Systemic Lupus Erythematosus (SLE) is a chronic autoimmune condition where the immune system mistakenly attacks the body’s healthy tissues and organs. This widespread attack can affect nearly any part of the body, including the digestive tract. Lupus can cause diarrhea, but the cause is often complex, arising from either the disease’s activity or as a side effect of necessary treatments. Gastrointestinal issues are common in people with SLE; over 50% experience symptoms like abdominal pain, nausea, or changes in bowel habits. Understanding the root cause of the diarrhea is important for managing this disruptive symptom.
How Lupus Activity Directly Causes Diarrhea
Diarrhea resulting directly from active Lupus is typically caused by inflammation or damage to digestive system tissues. The most specific cause is Lupus Enteritis, which occurs when the immune system targets the blood vessels supplying the small intestine (mesenteric vasculitis). This attack leads to swelling and thickening of the intestinal wall, disrupting its normal function of absorbing water and nutrients. The resulting inflammation and decreased blood flow can irritate the intestine, leading to watery stool and diarrhea. The diarrhea associated with this condition often occurs alongside acute abdominal pain. Lupus Enteritis is an uncommon manifestation of SLE, but it signals a severe flare requiring immediate medical attention.
Medications and Other Related Causes of Diarrhea
Diarrhea is frequently a side effect of the medications used to control Lupus, rather than a symptom of the disease flare itself. Many anti-inflammatory and immunosuppressive drugs required to manage SLE can irritate the gastrointestinal tract lining. For instance, nonsteroidal anti-inflammatory drugs (NSAIDs), commonly used for joint pain, can cause stomach irritation, ulcers, and diarrhea.
Immunosuppressants such as Mycophenolate Mofetil and Methotrexate are known to cause gastrointestinal upset, including diarrhea, as a common side effect. Even corticosteroids like Prednisone can sometimes cause gastrointestinal irritation.
Furthermore, people with Lupus may have co-occurring conditions, such as Irritable Bowel Syndrome (IBS), which presents with symptoms like gas, abdominal pain, and alternating diarrhea or constipation.
Associated Gastrointestinal Issues in Lupus Patients
Lupus involvement often extends beyond diarrhea, presenting a range of other symptoms affecting the entire digestive tract. Abdominal pain is the most common complaint, frequently accompanying diarrhea during a Lupus Enteritis flare.
This pain can be diffuse and severe, resulting from inflammation of the abdominal lining (peritonitis) or from vasculitis affecting the gut. Nausea and vomiting are also frequent symptoms, caused by inflammation or medication side effects.
Inflammation of the esophagus can lead to difficulty swallowing or acid reflux (Gastroesophageal Reflux Disease, or GERD). Open sores in the mouth, known as mouth ulcers, are a common manifestation of Lupus activity.
Severe intestinal inflammation can prevent the small intestine from properly absorbing nutrients, potentially leading to malabsorption and unintended weight loss.
When Diarrhea Requires Medical Attention
While many episodes of diarrhea can be managed at home, certain symptoms warrant immediate contact with a healthcare provider, especially for individuals with Lupus.
Warning Signs
- Diarrhea accompanied by blood in the stool (bright red or dark and tarry), which may indicate bleeding from ulcers or severe inflammation.
- Severe, acute abdominal pain that is sudden and intense, signaling a serious complication like mesenteric vasculitis or pancreatitis.
- Signs of dehydration, such as excessive thirst, reduced urination, or dizziness, which develop quickly with persistent diarrhea.
- A high fever accompanying the diarrhea, suggesting a severe active flare or a secondary infection.
Tracking the timing of symptoms relative to changes in medication or diet can assist the medical team in determining the underlying cause.