Eosinophilic Gastroenteritis Medical Services in China

Eosinophilic gastroenteritis (EGE) is a rare, chronic, immune-mediated gastrointestinal disorder characterized by eosinophilic infiltration of the gastrointestinal (GI) tract wall—spanning from the esophagus to the colon—without evidence of parasitic infection, malignancy, or systemic eosinophilic disease. It predominantly affects the stomach and small intestine but may involve any GI segment. Histologically, diagnosis requires ≥20 eosinophils per high-power field (HPF) in gastric or intestinal biopsies, alongside clinical symptoms and exclusion of secondary causes. Pathogenesis remains incompletely understood but involves dysregulated T-helper 2 (Th2) immune responses, aberrant cytokine signaling (notably IL-5, IL-4, and eotaxin), and antigen-driven eosinophil recruitment and activation. Genetic predisposition (e.g., polymorphisms in IL-5Rα and FCER1A), environmental triggers (food allergens such as milk, egg, wheat, soy, nuts), and impaired mucosal barrier function likely contribute synergistically. Epidemiologically, EGE is exceedingly rare, with an estimated incidence of 0.007–0.013 per 100,000 person-years and prevalence under 10 per million. It affects all ages but peaks in adults aged 30–50 years; pediatric cases are increasingly recognized. There is no strong gender predilection, though some studies report slight male predominance. Risk factors include personal or familial atopy (asthma, allergic rhinitis, eczema), food allergy history, elevated serum IgE, and peripheral eosinophilia (>500/μL). Clinical presentation varies by layer involvement: mucosal disease causes abdominal pain, nausea, vomiting, diarrhea, iron-deficiency anemia, hypoalbuminemia, and protein-losing enteropathy; muscular involvement leads to obstructive symptoms (e.g., gastric outlet obstruction, intussusception); serosal disease may present with ascites and peripheral eosinophilia. Diagnosis relies on endoscopic biopsy with histopathology, imaging (CT/MRI showing bowel wall thickening, fluid accumulation), and comprehensive workup to rule out hypereosinophilic syndrome, parasitic infestation (e.g., Strongyloides), vasculitis, lymphoma, and celiac disease. Untreated or poorly controlled EGE significantly impairs quality of life—patients frequently experience chronic fatigue, dietary restrictions, social isolation due to unpredictable GI flares, anxiety around eating, work absenteeism, and reduced physical functioning. Children may suffer growth failure and nutritional deficits. Long-term complications include strictures, malnutrition, spontaneous perforation (rare), and corticosteroid-related morbidity. Early multidisciplinary management—including allergology, nutrition support, and gastroenterology—is essential to mitigate disease burden and preserve GI integrity.

Eosinophilic gastroenteritis (EGE) is a rare, chronic, immune-mediated gastrointestinal disorder characterized by eosinophilic infiltration of the gastrointestinal (GI) tract wall—spanning from the esophagus to the colon—without evidence of parasitic infection, malignancy, or systemic eosinophilic disorders such as hypereosinophilic syndrome. The precise etiology remains incompletely understood, but current evidence supports a multifactorial pathogenesis involving dysregulated type 2 immune responses, aberrant antigen recognition, and mucosal barrier dysfunction. Common causes are not attributable to a single agent but rather reflect an abnormal host response to luminal antigens—particularly dietary proteins (e.g., cow’s milk, egg, wheat, soy, nuts, fish)—in genetically susceptible individuals. This leads to T-helper 2 (Th2) lymphocyte activation, interleukin-5 (IL-5) overexpression, and subsequent eosinophil recruitment, degranulation, and tissue injury. While no definitive infectious cause has been established, transient mucosal inflammation following viral gastroenteritis may act as a precipitating event in predisposed patients, potentially via epitope mimicry or bystander activation. Autoimmune mechanisms are suspected but unproven; no consistent autoantibodies or HLA associations have been validated across cohorts.

