What causes burps that taste like eggs?

Burps Tasting Like Eggs: Hydrogen Sulfide Production

Burps that taste like rotten eggs are caused by hydrogen sulfide gas production, most commonly from bacterial fermentation of sulfur-containing foods in the gastrointestinal tract, with underlying conditions like GERD, small intestinal bacterial overgrowth (SIBO), gastroparesis, or gastrointestinal infections (particularly Giardia) being the primary culprits. 1

Primary Mechanisms

Hydrogen sulfide gas production occurs through several pathways:

• Bacterial overgrowth: SIBO increases sulfate-reducing bacteria that produce excess hydrogen sulfide, creating the characteristic rotten egg taste 1
• Delayed gastric emptying: Gastroparesis allows prolonged bacterial fermentation of sulfur-containing foods in the stomach, increasing sulfur gas production 1
• GERD-related gastric belching: Spontaneous transient relaxation of the lower esophageal sphincter allows gas transport from the stomach through the esophagus, which can occur in up to 50% of GERD patients 1, 2
• Gastrointestinal infections: Giardia lamblia and other infections alter gut microbiota and increase sulfur gas production 1

When to Seek Medical Evaluation

Immediate evaluation is warranted if:

• Sulfur burps occur more than 3 days per week and disrupt usual activities 1
• Weight loss is present, particularly if age ≥55 years 1
• Chronic diarrhea or constipation accompanies the symptoms 1
• Severe abdominal pain or bloating is present 1
• Nausea and vomiting suggest possible gastroparesis 1

Diagnostic Approach

Testing should be targeted based on clinical presentation:

• H. pylori testing: Stool or breath testing should be offered, as this infection alters gastric function and contributes to dyspeptic symptoms 1, 3
• Breath testing: Hydrogen, methane, and CO₂ measurement can diagnose carbohydrate intolerances or SIBO in patients with persistent symptoms 1
• High-resolution esophageal manometry with impedance: Differentiates gastric belching from supragastric belching if excessive belching is the primary complaint 1, 3

Treatment Algorithm

First-Line Dietary Modifications

• Reduce high-sulfur foods for a 2-week trial to assess symptom resolution (eggs, meat, cruciferous vegetables, garlic, onions) 1
• Avoid sugar alcohols and sorbitol which increase bacterial fermentation 1
• Consider carbohydrate restriction if fructose or lactose intolerance is suspected 1

Pharmacologic Treatment Based on Underlying Cause

For GERD-related gastric belching:

• Start PPI therapy (omeprazole 20 mg daily) if GERD-related gastric belching is present 1
• Combine with diaphragmatic breathing techniques to reduce excessive belching 1

For confirmed SIBO:

• Antibiotic therapy with rifaximin or alternatives like metronidazole may be considered, though careful patient selection is needed as these are not FDA-approved for this indication 1

For H. pylori infection:

• Eradicate with appropriate antibiotic regimen if testing is positive 1, 3

Behavioral Interventions

• Diaphragmatic breathing techniques can reduce excessive belching, particularly for supragastric belching 1, 3
• Brain-gut behavioral therapy may benefit patients with excessive belching that reduces quality of life 1

Important Clinical Pitfalls

Do not confuse supragastric belching with gastric belching: Supragastric belching involves air being drawn into the esophagus and immediately expelled before reaching the stomach, is more commonly associated with anxiety, and does not respond to PPIs 3, 1. High-resolution manometry with impedance can differentiate these if the diagnosis is unclear 3.

Avoid empiric PPI therapy without GERD: PPIs are ineffective for supragastric belching not associated with reflux episodes, as the reflux episodes are usually non-acidic 4. Target the specific underlying mechanism rather than treating all belching with acid suppression.

Consider structural causes: Hiatal hernias and paraesophageal hernias can contribute to belching symptoms and may require different management 2, 3.