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Food Allergies and GI System - It Can Be Confusing!


When a child has a digestive disease that is caused by an allergic reaction, it can result in uncomfortable and confusing GI symptoms. Symptoms can be vague (stomach pain, acid reflux, decreased oral intake, vomiting, swallowing difficulty, diarrhea, and blood in the stool, etc.) and can mimic many other GI conditions.

Broadly speaking there are 2 types are allergic reactions:

  1. Immediate – where symptoms start immediately and therefore it's relatively easy to identify the cause of food allergy. Classical food allergy testing – such as blood or skin testing may be accurate in the diagnosis. Example – peanut allergy causing a skin rash, breathing difficulty or vomiting, etc. An allergist can be an expert to help with these conditions. These conditions can be life-threatening. 

  2. Delayed – where symptoms can start after many hours or days after exposure to food. These are hard to find because we cannot easily correlate food exposure. These conditions can cause internal GI inflammation that can only be diagnosed with endoscopy. Allergy testing is typically not as accurate as an immediate allergic reaction. Example – Eosinophilic Esophagitis (EE or EoE). A GI doctor can be an expert to help with these conditions.

Eosinophilic Esophagitis (EoE or EE):

When the esophagus becomes swollen and inflamed due to a food allergy, it is a condition known as eosinophilic esophagitis. This causes the child to have difficulty in swallowing, acid reflux symptoms, and stomach, chest, or throat pain.

Eosinophils are white blood cells that help the body fight off attacks from infection.  They are useful in keeping our bodies healthy, but when they are produced in high numbers, they can cause what is called an eosinophilic disorder. Eosinophil production increases normally due to a food allergy or environmental reaction. When high numbers occur in the esophagus, it can result in EoE. The infiltration of these specialized white blood cells normally causes the throat to swell and includes these symptoms:

  • Problems swallowing and food getting stuck in the throat/chest

  • Acid reflux symptoms

  • Failure to thrive/reduction in weight/height

  • Pain in the belly and chest

  • Lack of appetite, nausea, and sometimes vomiting

  • Often, the child will have skin allergies or asthma

  • Family history of food allergies or swallowing difficulty

How is EoE diagnosed?

The best and most definitive way to diagnose this condition is through an examination of the esophagus using upper endoscopy. Prior to having an upper endoscopy, the child may be prescribed medication for reflux to first see if this will control the symptoms

This test, which involves light sedation, is normally done in an outpatient setting. The tube is run down the throat, esophagus, stomach, and duodenum, taking multiple biopsies to confirm the presence of eosinophil concentration. Many times, the esophagus will look normal, but under microscopic examination, the doctor may find high numbers of eosinophils.

How is EoE treated?

Most children can be effectively treated with dietary modifications and medication. The clinical dietitian can work with you and your family to ensure that you are eliminating the suspected allergens from your child’s diet. The dietitian may recommend food trials, elimination diets, or elemental diets to get the best results for your child.

Normally, dietary modification is the first step, and medication is added if the child’s symptoms are not controlled. If additional measures are needed to help relieve your child’s symptoms, the doctor may prescribe steroids to control the swelling and reduce the number of eosinophils

The most common foods causing EoE are:

  • Dairy

  • Soy

  • Eggs

  • Beef

  • Gluten: Rye, barley, and wheat

  • Nuts

  • Shellfish

Food Protein-Induced Enterocolitis Syndrome (FPIES):

When an infant or child has an extreme allergy to protein-based foods, they may be diagnosed with FPIES. Enterocolitis is inflammation that may affect both the small and large intestines. Children who have this reaction can have persistent vomiting and diarrhea and may have slowed growth. Most often, it is caused by an allergy to cow’s milk or soy, but other foods can cause the reaction.

Children who have FPIES are often first diagnosed with stomach flu, but it can always be traced back to a food allergy. The reaction begins shortly after drinking or eating the offending food. In most cases, this allergy is discovered early in life, usually in infancy. Babies who have a dairy or soy allergy react when they are introduced to solid foods that contain the ingredients.

While each child reacts differently, most will have gastrointestinal issues – vomiting and watery diarrhea – that start two to eight hours after ingestion. This reaction can continue for many days and can be life-threatening if the child becomes dehydrated or goes into shock. If this happens, it is a medical emergency and your child needs to go to the nearest emergency department for treatment.

How is FPIES diagnosed?

Since this particular allergy is normally confined to the digestive system, traditional skin and blood allergy tests are not useful. In many cases, it is confirmed when a child has more than one allergic reaction.

How is FPIES treated?

Many children grow out of FPIES over time, so it is not a lifelong condition, but it can be dependent on the particular food. Dairy allergies are more longstanding and impact children for a greater time.

For infants who are diagnosed with FPIES related to dairy and soy, they are normally switched to a hypoallergenic formula. Older children simply avoid the food that causes the reaction. Over time, you can work with our staff on reintroducing foods to see if there is a reaction. This will be carefully monitored through in-house testing to ensure your child’s safety.


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