(RxWiki News) If you have a food allergy, you may suffer from rashes, trouble breathing and other reactions. But allergies can also lead to a disease that destroys the esophagus lining.
The digestive disorder causes swelling in the esophagus, the tube that connects the throat to the stomach. It also makes swallowing painful, and food allergies can cause it.
"Troubles swallowing? See a doctor."
The digestive disorder is called eosinophilic esophagitis, or EoE. Eosinophils are white blood cells that actively promote inflammation.
Large numbers of these cells can collect in the esophagus when an individual is exposed to an allergen. These cells chew away at the lining of the esophagus.
Hedieh Saffari, lead author of the study and a chemical engineering graduate student at the University of Utah in Salt Lake City, and her colleagues found that the current method to identify the disease may lead to the wrong diagnosis or under-diagnosis.
Currently, doctors take tissue samples from the esophagus using an endoscope with a cutting device attached. Endoscopes are tools used to visually examine a bodily canal or organ.
“Eosinophils are not uniformly distributed within the esophagus, which can lead to under-diagnosis," said study co-author Leonard Pease, PhD, assistant professor of chemical engineering and adjunct professor of gastroenterology and pharmaceutics at the University of Utah.
The scientists demonstrated that even a patient with known EoE would have to undergo more than 31 random esophagus tissue samples to reliably diagnose the disease.
Currently, if a patient is suspected of having EoE, five to 12 biopsies are collected. If more than 15 eosinophils turn up in any one sample, a diagnosis of EoE is made.
For this research, Saffari examined each of 17 tissue sections from the esophagus of a known adult EoE patient. She then made a map of eosinophil distribution in the esophagus.
The researchers found that distribution of these cells in an EoE patient is not uniform and random tissue sampling may not find the disease.
“Our analysis shows that with current diagnostic conventions, we may be misdiagnosing patients as much as one out of every five times,” said Dr. Pease. “Given this data, clearly endoscopy is not sufficient for a disease this patchy.”
While biopsies remain the current standard for EoE diagnosis, Dr. Pease and Saffari are looking into new technologies that may detect eosinophils in the esophagus at an earlier stage.
They have filed a patent for a new approach that would use “radiolabeled antibodies” to map out eosinophils.
Radiolabeled antibodies have radioactive atoms attached to them, which will allow doctors to view the eosinophils using techniques that can look at the tissues’ molecules.
The researchers expect to conduct clinical trials on this technique soon.
"We're optimistic that such a diagnostic tool could be available in the next five years," Dr. Pease said.
According to a study released in 2008 by the Centers for Disease Control and Prevention, food allergies are on the rise. There has been about an 18 percent increase in food allergy patients between 1997 and 2007.
The National Institute of Allergies and Infectious Diseases reports that 3.7 percent of adults and 6 to 8 percent of children under the age of 4 have food allergies in the U.S.
The major symptom of EoE in adults is difficulty swallowing solid food (also called dysphagia). Specifically, the food gets stuck in the esophagus after it is swallowed.
Less common symptoms are heartburn and chest pain. In children, common symptoms are abdominal pain, nausea, vomiting and coughing.
This study was published in the September issue of the Journal of Allergy and Clinical Immunology. It was funded by the University of Utah, the Utah Governor's Office of Economic Development and the National Science Foundation. No conflicts of interest were reported.