Viewing entries in
Rare Allergies


FPIES: Not As Delicious As It Sounds


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



You Down with EoE? No Thanks, Not Me.


Every now and again our team at Allergy Amulet likes to post blogs about lesser-known conditions that affect the food allergy population (our people)! One such blog, I’ll Take My Allergies Medium Rare, covers some uncommon (but very real) forms of allergy. Today’s installment is no different! Have you ever heard of a condition called Eosinophilic Esophagitis (E-o-sin-o-fill-ik Uh-sof-uh-jie-tis), or EoE for short?

What is it?

If you have EoE, a large number of white blood cells (eosinophils) build up in the lining of the esophagus (the tube that connects your mouth to your stomach). This buildup is a reaction to food, airborne allergens, or acid reflux, and can inflame and injure esophageal tissue. EoE is a recognized chronic allergic/immune condition, and is not typically outgrown (but it can be managed)! EoE is a relatively new disease, as it has only been identified in the past two decades. Accordingly, there is still much to learn about this complex condition.

Who does it affect?

EoE affects approximately 1 out of every 2,000 people in the United States. In recent years, allergists and gastroenterologists are seeing an increasing number of patients with EoE—this is presumably due in large part to greater physician awareness about the condition. Most patients with EoE are considered atopic, meaning they have a family history of allergies, asthma, or symptoms of one or more allergic disorders. These can include food allergies, eczema, seasonal allergies, and asthma. For patients with environmental allergies, their EoE may be worse during pollen season. Allergic reactions to food are the main cause of EoE in many patients, and foods such as dairy, soy, wheat, and eggs are often the main culprits. Interestingly, according to Dr. Jordan Scott of Boston Children’s Hospital, the development of EoE has occurred as a side effect of oral immunotherapy for food allergies in up to 3% of cases.

What are the symptoms?

EoE symptoms vary depending on age. Infants and toddlers may refuse food or fail to gain weight. School-age children often experience difficulty swallowing, vomiting, or have recurrent abdominal pain. Teens and adults generally have trouble swallowing, especially dry or dense solid foods. In some cases food can get trapped in the esophagus, which can lead to choking.   

How is it diagnosed?

There are certain criteria for diagnosing EoE that most allergists, gastroenterologists, and pathologists agree on: symptoms consistent with EoE, an upper endoscopy procedure (lets the doctor see what’s happening in your esophagus), and an esophageal biopsy (tissue samples of the esophagus are taken and analyzed). A specialist may also recommend further evaluation (e.g., a gastroenterologist may refer a patient to an allergist for food allergy testing and vice versa).

Is there a silver lining? 

The rise in EoE cases has led to greater physician awareness and further research around the condition. Additionally, a wide variety of treatments have been identified for those managing EoE, such as:

1.    Empiric elimination diet—removing major food allergens (e.g., dairy or wheat) from your diet and gradually adding them back in one at a time under close physician watch and guidance. This diet is often most successful with the help of a dietitian, as it can be tough to manage.

2.    Elemental diet—all sources of protein are removed from the diet and replaced by an amino acid formula, oils, and simple sugars. This treatment is often reserved for children with several food allergies who have not responded to other treatments.

3.    Medical therapy—swallowing small doses of oral corticosteroids has proven effective for managing inflammation. Proton pump inhibitors are also used to control acid production. 

Each of these treatments has its advantages and disadvantages, so it’s helpful to first discuss them with your physician before trying any one approach. One challenge with treatment, according to Dr. Scott, is that patients must typically undergo multiple endoscopy procedures to ensure that esophageal inflammation is improving with meds, dietary avoidance, or both.

The good news is that you don’t have to go it alone! There are numerous support groups and organizations out there that can help, such as APFED and CURED. When it comes to understanding and managing immune conditions, having a trusted support network is key!

- Meg and the Allergy Amulet Team 



I'll Take My Allergies Medium Rare

If you’ve followed Allergy Amulet lately, you know we LOVE to talk about food allergies. Recently, we discussed the phenomenon of Oral Allergy Syndrome: a typically mild allergic reaction that can occur after eating a raw fruit or vegetable. This got us thinking: What other unusual allergy phenomena are out there?

We attempt to answer just that question in this post, because allergies aren’t always as common as peanut, pollen, and pet dander. They can also include red meat, metal, and even WATER!

While rare, these allergies are just as real. Here, we break them down for you.  

1.    Red Meat

If you’re a Radiolab fan like we are, you are definitely going to want to tune in to this podcast. The podcast follows the story of a woman who developed a meat allergy from a tick bite! One bite from a Lone Star tick can cause people to develop an allergy to red meat, including beef and pork. This type of allergy has been attributed to a sugar in meat called “alpha-gal.” Individuals bitten by the tick develop antibodies against this sugar. Symptoms include congestion, rash, nausea, swelling, and even anaphylaxis. Symptoms usually manifest within 4 to 6 hours after eating red meat. That said, be sure to check for ticks if you’re hiking in THIS region of the US! Additionally, a letter recently published by researchers in the Journal of Allergy and Clinical Immunology warns that the Zoster (shingles) and MMR (measles, mumps, and rubella) vaccines have been linked to anaphylactic reactions to meat.

