Eosinophilic esophagitis (EoE) is a well studied, well defined eosinophilic disease localized to the esophagus. With a few exceptions, it is usually diagnosed pathologically by a peak value of 15 eosinophils/hpf in esophagus biopsy samples. Currently, endoscopy with biopsy evaluation is the only diagnostic for EoE considered accurate, but patient symptoms must be considered to make a diagnosis.
EoE patients are mostly male, with three times more males than females affected. Most patients are atopic, with a history of other allergic conditions. EoE usually presents in childhood or in third or fourth decade of life, but can onset at any time.
Adult EoE patients present with more uniform symptoms. They have dysphagia (difficulty swallowing), food impaction and upper abdominal pain. About 15% of dysphagia cases are caused by EoE. Food impaction requiring endoscopic intervention occurs in 33-54% of EoE adults. Children with EoE have less specific symptoms and are more likely to have vomiting and generalized abdominal and chest pain.
As mentioned above, other atopic conditions are commonly found in EoE patients. 50-60% of EoE patients have had at least one atopic condition. 40-75% have allergic rhinitis, 14-70% have asthma and 4-60% have eczema.
15-43% of EoE patients have immediate IgE mediated food hypersensitivity reactions. Food induced anaphylaxis is more likely in EoE patients than in other populations. Furthermore, a history of IgE mediated food allergy is correlated with EoE in both adults and children.
Most EoE patients are sensitized to food allergens or aeroallergens as determined by skin prick testing or serum IgE values. Local IgE production and FceRI positive cells (cells that can be activated by IgE) are elevated in biopsies from EoE patients. Six separate articles have documented seasonality in symptom severity and presentation in EoE.
High amounts of eosinophils in the esophagus (esophageal eosinophilia) can be caused by a number of conditions in addition to EoE. This includes the broader classification of EGID, GERD, Celiac disease, Crohn’s disease, hypereosinophilic syndrome, achalasia, drug hypersensitivity, vasculitis, pemphigoid vegetans, connective tissue disease, graft versus host disease, and infection. It is necessary to effectively rule out these other conditions before diagnosing EoE, and this can be difficult. Particularly, it can hard to distinguish between EoE and GERD.
Some studies have reported that significant eosinophil driven inflammation occurs in the proximal esophagus of adults with EoE but not with GERD. Surface layering of eosinophils is more typical of EoE than GERD. Some reports indicate that extracellular eosinophilic granules, including eosinophil peroxidase, major basic protein and eosinophil derived neurotoxin, are more indicative of EoE than FERD.
The cut off of 15 eosinophils/hpf is also problematic for diagnosing EoE. Surface layering and microabscesses are only found when 15/hpf are present. Additionally, basal zone hyperplasia is 44% more likely with 15/hpf and over 100% more likely with 20/hpf. Some studies have found that a large proportion of adults meeting this threshold actually have GERD. Further confusing the issue, there is a growing subpopulation of GERD excluded patients diagnosed with EoE that demonstrate a response to PPIs. This situation is increasingly being referred to as PPI responsive esophageal eosinophilia rather than EoE.
Liacouras, Chris A., et al. Eosinophilic esophagitis : Updated consensus recommendations for children and adults. J Allergy Clin Immunol 2011, pp. 3-20.
Furata, Glenn T., et al. Eosinophilic esophagitis in children and adults: a systematic review and consensus recommendations for diagnosis and treatment. Gastroenterology 2007; 133:1342-1363.