What are the subtypes and treatment options for microscopic colitis?

From the Guidelines

Microscopic colitis has two main subtypes: lymphocytic colitis and collagenous colitis, and the primary goal of treatment is to relieve symptoms and improve quality of life while minimizing drug-related adverse effects, as stated in the American Gastroenterological Association Institute guideline on the medical management of microscopic colitis 1.

Subtypes of Microscopic Colitis

• Lymphocytic colitis is characterized by increased intraepithelial lymphocytes
• Collagenous colitis features a thickened subepithelial collagen band

Treatment Options

• First-line pharmacological treatment is budesonide, an oral corticosteroid with minimal systemic absorption, typically prescribed at 9 mg daily for 8 weeks, followed by a taper over 2-4 weeks, as recommended by the AGA guideline 1
• For mild cases, antidiarrheals like loperamide (2-4 mg up to four times daily) or bismuth subsalicylate (eight 262 mg tablets daily for 8 weeks) may suffice
• Second-line options include cholestyramine (4 g up to three times daily), which binds bile acids, or mesalamine (2.4-4.8 g daily)
• For steroid-dependent or refractory cases, immunomodulators such as azathioprine (50-150 mg daily) or biologics like anti-TNF agents may be considered, as suggested in the guideline 1
• Dietary modifications including gluten-free or low-FODMAP diets help some patients
• Surgery with ileostomy is rarely needed for severe, treatment-resistant cases

Key Recommendations

• The AGA recommends treatment with budesonide over no treatment for the induction of clinical remission in patients with symptomatic microscopic colitis, with a strong recommendation and moderate quality of evidence 1
• The AGA also recommends treatment with budesonide over mesalamine for the induction of clinical remission, with a strong recommendation and high quality of evidence 1
• For patients with recurrence of symptoms following discontinuation of induction therapy, the AGA recommends budesonide for maintenance of clinical remission, with a strong recommendation and moderate quality of evidence 1

From the Research

Subtypes of Microscopic Colitis

• Collagenous colitis: characterized by a thickening of the subepithelial collagen layer 2
• Lymphocytic colitis: characterized by an increase of the density of intra-epithelial lymphocytes in the surface epithelium 2

Treatment Options for Microscopic Colitis

• Budesonide: effective for inducing and maintaining clinical and histological responses in patients with collagenous colitis and lymphocytic colitis 3, 4
• Antidiarrheals (e.g. loperamide): used for mild symptoms 4, 5
• Immunomodulators: may be required in rare cases 4
• Systemic glucocorticoids: reserved for patients unable to take budesonide 5
• Other medications: cholestyramine, bismuth salicylate, antibiotics, probiotics, aminosalicylates, and anti-tumor necrosis factor-alpha inhibitors may be tried in glucocorticoid refractory disease 5

Approach to Treatment

• Similar approach for both lymphocytic colitis and collagenous colitis 4
• Guided by the severity of the patient's symptoms 4
• Offending medications should be eliminated as clinically possible 4, 5
• Stepwise approach to therapy often leads to satisfactory control of symptoms 6