Eosinophilic Duodenitis

Eosinophilic duodenitis is eosinophilic infiltration of the duodenum in the absence of a secondary cause. It is a rare eosinophilic gastrointestinal disorder, often with gastric involvement and a presentation resembling peptic ulcer disease or functional dyspepsia.

It occurs at any age, commonly in young adults and children, with a slight male predominance and frequent atopy. Isolated duodenal disease is less common than combined gastric and duodenal disease.

Pathophysiology.

Allergen driven type 2 inflammation recruits eosinophils into the mucosa, muscle layer or serosa. Mucosal disease causes malabsorption, muscular disease causes obstruction, and serosal disease causes ascites.

Epigastric pain, nausea, vomiting, diarrhoea, weight loss, anaemia from malabsorption or bleeding, and gastric outlet or proximal obstruction. Ascites occurs in the serosal form.

Red flags.

• Obstructive symptoms.
• Ascites.
• Bleeding.
• Marked weight loss.

Upper endoscopy with biopsies of stomach and duodenum (including distal duodenum). There is no agreed duodenal threshold; counts well over the normal mucosal range (in practice 30 or more in each of at least 3 high power fields) with clinical correlation support the diagnosis. Exclude Helicobacter pylori, parasites, Crohn disease, coeliac disease, drug reactions, hypereosinophilic syndrome and eosinophilic granulomatosis with polyangiitis. Check blood eosinophils, IgE, stool for parasites and Strongyloides serology.

Differential diagnosis.

• Coeliac disease.
• Giardiasis and other parasitic infection.
• Crohn disease.
• Peptic ulcer disease.
• Hypereosinophilic syndrome.
• Eosinophilic granulomatosis with polyangiitis.

Use dietary elimination and topical corticosteroid, with systemic corticosteroid for severe disease and relapse prevention by the lowest effective dose.

• Budesonide: 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 in moderate hepatic impairment and avoid in severe disease.
• 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.
• Montelukast (adjunct): 10 mg orally at night; maximum 10 mg daily; monitor mood and sleep.
• Ferrous sulphate (iron deficiency): 200 mg (65 mg elemental iron) orally once daily for 3 months after haemoglobin normalises; maximum 400 mg daily; monitor ferritin and haemoglobin; use intravenous iron if oral iron fails.

Dilate or operate for stricture and obstruction.

Monitoring. Symptoms, weight, haemoglobin and blood eosinophils every 3 months; repeat endoscopy at 8 to 12 weeks and with relapse.

Referral and escalation. Gastroenterology and allergy services.

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