Your pathology report for chronic active enteritis

by Jason Wasserman MD PhD FRCPC
June 13, 2025

Chronic active enteritis refers to ongoing (chronic) inflammation in the small intestine, accompanied by recent (active) inflammation. Pathologists use this term after examining a tissue sample under a microscope. They observe a mixture of immune cells that indicates inflammation has been present for an extended period and is currently active. They may also see specific types of tissue damage resulting from long-term irritation and recent injury.

What are the symptoms of chronic active enteritis?

Since chronic active enteritis involves both ongoing and recent inflammation, symptoms can vary and may include:

  • Persistent diarrhea, sometimes lasting weeks or months.

  • Abdominal pain or cramping, which might worsen during flare-ups.

  • Bloating and excess gas.

  • Reduced appetite, weight loss, or trouble absorbing nutrients.

  • Fatigue and weakness, often due to nutritional deficiencies.

  • Fever or sudden worsening of symptoms during active episodes.

Symptoms can fluctuate, worsening during periods of active inflammation and improving during calmer periods.

What causes chronic active enteritis?

Several conditions may cause chronic active enteritis, including:

  • Inflammatory bowel disease (IBD): Conditions such as Crohn’s disease or ulcerative colitis typically involve ongoing inflammation with episodes of more severe (active) inflammation.

  • Celiac disease: An autoimmune condition triggered by gluten, leading to continuous inflammation and periodic active flare-ups.

  • Medication effects: Regular use of medications like non-steroidal anti-inflammatory drugs (NSAIDs) or certain antibiotics can cause persistent and occasionally active intestinal inflammation.

  • Chronic infections: Long-lasting infections caused by bacteria or parasites can lead to ongoing inflammation, with periodic active flare-ups.

  • Radiation therapy: Previous radiation treatment to the abdomen or pelvis can cause lasting inflammation with active episodes.

Your doctor will evaluate your medical history, symptoms, and other test results to identify the underlying cause.

Chronic changes

The word “chronic” indicates that inflammation has been present for an extended period—weeks, months, or even years. Under the microscope, pathologists observe immune cells known as lymphocytes and plasma cells. These cells suggest the immune system has continually responded to ongoing irritation or injury.

Chronic inflammation often results in specific types of tissue damage, such as:

  • Villous atrophy and blunting: Damage or flattening of tiny finger-like structures (villi) that line the intestine, affecting nutrient absorption.

  • Granulomas: Small, organized clusters of immune cells forming in response to chronic inflammation.

Symptoms related to chronic changes often include persistent diarrhea, reduced nutrient absorption, and gradual weight loss or fatigue.

Active changes

The term “active” indicates recent or sudden inflammation. Pathologists identify active inflammation by seeing immune cells called neutrophils. Neutrophils appear when there is immediate irritation, infection, or injury to the intestine.

Active inflammation can also cause specific types of tissue damage, such as:

  • Ulceration: Open sores on the surface of the intestine caused by recent tissue injury.

  • Cryptitis: Inflammation affecting the crypts, small glands located in the intestinal lining.

  • Crypt abscesses: Collections of neutrophils and debris within the intestinal crypts, indicating active inflammation.

Symptoms associated with active inflammation typically include increased abdominal pain, sudden diarrhea, fever, or a sudden worsening of existing symptoms.

Why is identifying chronic active enteritis important?

Recognizing chronic active enteritis is important because it helps your doctor understand both the ongoing and recent inflammation affecting your intestine. Knowing this helps guide your doctor toward the correct diagnosis and appropriate treatment. Early recognition and proper management can alleviate symptoms, prevent further damage to your intestine, and enhance your overall quality of life.

Questions to ask your doctor

  • What specific condition might be causing my chronic active enteritis?

  • Do I need additional tests to confirm the underlying cause?

  • What treatments do you recommend based on this diagnosis?

  • How soon can I expect to feel better after starting treatment?

  • Are there dietary or lifestyle changes that could help manage or reduce my symptoms?

  • Will I require ongoing follow-up or monitoring?

  • Should my family members be tested for related conditions?

  • What symptoms should prompt me to seek immediate medical care?

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