Collagenous colitis (CC) is a form of inflammatory bowel disease that belongs to a group known as microscopic colitis. Unlike Crohn’s disease or ulcerative colitis, CC does not cause visible inflammation during a standard colonoscopy. Instead, it shows a thickened layer of collagen beneath the lining of the colon when viewed under a microscope. The condition’s primary symptom is chronic, watery diarrhea, which is typically non-bloody but can severely affect a person’s quality of life. Treatment follows a stepwise approach, beginning with simple adjustments and progressing to potent medications to achieve and maintain symptom remission.
Initial Management Strategies
Initial management involves non-pharmacological adjustments. Patients are advised to identify and eliminate potential dietary triggers, such as caffeine, dairy products, and artificial sweeteners, which can exacerbate diarrhea. Maintaining hydration is crucial to counteract the fluid loss caused by chronic watery stools.
Lifestyle modifications, especially smoking cessation, are strongly recommended, as smoking is a significant risk factor that can increase disease severity. For immediate symptom control, over-the-counter anti-diarrheal agents like Loperamide can reduce stool frequency. These agents provide symptomatic relief but do not treat the underlying inflammation or induce histological healing. Medications known to potentially trigger CC, such as nonsteroidal anti-inflammatory drugs (NSAIDs) or certain proton pump inhibitors, should be reviewed and discontinued if possible.
Standard Pharmacological Treatments
If initial strategies fail, prescription medication is introduced to address inflammation. The first-line treatment for inducing remission is the corticosteroid Budesonide. This medication acts locally within the gastrointestinal tract and has a high first-pass metabolism in the liver.
This unique property means Budesonide is effective at the site of inflammation but has minimal systemic absorption. This significantly reduces the risk of long-term steroid-related side effects compared to traditional corticosteroids. Induction dosing typically involves 9 milligrams (mg) daily for six to eight weeks, which has demonstrated high efficacy in clinical trials.
Mesalamine (a 5-aminosalicylate, or 5-ASA) may be considered in milder cases or for patients who cannot tolerate Budesonide. However, studies show Mesalamine is consistently less effective than Budesonide for active CC. Treatment success is defined by achieving clinical remission, typically considered three or fewer bowel movements per day.
Advanced Therapies for Non-Responsive Cases
A small minority of patients (often less than 5%) may not achieve remission with Budesonide or relapse immediately, classifying their condition as refractory collagenous colitis. These individuals require a step-up approach involving more potent immunosuppression to control chronic inflammation. Treatment may escalate to conventional immunosuppressants, such as Azathioprine or Methotrexate, which suppress the overall immune response.
These medications are reserved for cases where local steroid therapy has failed, as they carry a greater risk of systemic side effects and require careful monitoring. For the most severe, non-responsive cases, biologic agents may be considered. These drugs target specific components of the inflammatory process, such as anti-tumor necrosis factor (anti-TNF) therapies like Infliximab or Adalimumab.
Janus kinase (JAK) inhibitors are also emerging as a potential advanced therapy option, based on limited case evidence. Surgical intervention, typically a colectomy, remains the last resort for CC. This procedure is only considered for patients with profoundly debilitating symptoms who have failed all available medical therapies.
Long-Term Monitoring and Relapse Prevention
Once clinical remission is achieved, the focus shifts to preventing symptom recurrence following the discontinuation of induction therapy. For patients with frequently recurring symptoms, maintenance therapy is instituted using a lower dose of Budesonide, typically 3 mg to 6 mg daily or on an alternate-day schedule. This low-dose regimen is effective for maintaining remission for at least one year in most CC patients.
The natural course of collagenous colitis involves periods of remission followed by relapse, making ongoing communication with a gastroenterologist important. Patients should recognize early signs of a relapse, such as increasing stool frequency or abdominal pain, to allow for prompt re-initiation of treatment. While symptom resolution is the primary goal, follow-up colonoscopies with biopsies may be recommended to confirm mucosal or histological healing, which is a strong predictor of long-term clinical remission.