Management of Diarrhea in Scleroderma
Treat diarrhea in scleroderma patients with rotating antibiotics as first-line therapy to eradicate small intestinal bacterial overgrowth (SIBO), which is the primary cause of diarrhea in these patients. 1, 2
Understanding the Pathophysiology
Scleroderma causes smooth muscle atrophy and gut wall fibrosis throughout the gastrointestinal tract, leading to hypomotility, bacterial overgrowth, malabsorption, and malnutrition. 2, 3 This hypomotility creates an environment where bacteria proliferate abnormally in the small intestine, directly causing diarrhea and other gastrointestinal symptoms. 4
SIBO occurs in approximately 55% of scleroderma patients compared to less than 7% of healthy controls, making it the dominant mechanism of diarrhea in this population. 4
Primary Treatment Algorithm
Step 1: Initiate Rotating Antibiotics for SIBO
Start intermittent or rotating antibiotics immediately for symptomatic SIBO. 1, 2 The EULAR guidelines specifically recommend this as the cornerstone of management. 1, 2
- Rotate between Rifaximin, Metronidazole, and Ciprofloxacin (or other fluoroquinolones) every 1-2 weeks to prevent bacterial resistance. 1, 2
- Antibiotic therapy achieves SIBO eradication in approximately 73% of scleroderma patients, with symptomatic improvement in 73% of those successfully treated. 4
- Confirm SIBO with hydrogen breath testing when available, though treatment can be initiated based on clinical suspicion given the high prevalence. 2, 4
Step 2: Add Prokinetic Agents for Motility Disturbances
Use prokinetic drugs for symptomatic motility disturbances including diarrhea, bloating, early satiety, and pseudo-obstruction. 1, 2 While EULAR guidelines recommend prokinetics with strength of recommendation C, they acknowledge the lack of large RCTs specifically in scleroderma. 1
- Prucalopride (a 5-HT4 receptor agonist) at standard dosing has shown effectiveness in scleroderma patients, improving evacuation frequency and constipation scores. 2, 5
- Note that cisapride, while effective in small trials, has been withdrawn or restricted in many countries due to cardiac arrhythmia risk. 1
Step 3: Maintain Proton Pump Inhibitors
Continue PPIs for concurrent gastroesophageal reflux disease, which affects the majority of scleroderma patients and can contribute to overall symptom burden. 1, 2 EULAR recommends PPIs with strength of recommendation B for GERD management and prevention of esophageal complications. 1
Critical Management Pitfall
Do not use antimotility agents like loperamide in scleroderma-related diarrhea. 2 This is fundamentally different from other causes of diarrhea. Loperamide can worsen bacterial overgrowth by further slowing transit and can precipitate pseudo-obstruction or even stercoral perforation in patients with already compromised intestinal motility. 2
Refractory Cases
When First-Line Therapy Fails
Consider octreotide for refractory diarrhea at 100-150 μg subcutaneously three times daily, escalating to 500 μg three times daily as needed. 2 A systematic review found octreotide achieved the best SIBO eradication results in a small subset of patients. 1
Severe Malabsorption and Malnutrition
For severe malabsorption and malnutrition despite medical therapy, long-term parenteral nutrition can be safe and effective. 2, 6 This becomes essential when oral or enteral nutrition cannot maintain nutritional status. 2
Evidence Quality Considerations
The recommendations are based primarily on EULAR guidelines (the highest quality source for scleroderma management), though the evidence base consists mainly of small uncontrolled studies and retrospective analyses rather than large RCTs. 1 The 2025 EULAR systematic literature review confirms that antibiotics effectively eradicate SIBO, though the optimal antibiotic regimen remains based on expert opinion. 1 The combination of probiotics with antibiotics showed superior SIBO eradication (55%) compared to antibiotics alone (25%) in one small trial, though a larger RCT found no benefit of probiotics on GI symptoms. 1, 7