Testing & Diagnosis for Eosinophilic Esophagitis (EE) in Children

You may have heard that eosinophilic esophagitis can be difficult to diagnose, and unfortunately, that’s true. But our experts at Boston Children’s Hospital's Eosinophilic Gastrointestinal Disease (EGID) Program have lots of experience in diagnosing and caring for children with EE–in fact, we’re the largest EGID clinic in New England.

What makes it so hard to diagnose EE?

EE–and all EGIDs–can be difficult to diagnose because:

  • they’re relatively rare, and many doctors aren’t familiar with them
  • there aren’t specific symptoms that unambiguously point to EGID
  • doctors sometimes disagree over what should be considered a high level of eosinophils
  • there’s no typical way that the GI tract of a person with EE will look in an endoscopy

How do you diagnose EE?

At our EGID clinic, a thorough diagnosis of eosinophilic esophagitis is a four-step process:

Step 1. Determine whether acid reflux could be causing your child’s symptoms

The first thing we do is have your child take an acid-blocking medicine for at least four to six weeks. If his symptoms improve, it’s likely that they’re caused by gastroesophageal reflux (GERD) and not EE.

Step 2. Determine that your child’s symptoms are caused by eosinophilia in the esophagus

If his symptoms don’t improve on the acid-blocking medicine, we perform an upper endoscopy–a procedure in which the gastroenterologist slides a long, thin, flexible tube with a tiny camera on it down your child’s esophagus, and into his stomach. This lets us look for inflammation and for a high number of eosinophils.

Sometimes the eosinophils can only be seen under a microscope, so we’ll take tissue biopsies from your child’s esophagus, duodenum (part of the small intestine) and stomach. These biopsies are tiny and don’t hurt. If we see more than 15 eosinophils while your child is taking this acid-blocking medicine, we can diagnose eosinophilic esophagitis.

Step 3. Eliminate the possibility that the EE is caused by something other than an allergy

We use blood, serum and stool tests to check for evidence of an infection and rule out other conditions and possible causes of your child’s symptoms.

Step 4. Test for possible food allergies

The next step is to figure out what foods your child may be allergic to – in many cases, staying away from these foods is all the treatment he needs. Your child’s allergist will perform three types of food allergy tests: skin, blood and food patch tests.

Why do we need three kinds of food allergy tests?

Skin and blood tests pick up on different allergies, and food patch tests allow us to check for delayed allergic reactions.

Skin prick tests are used to look for food and environmental allergies. Your child’s allergist will use a small needle to prick his skin with a bit of oil from certain food extracts. The oils will stay on your child’s skin for 15 minutes, and if he’s allergic, a little hive will appear. The allergist might also use this method to test for allergies to pollen, dust, mites, mold, cat and dog dander.

The tests themselves aren’t painful, but a positive reaction could cause itching that might be uncomfortable.

Unfortunately, these tests aren’t 100% accurate, so a positive test may not mean that your child is allergic to that allergen, and your child may test negative for an allergen that he actually is allergic to. Our expert allergists have many years of experience in interpreting this data.

Some medications may interfere with the test results, and your child should not take these before his appointment with the allergist.

Blood tests (also known as RAST, or radioallergosorbent tests) are used to measure antibodies that your child’s body produces if he’s allergic to certain food and/or environmental allergens.

Blood tests don’t predict how severely your child would react to an allergen, but they do give a sense of how likely your child would be to have a reaction. These tests are also not 100% accurate, and will be interpreted by your child’s allergist. Skin prick and blood tests can be done on the same day.

Food patch tests are used to detect possible delayed-reaction food allergies. We usually test about 20 foods this way, and only ones that your child hasn’t tested positive for with skin or blood tests.

For the food patch tests, your child will be asked to visit our Allergy Program twice:

1. During the first visit, your child’s allergist uses tape to secure food patch test panels to your child’s back. These come from an allergy kit, and each one is a backing with tape that a small amount of food has been placed onto.

2. We ask you to remove the patches after 48 hours.

3. At 72 hours, you and your child come back to Children’s, and his allergist checks for any redness, swelling or hives at the sites where the patches were placed.

It’s important to remember that no test can definitively diagnose or rule out an allergy, and sometimes the doctor won’t be able to identify an allergy, and the disease will be thought to be “non-allergic” or else caused by unidentified allergies.

After these tests are complete, your child’s allergist will meet with your family to discuss the test results, and decide together on what the next steps will be.