Skip to main content



Ulcerative colitis with concomitant salmonella enteritis


Inflammatory bowel disease (IBD) comprises a spectrum of idiopathic chronic relapsing autoinflammatory diseases unified by involvement of the gastrointestinal tract. For management purposes, IBD is defined as two clinical entities, ulcerative colitis (UC) and Crohn’s disease. UC primarily affects the colon, whereas Crohn’s disease may affect any part of the GI tract, yet most frequently involving the terminal ileum. Patients with IBD present with abdominal pain, diarrhea, and bloody stools admixed with mucus, which often prompts endoscopic evaluation. Colonic biopsies from IBD patients show irregular crypt architecture with active and chronic inflammation throughout the lamina propria, including basilar plasmacytosis. The etiology is not fully understood, however, literature suggests IBD is due to dysregulation of the immune system as a result of genetic and environmental factors.

Salmonellosis manifests as colicky abdominal pain and diarrhea, which may include bloody stools - a clinical presentation similar to IBD. Humans become infected by Salmonella via the fecal-oral route after the consumption of contaminated foods such as undercooked meat or eggs, or by contact with animal reservoirs. Patients are usually diagnosed with Salmonellosis based on signs and symptoms; however, when the clinical picture is less clear, a positive stool PCR is reassuring. Histologically, infections with these bacteria may demonstrate a diffuse mixed mononuclear cell infiltrate, Peyer patch hyperplasia, crypt atrophy/disarray, ulceration, and necrosis - a histologic appearance difficult to distinguish from IBD. Differentiating between IBD and Salmonellosis becomes even harder when the Salmonella infection involves the terminal ileum, as a misdiagnosis of Crohn’s disease may be given.

In conclusion, we describe a case of UC with superimposed Salmonella infection, highlighting the importance of stool pathogen tests in patients with suspected and known IBD. Pathologists should be cognizant of potential IBD mimics such as Salmonellosis, especially when the patient is not responding to IBD therapy. 

Go Back


Kressner, M.S., et al., Salmonellosis complicating ulcerative colitis. Treatment with trimethoprim-sulfamethoxazole. JAMA, 1982. 248(5): p. 584-5.

Loftus, E.V., Jr., Clinical epidemiology of inflammatory bowel disease: Incidence, prevalence, and environmental influences. Gastroenterology, 2004. 126(6): p. 1504-17.

Pascual, V., et al., Inflammatory bowel disease and celiac disease: overlaps and differences. World J Gastroenterol, 2014. 20(17): p. 4846-56.

Sarigol, S., et al., Inflammatory bowel disease presenting as Salmonella colitis: the importance of early histologic examination in recognition and management. Clin Pediatr (Phila), 1999. 38(11): p. 669-72.

Schultz, B.M., et al., A Potential Role of Salmonella Infection in the Onset of Inflammatory Bowel Diseases. Front Immunol, 2017. 8: p. 191.