Triggers are predominantly exogenous and modifiable. Food allergens constitute the most clinically relevant triggers, with symptom exacerbation commonly observed after ingestion of specific proteins—confirmed via elimination diets and oral food challenges. Environmental aeroallergens (e.g., pollens, molds, house dust mites) may also contribute, particularly in patients with concomitant allergic rhinitis or asthma, suggesting shared atopic pathways. Medications—including nonsteroidal anti-inflammatory drugs (NSAIDs), antibiotics (especially broad-spectrum), and proton pump inhibitors—have been anecdotally linked to flares, possibly through disruption of microbiome homeostasis or direct mucosal irritation. Stress and acute infections can transiently amplify Th2 cytokine production and eosinophil trafficking, serving as secondary physiological triggers.

Established risk factors include personal or familial atopy: up to 70% of EGE patients report comorbid allergic conditions such as asthma, allergic rhinitis, atopic dermatitis, or IgE-mediated food allergy. Male sex confers a modest increased risk (male-to-female ratio ~1.5–2:1), particularly in adult-onset disease. Age distribution is bimodal, with peaks in childhood (ages 3–15 years) and adulthood (30–50 years), suggesting developmental and immunosenescent influences on disease expression. Chronic use of proton pump inhibitors (PPIs) is associated with an elevated risk of developing eosinophilic esophagitis (EoE), and while data for gastric/enteric involvement are less robust, PPI-responsive EGE variants suggest overlapping pathophysiological mechanisms related to acid suppression-induced mucosal remodeling and altered antigen exposure.

Genetic factors play a permissive, rather than deterministic, role. Genome-wide association studies (GWAS) are limited due to disease rarity, but candidate gene analyses implicate polymorphisms in Th2 pathway genes—including IL5RA (encoding the alpha subunit of the IL-5 receptor), TSLP (thymic stromal lymphopoietin), and STAT6 (signal transducer and activator of transcription 6). Variants in the filaggrin gene (FLG), strongly associated with atopic dermatitis and epithelial barrier defects, may confer susceptibility via impaired GI mucosal integrity. Familial clustering is reported but uncommon; monozygotic twin concordance is low, reinforcing that genetics alone are insufficient for disease manifestation.

Environmental factors significantly modulate risk. Early-life exposures—including cesarean delivery, antibiotic exposure in infancy, and reduced microbial diversity—may impair immune tolerance development and increase susceptibility. Urban residence and higher socioeconomic status correlate with increased prevalence, likely reflecting the ‘hygiene hypothesis’ and reduced early-life microbial exposure. Dietary patterns high in processed foods and low in fiber may alter gut microbiota composition (dysbiosis), diminishing regulatory T-cell function and promoting eosinophilic inflammation. Air pollution (e.g., PM2.5, NO2) has been associated with heightened systemic Th2 inflammation and may exacerbate GI eosinophilia in sensitized individuals. Notably, geographic variation exists: higher incidence rates are reported in North America and Western Europe compared with Asia, though diagnostic ascertainment bias cannot be excluded. Importantly, no causal link has been demonstrated between vaccination history and EGE development. In summary, EGE arises from complex interactions among genetic susceptibility, environmental exposures, dietary antigens, and immune dysregulation—making it a paradigm of gene–environment–microbiome interplay in mucosal immunology.

Eosinophilic gastroenteritis (EGE) is a rare, chronic, heterogeneous inflammatory disorder of the gastrointestinal (GI) tract characterized by eosinophilic infiltration of one or more layers of the GI wall—mucosal, muscular, or serosal—in the absence of known secondary causes such as parasitic infection, malignancy, drug reaction, or systemic eosinophilic disorders (e.g., hypereosinophilic syndrome, Churg-Strauss syndrome). It predominantly affects adults aged 30–50 years, with a slight male predominance, though pediatric cases occur. Clinical presentation varies significantly depending on the depth and extent of eosinophilic infiltration, leading to three overlapping phenotypic subtypes: mucosal (most common), muscular, and serosal. Early symptoms are often nonspecific and insidious, contributing to frequent diagnostic delays averaging 2–5 years from symptom onset. Patients commonly report intermittent abdominal discomfort, early satiety, postprandial bloating, and mild nausea—symptoms frequently misattributed to functional dyspepsia or irritable bowel syndrome. A subset may experience recurrent, self-limiting episodes of vomiting or loose stools without overt blood or fever, further delaying suspicion of organic disease. Pruritus or urticarial skin lesions may precede GI symptoms in atopic individuals, reflecting underlying Th2-mediated immune dysregulation.

