What are the most likely differentials for a young to middle-aged adult with no significant medical history who presents with belching, abdominal pain, and diarrhea after consuming street food?

Most Likely Differential Diagnoses for Post-Street Food Gastrointestinal Symptoms

Bacterial foodborne illness—specifically Salmonella, E. coli, Campylobacter, or Listeria—is the most likely diagnosis in this patient with belching, abdominal pain, and diarrhea following street food consumption. 1

Primary Differential Diagnoses

Bacterial Gastroenteritis (Most Likely)

• Bacterial pathogens account for the majority of foodborne illnesses following street food consumption, with the four most common organisms being Salmonella, E. coli, Campylobacter, and Listeria. 1
• Bacterial etiology is found in 5-17% of adults presenting with acute diarrhea to emergency departments, with higher likelihood when accompanied by abdominal pain—both of which this patient has. 1
• The incubation period typically ranges from hours to 2-3 days after contaminated food consumption, which fits the temporal relationship with street food intake. 1
• One in six Americans experiences a foodborne illness annually, with bacteria like Salmonella, E. coli, Campylobacter, and Listeria being the most common causes. 2

Viral Gastroenteritis (Second Most Common)

• Viruses, particularly norovirus, are major causes of acute gastroenteritis and can occur in food-borne illness outbreaks. 2, 3
• Viral gastroenteritis causes inflammation of the stomach and intestines, presenting with abdominal pain, diarrhea, nausea, and vomiting—though belching is less characteristic. 4
• The majority of acute gastroenteritis cases are self-limited and resolve without specific intervention. 5

Carbohydrate Malabsorption

• Lactose or fructose in street food ingredients can cause belching, abdominal pain, and diarrhea through osmotic effects. 1
• This mechanism explains the belching component particularly well, as gastric belching occurs in up to 50% of patients with gastritis and involves air transport from the stomach. 6

Alpha-Gal Syndrome (Geographic-Dependent)

• This diagnosis should be considered if the patient consumed mammalian meat from street vendors AND lives in tick-prevalent regions. 1
• Alpha-gal syndrome presents with GI symptoms 1-4 hours after mammalian meat consumption, including abdominal pain, diarrhea, nausea, and vomiting, often without skin or respiratory symptoms. 1
• This is frequently missed because providers fail to ask about geographic location and tick exposure in patients with delayed GI symptoms after meat consumption. 1

Clostridium difficile

• C. difficile should be tested in all new presentations of diarrhea, regardless of antibiotic exposure history, as community-acquired cases are increasing. 1
• The prevalence of C. difficile is increasing in both adult and pediatric patients. 7

Critical Diagnostic Approach

History Elements That Differentiate Diagnoses

• Timing of symptom onset relative to food consumption helps differentiate bacterial, viral, and allergic etiologies. 1
• Presence of fever and bloody diarrhea increases likelihood of invasive bacterial pathogens like Salmonella, Campylobacter, or Shigella. 1
• Geographic location and travel history matter for alpha-gal syndrome and specific bacterial pathogens. 1
• Recent antibiotic use raises concern for C. difficile, though testing should occur regardless. 1

When to Obtain Laboratory Testing

• Stool culture should be obtained if the patient has bloody diarrhea, fever, severe abdominal pain, or signs of volume depletion. 1
• Testing for C. difficile is recommended in all new presentations of diarrhea, regardless of antibiotic exposure history. 1
• Alpha-gal IgE antibody testing should be performed if the patient consumed mammalian meat and lives in or has traveled to tick-endemic regions. 1
• Diagnostic testing in less ill patients with probable viral illnesses is unrevealing and wasteful of resources. 5

Management Principles

• Preventing dehydration or providing appropriate rehydration is the primary supportive treatment. 7
• Antibiotic selection should be guided by local resistance patterns when empiric therapy is indicated. 1
• If alpha-gal syndrome is confirmed with elevated IgE, initiate strict mammalian meat avoidance diet and counsel on avoiding further tick bites. 1

Critical Pitfalls to Avoid

• Do not assume viral etiology without considering bacterial causes, especially with street food exposure and presence of fever or bloody diarrhea. 1
• Do not miss alpha-gal syndrome by failing to ask about geographic location and tick exposure in patients with delayed GI symptoms after meat consumption. 1
• Do not overlook C. difficile testing even in patients without recent antibiotic use, as community-acquired cases are increasing. 1
• Do not order extensive diagnostic testing in well-appearing patients without fever, bloody diarrhea, or volume depletion, as most cases are self-limited. 5