2.    Exercise

This type of allergy has been reported only about 1,000 times since the 1970s. Exercise-induced allergic reactions typically occur during or after exercise, and generally follow from eating certain foods beforehand. Symptoms range from a mild rash and hives to anaphylaxis. The most commonly-reported incidents of exercise-induced anaphylaxis involve wheat, shellfish, tomatoes, peanuts, and corn.

3.    Gelatin

Gelatin—a protein derived from collagen—forms when connective animal tissue or skin is boiled. Allergic reactions to gelatin are often linked to vaccines, as many contain porcine gelatin as a stabilizer. Gelatin is also found in most gummy candies, as well as in products like marshmallows and some ice creams, dips, and yogurts. If you thought you were allergic to gummy bears, it may actually be gelatin!

4.    Leather

Have you ever experienced a foot rash after wearing leather shoes? Leather probably isn’t the culprit—you’re more likely allergic to the chrome used in the tanning process. Leather allergies are generally restricted to skin rashes. Several well-known car companies actually avoid using chromium on their leather seats because of this known allergy. So if the anti-fungal powders aren’t working, and you wear leather shoes, it may be because you have a chrome allergy!

5.    Water

Water-you talking about?! Yes, there is such a thing as a water allergy. An allergy to water, or aquagenic urticaria, is very rare. There are less than 100 cases reported in medical literature. Affected individuals typically develop hives when their skin comes in contact with water, regardless of the temperature. This condition appears more commonly in women, and most often during puberty. The hives and itchiness most often appear on the neck, upper trunk, and arms, and usually go away in 15-30 minutes. Antihistamines generally help relieve symptoms.

6.    Latex

Latex allergy is most commonly diagnosed in individuals frequently exposed to latex, such as healthcare professionals. It’s estimated that less than 1% of the US population has an allergy to latex, but for those in the healthcare sector, it’s closer to 8-17%! Interestingly, a latex allergy can also produce an allergic reaction to certain foods because of cross-reactivity (check out our blog post on Oral Allergy Syndrome to learn more about this phenomenon)! Individuals with a latex allergy need to stay alert, as latex can hide in unexpected places like mattresses, root canal sealant, utensils, and spandex. 

7.    Spice

It is estimated that 2-3% of individuals live with a spice allergy. Allergies to spices such as garlic or coriander are rare and usually mild, although severe reactions have been reported. Reactions can occur from inhalation, ingestion, or touch. A spice allergy can be difficult to manage as spices are commonly used in foods, cosmetics, and dental products. For example, dentists often apply cloves to extracted wisdom teeth cavities after the operation. A good reminder to alert your dentist of all of your allergies—especially rare ones!

8.    Nickel

Nickel allergy is a common cause of contact dermatitis—an itchy rash that pops up when your skin touches a normally harmless substance. Nickel is a silvery metal that is regularly mixed with other metals to form alloys. It is most often associated with earrings and other jewelry, but can also be found in many everyday items like cell phones, chairs, zippers, coins, and eyeglass frames. It may take repeat or prolonged exposure to items containing nickel to develop an allergy. Treatment may reduce the symptoms, but once you develop a nickel allergy, you’ll always be sensitive and will need to avoid exposure.

9.    Touch

Dermographism urticaria, or “skin writing,” is a type of allergy where you can write on your skin with the pressure from your fingernail. Firm pressure on the skin creates red wheals, which may accompany itching. Dermographism affects approximately 4% of the population. It can manifest at any age, but is most common in young adults. Symptomatic dermographism is usually idiopathic (of an unknown cause), though it may have an immunologic basis in some patients. Trauma to the body may play a role as well. This type of rash typically goes away after about 15-30 minutes, and can be controlled with antihistamines. 

10. Cold

Last but not least is an allergy to cold temperatures. Yes, you read that correctly. Cold urticaria is a skin condition that manifests when the skin is exposed to low temperatures. It is most common in young adults. Symptoms are generally limited to hives; however, the severity of cold urticaria varies widely. A whole body (systemic) reaction—the more severe form—typically occurs after swimming in cold water. This can lead to low blood pressure, shock, and even death. The cause for this allergy is poorly understood. The good news is that this type of allergy generally only lasts a few years.

So, have we sufficiently scared you? Or are you now more fascinated by the human immune system than ever before? We hope it’s the latter!

-       Meg and the Allergy Amulet Team


Allergy Amulet advisors Dr. Jordan Scott and Dr. John Lee have reviewed this piece for accuracy. 

Dr. Scott is an allergist/immunologist and operates several private allergy clinics throughout the Boston area. He is on the board of overseers at Boston Children’s Hospital, and the past president of the Massachusetts Allergy and Asthma Society. Dr. Scott is an allergy/immunology instructor at the University of Massachusetts.

Dr. Lee is the clinical director of the food allergy program at Boston Children’s Hospital and an Instructor in Medicine at Harvard Medical School. He is also the co-creator of, a website that offers online resources to help educate and promote awareness about food allergies in schools, camps, and other settings. Dr. Lee is widely recognized for his work in the food allergy space, and his commitment to patient health.