Typical symptoms reflect the anatomical layer involved. In mucosal-dominant EGE, the hallmark manifestations include protein-losing enteropathy—evidenced by hypoalbuminemia, peripheral edema, and ascites—and malabsorption syndromes presenting as steatorrhea, weight loss (>10% body weight over 6 months), iron-deficiency anemia (due to chronic mucosal bleeding or impaired iron absorption), and deficiencies of fat-soluble vitamins (A, D, E, K) and vitamin B12. Upper GI involvement often manifests as epigastric pain, nausea, vomiting (sometimes bilious or containing undigested food), and hematemesis or melena if ulceration or erosions develop. Lower GI involvement may cause chronic diarrhea, tenesmus, and occasionally hematochezia. Muscular-layer infiltration leads to obstructive physiology: patients develop colicky abdominal pain, nausea, vomiting, and signs of partial small bowel obstruction—including visible peristalsis, high-pitched bowel sounds, and radiographic evidence of dilated loops with air-fluid levels. Intussusception and gastric outlet obstruction are recognized complications, particularly with focal hypertrophy of the pylorus or duodenum. Serosal involvement is least common but most dramatic: it presents with acute or recurrent eosinophilic ascites—often exudative, with elevated peritoneal fluid eosinophils (>500/μL or >10% of nucleated cells), normal glucose, low lactate dehydrogenase, and negative cultures. Ascites may be massive and refractory to diuretics, mimicking malignancy or liver disease. Rarely, serosal disease extends to involve the pleura (eosinophilic pleural effusion) or pericardium.

Accompanying symptoms underscore the systemic and allergic nature of EGE. Approximately 50–75% of patients have personal or family history of atopy—asthma, allergic rhinitis, eczema, or food allergy. Elevated serum IgE (>150 IU/mL) is present in ~60% of cases, though not diagnostic. Peripheral eosinophilia (>500/μL) occurs in 40–80% of patients but may be absent in localized or corticosteroid-treated disease. Other associated features include fatigue (secondary to anemia, hypoalbuminemia, or chronic inflammation), arthralgias, and low-grade fevers. Some patients report reproducible symptom exacerbations following ingestion of specific foods (e.g., milk, egg, wheat, soy, nuts), supporting an IgE- or T-cell–mediated food hypersensitivity mechanism.

Complications arise from chronic inflammation, tissue remodeling, and therapeutic interventions. Strictures and fibrosis may develop after repeated inflammatory episodes, especially in muscular or transmural disease, necessitating endoscopic dilation or surgical resection. Chronic protein loss predisposes to spontaneous bacterial peritonitis (particularly with ascites), thromboembolic events (due to hypoalbuminemia-induced hypercoagulability and acquired antithrombin III deficiency), and increased susceptibility to infections. Long-standing malnutrition contributes to osteopenia, muscle wasting, and growth failure in children. Corticosteroid therapy—first-line treatment—carries risks of diabetes mellitus, hypertension, cataracts, avascular necrosis, and adrenal suppression. Rarely, EGE may evolve into lymphoproliferative disorders or exhibit clonal eosinophil expansion, warranting hematologic evaluation.

Diagnosis requires integration of clinical, laboratory, imaging, endoscopic, and histopathologic findings. No single test is definitive. Initial workup includes complete blood count (to assess eosinophilia), comprehensive metabolic panel (hypoalbuminemia, electrolyte imbalances), serum IgE, stool studies (ova and parasite testing, culture, calprotectin), and celiac serology (tTG-IgA, EMA) to exclude mimics. Endoscopy with extensive biopsies is mandatory: at least 6–8 biopsies should be obtained from multiple sites (esophagus, stomach, duodenum, terminal ileum, colon), as eosinophilic infiltration can be patchy. Histologic diagnosis requires ≥20 eosinophils per high-power field (HPF) in the lamina propria (mucosal subtype), or transmural infiltration with eosinophils extending into muscularis propria or serosa. Immunohistochemistry (e.g., CD117, tryptase) helps distinguish eosinophils from mast cells; eosinophil peroxidase staining enhances detection sensitivity. Cross-sectional imaging—CT or MRI abdomen—may reveal mural thickening, fold enlargement, luminal narrowing, mesenteric stranding, or ascites. Capsule endoscopy or double-balloon enteroscopy aids evaluation of the small bowel beyond standard endoscopy reach. Serological exclusion of parasitic infections (Strongyloides stercoralis, Ascaris, hookworm via ELISA or PCR) and malignancy (CT/PET-CT, bone marrow biopsy if systemic symptoms or marked eosinophilia) is essential.

