What causes Ulcerative Colitis (UC)?

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Last updated: February 25, 2025View editorial policy

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From the Guidelines

The exact cause of ulcerative colitis is unknown, but it's believed to result from a complex interaction of genetic, environmental, and immune system factors, with the immune system abnormally attacking the lining of the large intestine (colon), causing inflammation and ulcers, as supported by recent studies 1.

Key Factors Contributing to Ulcerative Colitis

  • Genetic factors play a significant role, with approximately 10-25% of patients having a family history of inflammatory bowel disease.
  • Environmental triggers may include certain medications (like NSAIDs), diet, stress, and intestinal infections.
  • The gut microbiome (bacteria in the digestive tract) also appears to influence disease development and progression.
  • Western diets high in processed foods, refined sugars, and low in fiber may contribute to risk.

Pathogenesis and Treatment

The pathogenesis of IBD, including ulcerative colitis, is thought to involve the migration of lymphocytes from lymphoid tissues to the intestines, where they promote inflammation, as discussed in 1. Treatment typically involves anti-inflammatory medications, immunosuppressants, biologics, and in severe cases, surgery, with recent advancements including the use of small molecule therapies like JAK inhibitors, as noted in 1.

Importance of Early Diagnosis and Treatment

While there's no way to prevent ulcerative colitis, early diagnosis and treatment can help manage symptoms and prevent complications, improving patient outcomes and quality of life, as emphasized in 1.

From the Research

Causes of Ulcerative Colitis (UC)

The exact cause of Ulcerative Colitis (UC) is still not fully understood, but several factors have been identified as contributing to the development of the disease. These include:

  • Genetic factors: studies have shown that genetic susceptibility plays a role in the development of UC 2, 3
  • Environmental factors: a Western diet and lifestyle factors that influence the host's microbiome or immune response to antigens have been associated with an increased risk of UC 4
  • Microbial factors: an imbalance of the gut microbiome, also known as dysbiosis, has been implicated in the pathogenesis of UC 2, 5
  • Immune system dysfunction: UC is characterized by a chronic immune-mediated inflammatory response, which is driven by the interaction of genetic, environmental, and microbial factors 2, 6

Key Factors Contributing to UC

Some of the key factors that contribute to the development of UC include:

  • Diet: a Western diet has been associated with an increased risk of UC 4
  • Medications: certain medications may trigger or exacerbate UC symptoms 4
  • Lifestyle factors: lifestyle factors that influence the host's microbiome or immune response to antigens may contribute to the development of UC 4
  • Genetic predisposition: certain genetic mutations may increase the risk of developing UC 2, 3

Current Understanding of UC

Despite the identification of these contributing factors, the exact cause of UC remains unclear. Research is ongoing to clarify the underlying mechanisms of the disease and to identify potential therapeutic targets 4, 2, 6, 5, 3

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Uncovering the cause of ulcerative colitis.

JGH open : an open access journal of gastroenterology and hepatology, 2019

Research

Epidemiology and Pathogenesis of Ulcerative Colitis.

Gastroenterology clinics of North America, 2020

Research

Acute severe ulcerative colitis: latest evidence and therapeutic implications.

Therapeutic advances in chronic disease, 2018

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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