Welcome! I have heard that desensitization can cause EoE if people 'push through' stomach pain symptoms.
EoE is diagnosed by first having a scope with biopsy and then going on a PPI for at least a few months and then get another scopy/biopsy. If a person has 15 or more eosinophils/HPV then they get diagnosed with EoE at that time.
If a person has EoE there are two main treatments, each of which are about equally effective. People either avoid the top 8 food triggers (dairy, eggs, peanuts, tree nuts, wheat, soy, fish and shellfish) or take swallowed steroids.
It sounds like your doctor may not have followed all these steps.
This website has good info. http://apfed.org/about-ead/egids/eoe/?q=what_is_eoe