An eosinophil (e-o-sin-o-fill) is a type of white blood cell. Eosinophils are the least common of the white blood cells and make up about 1 to 4 percent of the blood's cells. Named after "Eos," the Greek goddess of dawn, eosinophils are characterized in their laboratory slides by their bright red-pink color and double nucleus. Eosinophils are most commonly associated with allergic diseases and parasite infections.
Eosinophilic (e-o-sin-o-fil-ik) esophagitis (e-so-fa-gi-tis), referred to as EoE, is an chronic allergic inflammatory disease of the esophagus, the muscular tube that carries food from the throat to the stomach. In the past, it has been referred to as EE.
During an allergic reaction, various cells congregate and cause symptoms like redness, swelling and itchiness. A white blood cell called an eosinophil is one of the types of cells behind an allergic reaction.
Eosinophils are an important part of the immune system and there are always small quantities in the blood and intestine fighting parasites and performing other duties. However, eosinophils cause problems when they appear in high quantities in areas other than the blood and intestine.
If you have seasonal allergies, eosinophils are in your nose; if you have asthma, they are in your lungs; and if you have EoE, they are in your esophagus.
Children experience nausea, regurgitation, vomiting, abdominal pain and a burning feeling similar to acid reflux (heartburn). They may have difficulty swallowing and gag frequently. Often, they feel like something is stuck in their throat. This is called dysphagia. If EoE goes untreated, the esophagus may narrow because of scarring. This is called stricture.
Infants with EoE don't want to breastfeed or take a bottle, and may frequently spit up and arch the back — a sign of pain. Older children eat reluctantly and slowly, don't grow as quickly as expected, develop seemingly irrational aversions to certain foods, and may have trouble sleeping. They may complain of heartburn and dysphagia. Sometimes EoE is diagnosed after a child or teenager comes to the hospital with food in the esophagus that he or she is unable to cough up. This is called food impaction.
EoE shares many symptoms with acid reflux, so a doctor will first prescribe an acid blocker medication or proton pump inhibitor (PPI). These medicines do not help EoE, so if symptoms persist, the doctor will know reflux isn't the cause. It's estimated that up to 10 percent of children with reflux have EoE.
We don't know what causes EoE or why it often seems to run in a family. There are several theories, but none have been investigated enough to prove or negate them.
Eosinophilic esophagitis affects children of all ethnicities and family income levels. Children with EoE often have other allergic disorders like asthma, seasonal allergies or eczema.
The only way to diagnose EoE is by a biopsy of the esophagus, performed by a gastroenterologist. The child is sedated and the physician inserts an endoscope into the mouth and through the esophagus, stomach and upper part of the small intestine, where a small sample of tissue is taken.
Sometimes, the gastroenterologist can see signs of EoE in the esophagus, such as "rings" or "white plaques". However, in many cases a child can have EoE and esophageal tissue that appears to be normal. Therefore, it is critical to obtain an esophageal biopsy sample.
Typical allergy tests, such as skin or blood tests that identify immediate allergic reactions, are not usually effective for diagnosis of eosinophilic esophagitis because the allergic reacting involved in EoE is often delayed several days after an allergen is introduced.
Skin patch test is often more insightful, but is not routinely offered by most allergists. Both tests are guidelines on how to introduce foods but like all tests nothing in 100 percent predictive.
Almost always the underlying cause of eosinophilic esophagitis is a food allergy. A gastroenterologist or allergist may implement dietary restrictions to pinpoint the food that triggers the allergic response. The most commonly involved foods include:
However, almost all foods have been implicated. Some patients may simply be allergic to a single food while others may be allergic to many foods.
Because allergy tests are often unable to determine the causative foods, complete elimination of all foods may be required. In these cases, patients must be placed on a strict elemental formula for one to three months in order to heal the esophagus.
After this, foods are slowly reintroduced in an attempt to discover the food(s) causing the allergy.
Repeat endoscopy with biopsy is often necessary. Several medications have been tried including corticosteroids. While these medicines reduce esophageal inflammation, when withdrawn, the disease recurs.
Thirty years ago, EoE was unknown. Diagnoses have risen dramatically in the past five years. We don't know whether this is because the disease is actually becoming more common, or because it's being recognized much more often. Probably the rising number of cases is due to some combination of the two factors. EoE is still a rare disorder, occurring in an estimated 1 in 1,500 children.
Based on what we know today, most children do not outgrow eosinophilic esophagitis. However, ICD-9 codes for eosinophilic diseases were not approved by the National Counsel for Health statistics (NCHS) until July of 2008, making it difficult for researchers to accurately track the progress of patients over time. With codes in place and through collaborative efforts with other pediatric and adult institutions this will continue to be an area of research.
With diet modifications — and possibly some lifestyle adaptations that center around food — your child will thrive and have the ability to live a very full life, even if his or her EoE never completely goes away. However, we don't know the long-term effects of EoE.
Some results of the disease, such as scarring of the esophagus, are troubling. As the current population of children with EoE enters adulthood, we will be able to answer more questions about its long-term health effects.
If you think that your child may have eosinophilic esophagitis, contact your primary care physician. He or she may then refer you either to a pediatric gastroenterologist or allergist for further evaluation.
Updated: October 2012
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