Eosinophilic esophagitisK20

Attwood SE et al., 1993

Chronic inflammatory, immune-mediated, esophageal, eosinophilic mucositis with esophageal dysfunction and eosinophilic mucosal infiltration (>15% eosinophilic granulocytes/ visual field)

EoE occurs worldwide. The prevalence of 50/100,000 inhabitants refers to industrialized European countries and the USA. There are also cases from Asia and the Middle East. India and sub-Saharan Africa are an exception, as no cases have been documented from these areas Reed CC et al. (2019).

m:f=3:1

Animal models, genetic studies, comorbid allergic diseases and the effectiveness of elimination diets indicate that EoE is an atopic disease (Reed CC et al. 2019).
Food allergies can be detected in around 50% of cases(wheat allergy, cow's milk allergy). Most patients are sensitive to one or more foods and have a hypersensitivity to aeroallergens or a respiratory allergy. The role of antigen sensitization is supported by clinical and histological improvements in elimination diets without triggering allergens. Increasing data show that EoE is not IgE-mediated and IgG4 may play a role in the development of EoE (Reed CC et al. 2019).

In children, food allergies are mainly detected, while in adults, aerogenic allergens are more likely to be suspected.

Food allergens and aerogenic allergens trigger an inflammatory reaction with activation of the Th2 signaling pathway. The Th-2 cytokines (IL-13, IL-9, IL-5 ) stimulate the production of eotaxin-3 and periostin from hyperplastic epithelial cells with adhesion and recruitment of eosinophils and mast cells.

Role of the epithelial barrier: SPINK7 has been shown to be part of the differentiation program of the human esophageal epithelium. The absence of SPINK7 in the epithelial cells of the oesophagus appears to lead to a dysfunction of the epithelial barrier in humans (Lyles J et al. 2019). In eosinophilic esophagitis, SPINK7 (as well as SPINK5) is only expressed to a small extent. Its depletion is of pathogenetic relevance for eosinophilic oesophagitis (Azouz NP et al. 2018). Apparently, the loss of cellular differentiation and the altered gene expression lead to an allergic immune reaction.

EoE is more common in cold and dry climates and in rural areas and most commonly affects people younger than 50 years,48 men and Caucasians (Reed CC et al. 2019).

Variable intensity dysphagia, bolus obstruction, possibly heartburn or other symptoms of gastroesophageal reflux (GERD).

In children: abdominal pain is common.

In some cases, bolus obstruction may be the first clinical sign of the disease.

Often eosinophilic esophagitis is accompanied by diseases of the atopic type such as:

• Eosinophilic gastroenteritis
• Eosinophilic colitis
• bronchial asthma (24% of cases)
• atopic dermatitis
• rhinoconjunctivitis allergica
• Food allergies.

Exact comparative figures emerged in a larger study by Mohammad AA et al (2017), who compared the prevalences of patients with eosinophilic esophagitis in terms of comorbidities of asthma, allergic rhintis, and atopic dermatitis, with atopic patients without eosinophilic esophagitis. In the United States, the prevalence of:

• asthma to 22.3
• allergic rhinitis at 19.1%
• atopic dermatitis 8.3%.

estimated. In contrast, their prevalences in patients with eosinophilic esophagitis +:

• asthma at (22.3) 39.0 %
• allergic rhinitis at (19,1) 61,9 %
• in atopic dermatitis in (8,3) 46,1 %.

These constellations suggest a strong association between atopic diseases and eosinophilic esophagitis. Moreover, patients with concomitant eosinophilic esophagitis + any of these 3 atopic diseases had significantly higher peripheral eosinophil counts and higher IgE levels.

Frequently hematoeosinophilia (5-50%), IgE elevated (in up to 70% of patients - see before).

Clinical symptomatology

Haematoeosinophilia (in 5-50% of cases), increased total IgE (70% of cases).

Endoscopy of the upper intestinal tract with bioptic clarification (detection of >15 eosinophilic granulocytes per HPF (High Power Field = visual field per 400-fold magnification).

Possible endoscopic findings: reddish longitudinal furrows, crepe paper mucosa = inelastic fragile mucosa, through solitary or multiple rings (detectable in 82% of patients) the esophagus receives a trachea-like aspect, administration of proton pump inhibitors (PPI); 2/3 of patients with EoE do not respond to PPI.

Gastroesophageal reflux (K21.9);

malignancies;

motility disorders e.g. in progressive systemic scleroderma (M34.0).

Therapeutically, the so-called "3 Ds" (diet - allergen avoidance, drugs (topical application of Budenoside sprays), dilatation (for fixed fibrostenoses) are possible. Systemic therapy with glucocorticoids in case of resistance to therapy.

A two-food-group elimination (gluten-containing cereals, milk) leads to a remission of esophagitis in around 40% of patients (Molina-Infante et al. 2018)

Medication, diet and dilation are the main treatments for EoE. Medication and diet reduce EoE-associated inflammation, and dilation targets esophageal strictures and narrowing. The choice of treatment is based on patient preference, clinical features and cost. Therapeutic goals include clinical and histologic improvement and a reduction in long-term complications. There are no Food and Drug Administration (FDA) approved medications for EoE, so in the United States all medications are used "off label".

Dietary changes are important; however, the disease usually returns when the intervention is discontinued.

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