Eosinophilic Gastritis

Eosinophilic gastritis is a chronic immune mediated condition with dense eosinophilic infiltration of the stomach wall, causing dyspepsia, vomiting and weight loss. It is part of the spectrum of eosinophilic gastrointestinal disorders.

It is rare, with a prevalence of about 2 in 100,000, and occurs at any age with a peak in the third to fifth decades. Around half of patients have atopic disease (asthma, eczema, food allergy), and the course relapses and remits.

Pathophysiology.

Allergic sensitisation to food or aeroallergens drives type 2 inflammation (interleukin 4, 5 and 13, eotaxin 3), recruiting eosinophils that release toxic granule proteins, causing mucosal injury, fibrosis and dysmotility.

Epigastric pain, nausea, vomiting, early satiety, bloating, weight loss, iron deficiency anaemia and failure to thrive in children. Deep layer disease causes gastric outlet obstruction, and serosal disease causes ascites.

Red flags.

• Gastric outlet obstruction.
• Eosinophilic ascites.
• Gastrointestinal bleeding.
• Severe weight loss.

Upper endoscopy with multiple biopsies (at least 5 from the antrum and body, even from normal mucosa). Histology shows 30 or more eosinophils in each of at least 5 high power fields. Exclude secondary causes: Helicobacter pylori infection, parasites, Crohn disease, drug reaction, hypereosinophilic syndrome, vasculitis (eosinophilic granulomatosis with polyangiitis) and connective tissue disease. Check blood eosinophils, IgE, stool for parasites and serology for Strongyloides.

Differential diagnosis.

• Helicobacter pylori gastritis.
• Parasitic infection.
• Crohn disease.
• Hypereosinophilic syndrome.
• Eosinophilic granulomatosis with polyangiitis.
• Drug induced eosinophilia.

Remove triggers where known (six food elimination diet or an elemental diet in children), then use topical or systemic corticosteroids to induce remission and the lowest effective dose to maintain it. Relapse is common when treatment stops.

• Prednisolone: 0.5 to 1 mg/kg orally once daily (maximum 40 mg daily) for 2 to 4 weeks, then taper over 4 to 8 weeks; monitor glucose, blood pressure and bone health; reduce in older adults and give gastric protection.
• Budesonide (swallowed or open capsule): 9 mg orally once daily in the morning for 8 weeks, then 3 to 6 mg daily for maintenance; maximum 9 mg daily; monitor for candidiasis and adrenal suppression; reduce to 3 mg in moderate hepatic impairment and avoid in severe disease.
• Omeprazole: 20 to 40 mg orally once daily for acid symptoms; maximum 80 mg daily; monitor magnesium and symptoms; reduce to 20 mg daily in severe hepatic impairment.
• Montelukast (adjunct): 10 mg orally at night; maximum 10 mg daily; monitor mood and sleep; no renal adjustment.

Biologic agents such as dupilumab (300 mg subcutaneously weekly) are specialist options for refractory disease. Treat iron deficiency, and dilate or operate for obstruction.

Monitoring. Symptoms and weight every 3 months; repeat endoscopy and biopsies after 8 to 12 weeks of treatment and with relapse.

Referral and escalation. Gastroenterology and allergy services.

Special groups. Children need weight based dosing and dietitian support.