Systemic Lupus Erythematosus (SLE), or lupus, is a chronic autoimmune disease that can cause inflammation and damage to multiple organs, including the skin, joints, and kidneys. Inflammatory Bowel Disease (IBD) refers to Crohn’s disease and ulcerative colitis, characterized by chronic inflammation of the gastrointestinal (GI) tract. While they are recognized as separate conditions, it is possible for an individual to have both lupus and IBD, a co-occurrence that stems from shared underlying mechanisms.
The Shared Autoimmune Connection
The development of more than one autoimmune condition in the same person is known as polyautoimmunity. Both lupus and IBD arise from a dysregulated immune response where the body fails to distinguish between foreign invaders and its own healthy tissues, leading to self-attack. This shared origin helps explain why a person with a genetic predisposition for one autoimmune disease may be susceptible to another.
Specific genetic markers and human leukocyte antigen (HLA) types show a correlation with both diseases, suggesting a hereditary link that makes certain individuals more vulnerable. Environmental factors are also believed to play a part in triggering these conditions in genetically susceptible people. These triggers can activate similar inflammatory pathways and immune cells in both disorders.
Recent research also points to the gut microbiome as a significant factor. Studies have identified overlapping microbial signatures in patients with lupus and IBD that are distinct from those in other autoimmune diseases. These shared gut bacteria profiles may influence common inflammatory responses, further connecting the two conditions on a molecular level.
Distinguishing Symptoms and Clinical Features
Although lupus and IBD have common roots, their symptoms help distinguish them, though some general symptoms can overlap and create initial confusion. Individuals with either condition may experience fatigue, fever, and joint pain. Abdominal pain can also be a feature of both, although it is far more central to IBD.
Lupus has wide-ranging effects on the body. One of the most recognized signs is a malar rash, a butterfly-shaped rash across the cheeks and nose. Photosensitivity, where skin reacts abnormally to sunlight, is also common. Beyond the skin, lupus can affect the kidneys, leading to a serious complication called lupus nephritis, as well as the heart, lungs, and central nervous system.
In contrast, IBD symptoms are primarily concentrated in the gastrointestinal tract. Persistent diarrhea, urgent bowel movements, abdominal cramping, rectal bleeding, and unintended weight loss are hallmark signs of IBD. There are distinctions within IBD as well; Crohn’s disease can affect any part of the GI tract from the mouth to the anus, while ulcerative colitis is limited to the large intestine.
The Diagnostic Process
Diagnosing a patient who may have both lupus and IBD requires a comprehensive evaluation that goes beyond a single test. The process begins with a thorough review of the patient’s medical history and a physical examination to identify characteristic signs of each disease.
Blood tests look for specific autoantibodies for lupus, such as antinuclear antibodies (ANA) and anti-double-stranded DNA (anti-dsDNA) antibodies. While these are markers for lupus, some can also appear in IBD patients, especially those on certain medications. For IBD, blood tests may show markers of inflammation like C-reactive protein (CRP), and a stool test for fecal calprotectin can indicate intestinal inflammation.
To confirm an IBD diagnosis, direct visualization of the gastrointestinal tract is necessary. An endoscopy or colonoscopy allows a physician to view the lining of the digestive tract and take small tissue samples, or biopsies. Examining these biopsies provides definitive evidence of inflammation characteristic of either Crohn’s disease or ulcerative colitis. Imaging studies can also help assess the extent and location of inflammation.
Co-Managing Lupus and IBD
Managing a patient with both lupus and IBD involves a collaborative approach between specialists, a rheumatologist for lupus and a gastroenterologist for IBD. The goal is to create a treatment plan that addresses the inflammation driving both conditions without worsening either one. This requires careful coordination and monitoring.
Several medications are effective for both diseases. Corticosteroids are often used to control acute flare-ups of inflammation in both lupus and IBD. For long-term management, immunosuppressants such as azathioprine or methotrexate can help regulate the overactive immune system in both conditions.
A challenge in co-management is the risk of drug-induced lupus. Certain biologic medications used to treat IBD, such as anti-TNF agents like infliximab and adalimumab, can trigger lupus-like symptoms in some patients. This is not true lupus but a reaction that resolves after stopping the medication. Doctors must monitor patients on these therapies for new symptoms like rashes or joint pain and may need to adjust treatment if a drug-induced reaction is suspected.