Differential diagnosis is broad and must systematically exclude secondary eosinophilic GI disorders. Key entities include parasitic infestations (especially Strongyloides, which can cause life-threatening hyperinfection in immunocompromised hosts); drug-induced eosinophilic gastroenteritis (e.g., NSAIDs, antibiotics, PPIs); inflammatory bowel disease (IBD)—particularly Crohn’s disease with eosinophil-rich granulomas or ulcerative colitis with prominent eosinophilia; celiac disease (which may show increased intraepithelial lymphocytes and eosinophils but lacks transmural eosinophilic infiltration); vasculitides (eosinophilic granulomatosis with polyangiitis, formerly Churg-Strauss); hypereosinophilic syndrome (HES) with GI involvement; lymphoma (especially T-cell lymphoma or Hodgkin lymphoma); and gastric adenocarcinoma or lymphoma-associated eosinophilia. Unlike EGE, IBD typically shows crypt architectural distortion and basal plasmacytosis; celiac disease demonstrates villous atrophy and intraepithelial lymphocytosis without dominant eosinophilic infiltration; and HES exhibits clonal eosinophilia, organ damage beyond GI tract (cardiac, pulmonary, neurologic), and often elevated serum tryptase or FIP1L1-PDGFRA fusion gene. Accurate differentiation hinges on meticulous history (travel, medications, atopy), targeted serologic and microbiologic testing, histopathologic pattern analysis, and multidisciplinary correlation among gastroenterologists, pathologists, allergists, and hematologists.

Eosinophilic gastroenteritis (EGE) is a rare, chronic, immune-mediated disorder characterized by eosinophilic infiltration of the gastrointestinal (GI) tract in the absence of parasitic infection, malignancy, or systemic eosinophilic disease. Diagnosis requires histopathological confirmation of ≥20 eosinophils per high-power field (HPF) in gastric or intestinal biopsies, coupled with clinical symptoms such as abdominal pain, diarrhea, nausea, vomiting, early satiety, weight loss, and occasionally protein-losing enteropathy or obstructive features. Management is multidisciplinary and tailored to disease extent (mucosal, muscular, or serosal), symptom severity, and endoscopic/histologic findings. Treatment strategies fall into three broad categories: conservative (dietary and lifestyle), pharmacologic, and surgical—each employed sequentially or in combination based on response and complications.

Conservative treatment serves as the cornerstone for mild-to-moderate mucosal-predominant EGE and is especially critical in pediatric and young adult patients. Elimination diets—most rigorously the six-food elimination diet (SFED: excluding cow’s milk, soy, wheat, egg, peanut/tree nuts, and seafood)—are first-line non-pharmacologic interventions. Evidence supports SFED-induced histologic remission in up to 75% of responsive patients within 6–8 weeks. Elemental diets (amino acid-based formulas) are reserved for refractory cases or severe malnutrition, particularly in children, achieving remission rates exceeding 85% but with significant adherence challenges. Nutritional counseling by registered dietitians specializing in eosinophilic GI disorders is mandatory to prevent micronutrient deficiencies (e.g., vitamin D, calcium, iron, B12) and ensure caloric adequacy. Patients are advised to maintain food/symptom diaries and undergo periodic nutritional assessment. Lifestyle modifications include stress reduction (given neuroimmune interactions), avoidance of NSAIDs (which may exacerbate mucosal inflammation), and smoking cessation (smoking correlates with increased eosinophil activation).

