut or tree nut allergy diagnosis because of the challenges in distinguishing between nuts. Otherwise, the patient would be expected to know the difference between all of the different types of nuts: almonds, brazil nuts, cashews, hazelnuts, macadamia nuts, pecans, pine nuts, pistachios, and walnuts—both shelled and unshelled. Studies have also shown that allergy patients are only slightly worse at identifying tree nuts than their allergists. 

Patients would also have to trust that kitchen and waitstaff at restaurants could distinguish between the nuts (spoiler alert: many can’t). Additionally, it’s hard to find bags of tree nuts that don’t list warnings of possible cross-contact with other tree nuts or peanuts due to manufacturing practices. In order to determine which nuts a patient is allergic to and which ones are safe, one or more oral food challenges may be necessary. 

Because of this, recommending that a patient avoid all nuts has historically been deemed the more practical—and safer—approach to food allergy management. 

Then came the LEAP (Learning Early About Peanut) study.

The LEAP study suggested that kids who were at risk for developing a peanut allergy were significantly less likely to become allergic if they ate peanuts early and often. The study also showed that if a patient was unnecessarily avoiding peanuts they were more likely to become allergic to peanuts over time. This suggested that unnecessarily eliminating certain allergenic foods could increase a child’s risk of becoming allergic.

This study led to a seismic shift in the food allergy community’s understanding of food allergies and allergy management practices. Suddenly, blanket avoidance of all tree nuts and peanuts came with the potential risk of increasing an at-risk child’s chances of developing a food allergy. For this reason, it is important that allergists talk with their patients and/or the patient’s families after a peanut or tree nut diagnosis about the different approaches to managing food allergies and decide together what is in their best interest. 

The first option is the oldest approach: strict avoidance of all peanuts and tree nuts. Many patients and families feel safe with this approach. Total avoidance may lessen the fear of a reaction due to cross-contact. Accordingly, for many patients and/or families, avoidance is the right choice. Another option is to have the patient continue to avoid the foods they are allergic to (in this example certain tree nuts) and teach families how to safely eat the foods they are not allergic to. This process may involve a food challenge. Deciding to eat certain nuts when allergic to others does involve learning how to read labels to check for potential cross-contact, learning what the different nuts look like shelled and unshelled, and understanding that eating those nuts is something that should be done at home and not in restaurants. 

We still have a lot to learn about food allergies, but hopefully in time we’ll get better at managing, diagnosing, and treating them. In the meantime, for newly diagnosed food allergy patients, candid conversations are a good start. 

 

Brian Schroer, MD is on staff at Cleveland Clinic Children’s Hospital where he sees patients of all ages with allergic and food-related diseases. 

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FPIES: Not As Delicious As It Sounds

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From time to time, we like to write about the rarer forms of food allergy. We’ve covered  Eosinophilic EsophagitisOral Allergy Syndrome, and allergies to red meat and water! Today’s blog topic will cover another lesser-known, but very serious food allergy: Food Protein-Induced Enterocolitis Syndrome (FPIES for short). 

What is it?

FPIES is a non-IgE immune system reaction to food that affects the gastrointestinal (GI) tract. IgE stands for the antibody immunoglobulin E, and most allergic reactions (think top eight most common food allergies) involve this antibody. FPIES is cell-mediated, which results in a delayed allergic reaction.

Notably, unlike typical food allergies, FPIES does not show up on standard allergy tests.

Who does it affect?

FPIES reactions often show up in the first weeks or months of a child’s life. Sometimes the child may be a little bit older if they’ve been exclusively breastfed. First reactions often occur when introducing solid foods, such as infant formulas or cereals, which are typically made with dairy or soy.

What are the common trigger foods?

For infants that experience FPIES from solid foods, rice and oats are the most common triggers. Other reported triggers include, but are not limited to: milk, soy, barley, sweet potato, squash, green beans, peas, and poultry. 

Any food protein can be a trigger and some infants may be sensitive to other foods as well. As with any food allergy, some children may only react to 1-2 foods, while others may react to several. 

What are the symptoms?

FPIES can cause severe symptoms following ingestion of a trigger food. Classic FPIES symptoms include diarrhea, severe vomiting, and dehydration. These can lead to changes in body temperature, blood pressure, and lethargy. Upon ingestion of a trigger food, there is a characteristic delay of 2-3 hours before the onset of symptoms. 

Symptoms can range from mild (such as an increase in reflux and several days of runny stools) to life-threatening (shock). In several cases, after repeated vomiting, children often begin to vomit bile. Diarrhea typically follows and can last up to several days. It’s important to note that each child is unique and may experience their own range and severity of symptoms. 

Importantly, many infants who are eventually diagnosed with FPIES are initially suspected to have a severe infection or sepsis based on their symptoms. 

How is it diagnosed?

FPIES cannot be detected with traditional allergy testing methods, such as skin prick or blood tests that measures IgE antibodies. It is accordingly tough to diagnose.

Researchers are currently looking to atopy patch testing (APT) for its effectiveness in diagnosing FPIES. APT involves placing the trigger food in a metal cap, which is left on the skin for around 48 hours. The skin is then observed for symptoms in the days following removal.

Additionally, the outcome of APT may determine if the child is a potential candidate for an oral food challenge: the gold standard for food allergy diagnosis. A medical doctor, often an allergist and/or gastroenterologist, should be involved in the diagnosis of FPIES.

Is there a silver lining?

