Gastrointestinal-type allergic disorders increasing

Diagnosing these conditions often requires a pathologist, a gastroenterologist and an allergist.

Issue: July 2008

Major advances have been made in the diagnosis of gastrointestinal-type allergic disorders, according to Chris Liacouras, MD, who spoke at the recent 2008 Annual Meeting of the Pediatric Academic Societies, held in Honolulu.

“During the past 10 years, we have seen an increase in gastrointestinal-type allergic disorders — not only eosinophil disorders but also celiac disease. It often takes a well-trained pathologist, gastroenterologist and allergist working together in order to determine what foods are causing the issue,” said Liacouras, who is a professor of pediatrics at the University of Pennsylvania in Philadelphia.

Food/GI interactions

Foods such as lactose, caffeine and spicy foods interact with the gastrointestinal system in many ways. Some foods produce symptoms without significant histologic abnormalities, whereas other foods do.

According to Liacouras, the presence of eosinophils in the gastrointestinal tract does not necessarily mean that a patient has an allergy, and a patient with an allergy will not necessarily have eosinophils in the gastrointestinal tract.

“Pathologists really have to understand what we need to look for and what they need to tell us so we can decide as a clinician how to treat these patients. Basically, eosinophils are normally present in the majority of the gastrointestinal tract. This is important because when a pathologist sees an eosinophil, he or she may think that allergy exists, when in fact the baseline level of eosinophils are normal in that patient. In general, eosinophils are present in all areas of the gastrointestinal tract, except the esophagus,” he said.

He said that the results of some pathology studies have shown that the number of eosinophils vary geographically in the gastrointestinal tract. More importantly, the number of eosinophils differs depending on a patient’s location in the country. People in the South have larger numbers of eosinophils than some people in areas in the North.

“So, you must have a pathologist who you trust and who knows about these differences to really give you an idea of whether there is an eosinophilic process going on in the gastrointestinal tract,” he said.

Typically, large numbers of esophageal eosinophils are an indication of reflux or food allergy. Liacouras said that patients should be treated aggressively with acid blockade before the diagnosis of eosinophilic esophagitis can be made. “We often see patients who have symptoms of reflux, treat them with acid blockade, subsequently perform an endoscopy if their symptoms do not improve or their medication cannot be weaned. We’ll find that eosinophilic esophagitis is often present if they are not doing well with the acid blockade,” he said.

Celiac disease

Celiac disease is a food allergy and is an immune-mediated enteropathy caused by sensitivity to gluten. Patients may present with gastrointestinal symptoms, but some patients do not experience these symptoms.

“Celiac disease can be related to many different disorders, such as other autoimmune disorders, and we are diagnosing more and more patients with celiac disease than we have previously.”

“The newer thought is that it’s an autoimmune condition that occurs in genetically-susceptible individuals. There is definite evidence that genes are associated, and testing can be done to diagnose celiac disease. It is a unique autoimmune disorder because if the environmental trigger is removed, the disease improves,” Liacouras said.

Additionally, some patients can experience atypical or silent symptoms. For example, patients who have arthritis or anemia may have celiac disease. Serologic testing can be done to screen patients who are asymptomatic but who are at risk because other family members have celiac disease. This testing can be used to screen symptomatic patients, and it can also be used to monitor patients after they have been diagnosed with celiac disease.

Eosinophilia

In addition to food allergies, infectious and neoplastic processes can also cause eosinophilia in the gastrointestinal tract. However, most cases are related to food allergy.

With eosinophilic gastroenteritis, a large number of eosinophils are seen mostly in the stomach, but they can also be seen in the small bowel and the large bowel but not in the esophagus.

Eosinophilic colitis occurs mostly in infants who have milk protein allergy and bloody stools. “Eosinophilic esophagitis is isolated to the esophagus, and we have seen more and more cases of this during the past few years,” he said. – by Michelle Stephenson

For more information:

Liacouras C. Spectrum of allergic bowel disorders. #4192. Presented at: the 2008 Annual Meeting of the Pediatric Academic Societies; May 2-6, 2008; Honolulu.