Lymphocytic colitis (LC) is an inflammatory bowel condition affecting the large intestine, or colon. It is classified under the broader term Microscopic Colitis, alongside Collagenous Colitis. Both forms of Microscopic Colitis are characterized by inflammation of the colon that is only visible when tissue samples are examined under a microscope. LC is defined by a specific accumulation of white blood cells within the colon’s lining.
Recognizing the Signs
The defining clinical manifestation of lymphocytic colitis is chronic, watery, and typically non-bloody diarrhea. This persistent diarrhea is frequent, with many individuals experiencing between five and ten watery bowel movements daily. The severity of this diarrhea significantly impacts daily life, often leading to a sense of urgency and sometimes fecal incontinence.
Patients often report accompanying symptoms such as abdominal discomfort, cramping, and bloating. Although the condition does not cause the severe inflammation seen in other types of inflammatory bowel disease, the symptoms can still be debilitating. The constant strain and fluid loss from frequent bowel movements contribute to fatigue.
Prolonged, severe diarrhea can lead to secondary complications like dehydration. Some patients may experience unintended weight loss due to chronic malabsorption or reduced food intake associated with managing symptoms. These symptoms often wax and wane, cycling between periods of flare-up and remission.
Understanding the Root Causes
The precise cause of lymphocytic colitis is often described as idiopathic, meaning the exact trigger remains unclear. Current research suggests the condition results from an abnormal immune response within the colon. This process involves the immune system mistakenly attacking the body’s own cells in the intestinal lining.
This hypothesis is supported by the strong association between lymphocytic colitis and other autoimmune disorders. Individuals diagnosed with LC frequently have a concurrent diagnosis of conditions such as Celiac disease or thyroid disorders. Up to 60% of patients with LC may present with another autoimmune disease, suggesting a shared underlying susceptibility.
Certain medications are strongly linked to the onset or exacerbation of lymphocytic colitis symptoms. Common culprits include Nonsteroidal Anti-inflammatory Drugs (NSAIDs), such as ibuprofen and aspirin, which irritate the gut lining. Proton Pump Inhibitors (PPIs), commonly used to treat acid reflux, have also been associated with the condition.
In addition to NSAIDs and PPIs, certain types of antidepressants, specifically Selective Serotonin Reuptake Inhibitors (SSRIs), are recognized triggers. These substances potentially disrupt the balance of the gut lining, leading to the characteristic inflammatory response. Environmental factors, such as cigarette smoking, also increase the risk of developing the condition.
How Doctors Confirm the Diagnosis
Lymphocytic colitis is grouped with Microscopic Colitis because the inflammation is not visible during an endoscopy. A routine colonoscopy, which uses a flexible tube and camera to examine the colon, typically shows a lining that appears normal or only mildly irritated. This lack of visible damage often leads to the condition being initially misdiagnosed as Irritable Bowel Syndrome (IBS).
Because the colon appears visually healthy, the diagnosis of LC requires a biopsy, which is considered the gold standard procedure. During the colonoscopy, the doctor takes multiple tissue samples from various segments of the colon. These samples are then sent to a pathology lab for examination.
The pathologist analyzes the tissue to determine the degree of inflammatory cell infiltration. The defining characteristic of lymphocytic colitis is a significant increase in lymphocytes (a specific type of white blood cell) within the colonic epithelium. Diagnosis is confirmed when the count exceeds 20 intraepithelial lymphocytes per 100 epithelial cells.
This finding differentiates LC from Collagenous Colitis, the other subtype of Microscopic Colitis. Collagenous Colitis is defined by a thickened layer of collagen beneath the epithelium, a feature absent in lymphocytic colitis. The microscopic analysis is the only way to distinguish between these two causes of chronic watery diarrhea.
Treatment Pathways and Long-Term Management
The initial phase of managing lymphocytic colitis involves identifying and removing potential triggers. Discontinuing associated medications, such as NSAIDs, PPIs, or SSRIs, often leads to symptom reduction or resolution. A healthcare provider will work to safely substitute or eliminate these agents where possible, which is a foundational step in management.
For patients experiencing moderate to severe symptoms, the first-line medication is the corticosteroid Budesonide. Budesonide is formulated to act topically within the gut with minimal systemic absorption, treating the inflammation locally. This targeted delivery helps reduce the risk of common steroid side effects seen with conventional corticosteroids.
The standard regimen for inducing remission involves a dosage of 9 milligrams of Budesonide taken daily for six to eight weeks. Studies show this treatment induces clinical remission in a majority of patients, often providing rapid relief from severe diarrhea. After symptoms resolve, the drug is gradually tapered off to prevent recurrence.
For immediate, mild symptom control, over-the-counter antidiarrheal agents like Loperamide may be used. These medications slow the movement of stool through the colon, reducing the frequency and urgency of bowel movements. Bismuth subsalicylate is another agent sometimes used for symptomatic relief.
Dietary adjustments serve as a supplementary management tool to reduce irritation. Common recommendations include temporarily reducing or eliminating caffeine, alcohol, and dairy products, which can exacerbate diarrhea. Some individuals find relief by following a low-FODMAP diet, which restricts fermentable carbohydrates that can cause gas and bloating.
Cases that do not respond to Budesonide are deemed refractory. Stronger immunosuppressive therapies, such as thiopurines or biologic agents, may be considered to control the immune response. These advanced therapies are reserved for the most challenging forms of the disease after conventional treatments have failed.