GERD causes symptoms of heartburn and food sticking but so can an allergic condition of the esophagus known as eosinophilic esophagitis (EE). EE is characterized by the presence of an abnormal number of allergic type cells called eosinophils in the esophagus. In many patients and the number of eosinophils may not be high enough to separate EE from GERD, however a new study found another allergy cell, the mast cell, may help differentiate allergic esophagitis from acid reflux esophagitis. This study also provides further support that some people have both acid reflux and allergy.
Eosinophils are not normally present in the esophagus but are seen in small numbers under the microscope in biopsies of esophagus due to acid reflux. A count of more than 15-20 eosinophils per high power field (HPF or 40x) is the usual range considered diagnostic of EE though some pathologists use 24 or more. In reflux, up to 7 eosinophils per HPF is considered typical.
This study found significantly higher eosinophils (on average 55/HPF) in EE along with the presence of mast cells compared with reflux. However, though 96% of the EE biopsies showed IgE on cells so did 41% of those with GERD. This is consistent with some earlier studies that have suggested some people with reflux, especially those with more than 7 eosinophils per HPF, also have an allergic component. This also may explain the failure of acid blocking medications alone to relieve the symptoms in some people with reflux. The study also highlights the importance of biopsies even when the gut appears normal. Recent studies have also confirmed the presence of mast cells in the intestine of people previously labeled as irritable bowel syndrome. Microscopic signs of allergy, food intolerance or inflammation may be present in a normal appearing digestive tract but won't be discovered if a biopsy is not done. One could argue that biopsies should be done on all who have symptoms regardless of the appearance visually.
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Reference: Activated mucosal mast cells differentiate eosinophilic (allergic) esophagitis from gastroesophageal reflux disease. Kirsch R et al. Journal of Pediatric Gastroenterology and Nutrition 2007;44:20-26.