All three of my children have food allergies.  My two daughters have minor symptoms but my son has eosinophilic esophagitis and has had to have his esophagus dilated twice.  Why the difference? 

The short and sweet answer is gender.  First off, all food allergy is quite common, affecting up to 15% of Americans at some time during their lives.  The resultant symptoms can vary from trivial to life threatening anaphylaxis (such as severe peanut allergy).  Also, the “target organ” of the food allergy can vary from the skin, to the sinuses, to the lungs, to the GI tract.  Eosinophil esophagitis (EOE) tends to be one of the more troublesome manifestations.  The allergy leads to inflammation in the esophagus causing heart burn, reflux, and sometimes strictures, with resultant sticking of food.  If mild the lodged food can be vomited out, but sometimes it has to be removed via endoscopy. 

As it turns out, EOE is four times more common in males than in females.  It also tends to be more severe in males than in females with more frequent development of strictures.  The gender difference turns out to be due to a protective effect of estrogen, specifically 17-Beta-Estradiol.  Estrogen can affect physiologic processes beyond reproductive function by its effect on the immune system.  Estrogen receptors have been found on T and B lymphocytes, other white blood cells and on natural killer cells, all of which can mediate allergic inflammation.  By downregulating the inflammatory response, estrogen protects the esophagus from the severe inflammation that can occur in males. 

Researchers at the University of Michigan and the University of Cincinnati have recently found estrogen receptors in esophageal tissue of both sexes.  Based on these findings they plan to investigate the plausibility of using a dilute estrogen solution to swallow as part of a healing therapy.  They hope

that very dilute concentrations would work in males, but not adversely affect their hormonal balance.