Case Presentation:
A 31-year-old African American woman with past medical history of hypertension (HTN), gastro esophageal reflux disease (GERD), bronchial asthma and a diagnosis of Irritable Bowel Syndrome (IBS) for 10 years presented with complaints of exacerbation of chronic abdominal pain and non-bloody diarrhea for 2 weeks prior to presentation. Physical examination was unremarkable except for moderate upper abdominal tenderness. Laboratory studies were also unremarkable except for peripheral eosinophilia of 860 cells/microliter (0-450 cells/microliter). Computerized tomographical scan (CT scan) of the abdomen was unremarkable and stool studies did not reveal an infectious process. The patient underwent a diagnostic colonoscopy that showed a normal colonic mucosa but patchy erythema and multiple erosions of the cecal mucosa. Histopathology of colonic mucosa revealed dense eosinophilic infiltrates in the epithelium and lamina propria in 3 of the 5 random biopsies. Initial treatment consisted of a trial of elemental diet that had to be discontinued because of intolerance. This was followed by oral steroid therapy resulting in good clinical response.
Discussion:
Eosinophilic Colitis (EC) is the least frequent manifestation of a spectrum of gastrointestinal disorders known as Primary eosinophilic gastrointestinal disorders (EGID) where eosinophils infiltrate the gut mucosa without a known cause. The exact etiology of EC remains unclear although non-IgE mediated food allergy has been proposed as a mechanism. Clinical presentation varies depending on the colonic layer involved. Mucosal involvement presents with diarrhea and malabsorption. Whereas, transmural disease presents with obstruction due to bowel wall thickening and serosal infiltration presents with ascites. Diagnosis of EC is that of exclusion wherein secondary causes such as parasitic colitis, inflammatory bowel disease, hypereosinophilic syndrome, drug induced colitis, radiation colitis and rarely vasculitis have to be ruled out. Endoscopy may reveal mucosal edema with patchy erythema and ulcerations. Mucosal biopsies typically show eosinophilic infiltration of the lamina propria with extension through the muscularis mucosa and submucosa. Given the lack of clinical trials, treatment is based on clinical case reports and includes elimination diet and corticosteroids. The role of anti-histamines, leukotriene receptors antagonists and biologics is yet to be established in EC.
Conclusions:
Patients with EC can have presenting features that mimic IBS. Hence, a thorough diagnostic workup, including colonoscopy and biopsy is required to make an accurate diagnosis. Nevertheless, the diagnosis still requires exclusion of secondary causes and remains challenging due to the absence of clear diagnostic criteria.