The good news is that FPIES usually resolves with time! Many children outgrow FPIES by age 3, allowing kids to introduce the offending foods back into their diet over time. With proper medical attention and a personalized dietary plan, children with FPIES can grow and thrive! 

- Meg and the Allergy Amulet Team

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What To Expect When You’re Expecting…An Oral Food Challenge

My daughter, moments after finishing her first oral food challenge.

My daughter, moments after finishing her first oral food challenge.

This topic is pretty fresh in my mind as my daughter underwent an oral food challenge to macadamia nuts last week. In case you’re not familiar with an oral food challenge (OFC), or haven’t experienced one yet, let us fill you in.

Today, oral food challenges are considered the gold standard for food allergy diagnosis in children and adults alike. Skin prick and blood tests aid in diagnosis, but they are prone to error—false positives are not uncommon. You can read more about food allergy diagnosis methods in our blog Food Allergies Today: An Expert Q & A.

There are typically three reasons why you might do an oral food challenge:

1. You or your child tested positively for a food allergy but have never actually eaten the food.

2. You or your child tested positively for a food allergy and have eaten the food before with no symptoms.

3. To see if you or your child has outgrown a known food allergy.

An oral food challenge is usually held at your allergist’s office over a few-hour period. The allergist administers tiny amounts of the potential allergen in gradually increasing doses over a set period of time (usually 3-6 hours). In my experience, the whole challenge start to finish lasts around 4 hours. Once the full serving is administered, the doctor will typically observe the patient for a couple hours to monitor for signs or symptoms of an allergic reaction. If symptoms occur at any point during an OFC, the challenge stops and symptoms are treated immediately.

Importantly, not everyone is a good candidate for an OFC. According to allergist Dr. Jordan Scott, “when asthma is flaring or when patients are ill, we don’t challenge.”

Let’s talk about what to expect. First, block off the day, because even if the OFC is expected to last only a few hours, the experience can be emotionally draining and stressful. Being prepared and understanding the purpose and procedure is incredibly important! Below you’ll find a list of things to prepare ahead of time so you can tackle the challenge head on. 

Ask your allergist what he/she needs you to bring. He may ask you to provide the food for the challenge, or his office may provide the food (we’ve done both). If you’re providing the food, make sure you’ve done your homework to ensure it’s not processed in a shared facility or processed on a shared line with something else you’re allergic to. For example, when we challenged sesame a couple years ago, we ensured the hummus we brought wasn’t processed in a shared facility with nuts: my daughter’s other allergen. We didn’t want cross-contact playing a factor.

Ask your allergist what you should stop doing. Ask your allergist what medicines you need to stop taking before the challenge. Our allergist requires that we stop giving our daughter her daily antihistamines for seasonal allergies a few days before the challenge, as that could mask reaction symptoms during the OFC. Additionally, she cannot take any asthma medicine that day. However, if asthma symptoms start flaring, there’s a chance they’ll want to play it safe and reschedule your challenge anyway—clear communication with your allergist is key!

Bring lots of activities for entertainment. If the trial is for a child, I’ve found that new activities, games, and library books always help to hold their attention longer. Having a favorite stuffed “friend” or something that the child associates with comfort is helpful too. If you’re an adult, a good book and your favorite digital gadgets will probably suffice!

Pack safe snacks. If the challenge goes well, you may be at the allergist’s office for several hours. However, the tiny doses of food your allergist administers aren’t likely to fill you up ☺. We like to bring some of our daughter’s favorite tried and true snacks that we know are safe (another way to avoid bringing cross-contact into the equation!). Since the challenge is at an allergist’s office, and there will likely be patients in the near vicinity with food allergies, it’s an added bonus if you can bring foods that are free from the most common allergens: peanuts, tree nuts, fish, shellfish, wheat, egg, milk, and soy. I also bring disinfectant wipes in case the food spills so that I can clean it up properly for the next allergic patient. Good food allergy etiquette is important!

Bring your emergency medications. While this may seem unnecessary (hello, you’re at the allergist’s office ☺), it’s important. There’s always a small chance of a delayed reaction, and if that happens on the way home, you’ll want to have your epinephrine and antihistamines at the ready.

Stay calm. If you’re a parent accompanying a child to an OFC, it helps to remain calm if your child experiences an allergic reaction. “If a reaction occurs, it is important for parents to remain calm because children can pick up on the anxiety and feed on that,” allergist Dr. John Lee advises. If your child experiences a reaction, Dr. Lee also suggests that parents avoid calling it a “failed challenge” in front of their child, noting that “this can make a child feel as if they’ve somehow failed, or done something wrong.”

Leave the siblings at home. If the food challenge is for your child, it’s smart to leave any siblings at home so you can stay focused—especially in the event of an allergic reaction. Best-case scenario, your child doesn’t have a reaction and it ends up being quality time with your babe. If you’re an adult, you’ll still want to bring someone with you for support and to make sure you get home safely.

Set a course of action/next steps. Once the challenge is complete, talk to your allergist about next steps. If the challenge went well, make sure you know how to proceed with exposure to the food moving forward. If it didn’t, they may recommend future testing/follow up, and possibly strict avoidance of the food.

I hope you find these tips helpful! After experiencing my daughter’s first oral food challenge, I felt far better equipped to take on the second. In case you’re wondering, she passed her OFC to macadamia nuts! This is one nutritious food we can add back into her diet. Hooray!

If you’re interested in discussing oral food challenges further, let me know. We’ve been through several, so I know the ropes pretty well!

- Meg and the Allergy Amulet Team 

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