Pharmacotherapy is initiated when conservative measures fail, symptoms are moderate-to-severe, or extraintestinal manifestations (e.g., peripheral eosinophilia >1,500/μL, ascites) are present. Corticosteroids remain the most effective induction agents: oral budesonide (9 mg/day for adults, weight-adjusted in children) offers targeted mucosal anti-inflammatory action with markedly reduced systemic exposure compared to prednisone. For diffuse or deep-layer involvement, short-course systemic corticosteroids (prednisone 0.5–1 mg/kg/day for 2–4 weeks, followed by taper over 8–12 weeks) are preferred. Maintenance therapy may involve low-dose budesonide or leukotriene receptor antagonists (e.g., montelukast 10 mg daily), though evidence for long-term monotherapy is limited. Biologics represent a paradigm shift for steroid-dependent or refractory EGE. Mepolizumab, benralizumab, and dupilumab have demonstrated efficacy in case series and small trials by targeting IL-5 or IL-4/IL-13 pathways—key drivers of eosinophilopoiesis and tissue recruitment. Dupilumab (300 mg SC weekly after loading dose) shows particular promise in patients with concurrent atopic comorbidities. Other immunomodulators—including azathioprine (2–2.5 mg/kg/day) and methotrexate (15–25 mg/week)—may be considered for steroid-sparing maintenance, though data are extrapolated from eosinophilic esophagitis and require careful monitoring for hepatotoxicity and myelosuppression.

Surgical intervention is rarely indicated and reserved exclusively for life-threatening complications. These include acute intestinal obstruction due to muscularis propria hypertrophy, perforation secondary to ulceration or necrosis, massive hemorrhage unresponsive to endoscopic control, or intractable protein-losing enteropathy with recurrent ascites refractory to medical therapy. Procedures range from segmental resection (e.g., ileal or colonic resection) to partial gastrectomy in severe gastric involvement. Laparoscopic approaches are favored where feasible to minimize postoperative morbidity. Surgery does not address the underlying immune dysregulation; thus, perioperative corticosteroid coverage and prompt resumption of medical therapy are essential to prevent recurrence in adjacent or residual mucosa.

China offers distinct advantages in EGE management, rooted in integrated healthcare infrastructure and rapidly evolving expertise. Major tertiary hospitals—such as Peking Union Medical College Hospital, West China Hospital, and Shanghai Renji Hospital—host dedicated eosinophilic GI disease centers with multidisciplinary teams (gastroenterologists, allergists, pathologists, dietitians, and clinical immunologists). These centers utilize standardized histopathologic protocols, including eosinophil quantification via digital pathology platforms and rigorous exclusion criteria for parasitic infections (e.g., stool PCR for Strongyloides, serum IgE against Ascaris/Taenia). Access to biosimilars and domestically manufactured biologics (e.g., dupilumab biosimilars approved under NMPA guidelines) significantly reduces treatment cost versus Western markets. Furthermore, China’s national real-world evidence initiatives (e.g., the China Eosinophilic GI Disease Registry) facilitate rapid data aggregation on treatment responses, enabling personalized algorithms. Traditional Chinese Medicine (TCM) adjuncts—such as modified Si Jun Zi Tang or Shen Ling Bai Zhu San—are increasingly studied in randomized controlled trials for symptom modulation and steroid-sparing effects, though they are never used as monotherapy and always under integrated supervision.

Recovery and long-term management emphasize vigilant monitoring and patient empowerment. Patients should undergo repeat upper/lower endoscopy with systematic biopsies every 3–6 months during active treatment and annually in sustained remission to assess histologic response—clinical improvement alone is insufficient. Laboratory surveillance includes CBC with differential, albumin, IgE, and liver/kidney function tests. Vaccination status (especially pneumococcal and influenza) must be optimized prior to immunosuppression. Psychological support is integral: chronic GI symptoms correlate strongly with anxiety and depression, and cognitive behavioral therapy has shown benefit in symptom perception and coping. Patients are counseled that EGE is typically relapsing-remitting; however, with structured care, >80% achieve durable remission (>2 years) without disability. Pregnancy planning warrants preconception optimization, as uncontrolled disease increases risks of fetal growth restriction. Finally, patients should carry emergency steroid cards and receive clear written action plans for symptom flares—including when to seek urgent evaluation for signs of obstruction (bilious vomiting, absolute constipation) or ascites progression. Through coordinated, evidence-informed, and culturally attuned care, EGE can be effectively managed as a chronic but controllable condition.