Eosinophilic Colitis

What is Eosinophilic Colitis?

Colitis is the medical term used to describe generally a condition in which an individual’s colon (the lower portion of the large intestine) becomes inflamed. Although the condition has numerous established causes such as a bacterial or parasitic infection, in many instances an exact cause has not been identified. The inflamed colon is less able to absorb water, its principal function. As a result, sufferers experience gastrointestinal problems, including diarrhea (or, somewhat unexpectedly, constipation), often accompanied by abdominal cramps, nausea, fever or weight loss.

Eosinophilic colitis, also known by the initials “EC”, is a relatively rare type of colitis that occurs most often newborns and in adults between the ages of 30 and 50, although cases have been reported in much older individuals. It has not been shown to occur more frequently in either males or females, nor is it more common in any specific ethnic or socioeconomic group. EC is the least commonly diagnosed member of a larger group of disorders known as eosinophilic gastrointestinal diseases, or EGDs, which also include eosinophilic inflammation of the esophagus and small intestine.

Eosinophilic colitis and the other EGDs are named for the presence of eosinophils, a type of white blood cell. When stained with the dye eosin and viewed through a microscope, tissue containing eosinophils exhibits eosin’s telltale bright pink or red hue. As is true of all white blood cells, eosinophils are an essential part of the human body’s system of defense against infection by bacteria, viruses and other foreign bodies and substances.

Eosinophils are the least numerous white blood cells typically making up not more than 4% of all blood cells. They remain in the blood, ready to be released into tissues in response to an infection. Once released, white blood cells surround and, in effect, digest the invading organisms. The white blood cells die in the process and, normally, the production of new white blood cells then stops. However, in the body of an EC patient, the immune system continues to produce new eosinophils even after the original cause has been eliminated. No longer having “enemy” cells to destroy, they instead attack the colon’s own cells, causing inflammation and eventual loss of healthy tissue.


Numerous articles and studies have concluded that a food allergy is the most likely cause of eosinophilic colitis, particularly in infants. Many patients do have a history of such allergies and exhibit a clear connection between the consumption of certain foods and the onset of symptoms. However, as is the case with several of the so-called inflammatory bowel diseases (IBDs), there is no consensus as to any single, universal cause of EC. Indeed, some researchers suspect that the condition is not the result of any single cause and is instead caused by a complex interaction, as yet only vaguely understood, among several internal and external factors. Many also believe that the specific combination of causes varies from patient to patient.

There is some evidence to suggest that EC patients may have a genetic abnormality that makes them more susceptible to developing the disorder, though a number of studies indicate that the condition may be the result of an underlying undiscovered and therefore untreated bacterial or parasitic infection in the patient’s digestive tract. Environmental agents are also thought by some to be an factor and, while not typically viewed as an independent cause, emotional stress may aggravate the inflammation caused by an attack.


Although symptoms of eosinophilic colitis vary, the most common are unexplained weight loss, loss of appetite, persistent watery diarrhea or constipation, bloody bowel movements, severe abdominal cramps, nausea, vomiting and fever. Blood tests may also reveal that the EC patient is experiencing low levels of certain key proteins and iron, usually due to his or her persistent loss of blood. In some instances, an examination of the colon may reveal a thickening of its walls as well as the development of fluid or an intestinal blockage.

Because EC is considered a chronic disease, it is not unusual for symptoms to occur without apparent cause or prior warning and then abruptly subside, even without treatment. Eosinophilic colitis patients often experience periods of significant and even debilitating symptoms that can last for several days or longer. These periodic “flare-ups” may be followed by brief or extended periods during which symptoms disappear or become manageable.

The unpredictable nature of EC attacks typically forces both the adult and child patient to make major changes in his or her diet, daily activities, work or school schedule and other daily routines. During a flare-up, it may be impossible for the patient to work or attend school, and even while on the job or in class fear of an attack may affect the patient’s work or academic performance. There appear to be no reliable statistics regarding the amount of work and school absenteeism or lost productivity that can be directly attributed to eosinophilic colitis or to EGDs in general, but the discussions in Internet support groups indicate that these concerns are shared by many sufferers and their families.


Outward symptoms of alone are not sufficient to support a diagnosis of eosinophilic colitis. This is because the same symptoms are associated with other IBDs, including Crohn’s Disease and ulcerative colitis. Other non-IBD conditions such as irritable bowel syndrome (IBS) may also cause such symptoms. For this reason, a preliminary diagnosis of eosinophilic colitis can only be made by performing an internal examination of the colon (called a colonoscopy) during which a small sample of colon tissue is obtained, then stained and examined under a microscope. However, the presence of excessive numbers of eosinophiles in colon tissue can be associated with other conditions, including a parasitic or bacterial infection and reactions to certain prescription antibiotics and other drugs. As a result, eosinophilic colitis is referred to by physicians as a “diagnosis of exclusion”, that is, one that can be confirmed only by conducting additional tests in order to rule out other possible causes. These additional procedures may include testing of stool samples for the presence of parasites or the administration of a barium x-ray of the intestines in order to identify the presence of fluid buildup or blockage.


Though there is as yet no cure for eosinophilic colitis, a number of steps can be taken in order to relieve its symptoms or reduce their severity. Removing from the diet foods or individual food ingredients – particularly proteins – known to trigger flare-ups can provide significant relief, especially in pediatric sufferers. Unfortunately, this can be a tedious and frustrating process of trial and error, and symptoms can of course recur until the offending substance is identified. Because allergies to multiple food ingredients are not uncommon, identification and elimination of several allergens may be required. The adult patient or the caregiver of a child with EC must also become sensitive to the presence of “hidden” ingredients in commercially prepared foods. For example, eggs or egg protein may appear on an ingredient label under one of nearly a dozen different names. To speed the identification process when a food allergy is suspected, the treating physician may first test for allergies with skin prick or patch tests in an effort to isolate the allergen.

For some eosinophilic colitis patients, temporarily following a strict “elemental” diet – which eliminates all proteins – is necessary in order to help determine whether the symptoms are in fact caused by a food allergy. So called “food trials”, in which the patient is first placed on an elemental diet and then permitted to reintroduce one type of protein at a time, can also speed up the process of identifying the specific triggering ingredient.

While a dietary change does produce relief in many eosinophilic colitis patients, by itself the elimination of certain foods may not be sufficient, and medication is required to relieve EC’s inflammation and allow the colon to heal. The most commonly prescribed drugs are steroids, which are effective in many cases. Unfortunately, long term use of steroids is not recommend, since such use is known to cause a long list of undesirable or even dangerous side effects, including high blood pressure, elevated blood sugar, cataracts, muscle weakness and osteoporosis. For this reason, steroids ordinarily will not be prescribed for use as a preventive, but only to treat flare-ups. Once the inflammation is brought under control, however, there are several currently-approved non-steroid medications that can be prescribed to keep the symptoms at bay.

Although eosinophilic colitis is relatively rare, eosinophilic gastrointestinal disease in general is fairly common. As such, there is continued research into both causes of and new treatments for these disorders.

For more detailed information check out the list of topics about eosinophilic esophagitis.

You can also ask questions and communicate with others about the disorder by becoming a member of the free Eosinophilic Esophagitis Forum.[/four_fifth]