Ulcerative colitis can easily be mistaken for IBS because the two conditions share several digestive symptoms.
But certain warning signs, including changes that extend beyond the gut, can help reveal an important difference.
One clue separates them. IBS causes discomfort but does not damage the digestive tract or cause bleeding, while ulcerative colitis (UC) inflames the lining of the colon and rectum.
Blood in the stool is one of its hallmark signs. UC is also not rare. The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) estimates that 600,000 to 900,000 Americans are living with it, and diagnosis often lands between ages 15 and 30.
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Left uncontrolled, UC also raises the risk of colorectal cancer.
The 8 warning signs to watch
1. Blood in the stool. This is the sign that most reliably separates UC from IBS. NIDDK lists "passing blood with your stool or rectal bleeding" among the core symptoms.
2. Frequent, watery diarrhea. Mild cases involve fewer than four bowel movements a day. Severe cases, which NIDDK calls fulminant, can exceed 10 bloody bowel movements a day.
3. Sudden, urgent trips to the bathroom. NIDDK describes "an urgent need to have a bowel movement" that leaves little warning, a classic UC symptom that often disrupts work and sleep.
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4. Tenesmus. NIDDK describes it as "feeling a constant urge to have a bowel movement even though your bowel may be empty." IBS can cause a sense of incomplete evacuation, but UC's version comes with pain and blood.
5. Lower-abdominal cramping. "Cramping and pain in the abdomen" is a core UC symptom, according to NIDDK, and typically sits low in the belly rather than spreading across it.
6. Mucus or pus in the stool. Ulcerated tissue in the colon can shed mucus or pus alongside blood, something IBS does not produce.
7. Fatigue, fever and unintended weight loss. In more advanced disease, chronic inflammation and blood loss drain energy and appetite. NIDDK lists fatigue, fever, nausea and weight loss among symptoms of more severe UC.
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8. Signs outside the gut. According to Cleveland Clinic, about 25 percent of UC patients also develop symptoms beyond the intestine, including "Joint pain and swelling," "Red, burning or itchy eyes," and "Painful bumps, rashes or ulcers on your skin."
Why the clues outside the gut matter
UC is a whole-body inflammatory disease, not just a gut problem. NIDDK notes that some patients develop inflammation in "the joints, causing certain types of arthritis; the skin; the eyes; liver and bile ducts."
These clues often appear during a flare and can be the first thing that pushes a patient, or a clinician, to look past an IBS label.
When to see a doctor
Anyone with persistent diarrhea, visible blood in the stool or unexplained weight loss should see a healthcare provider.
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Diagnosis usually involves a colonoscopy, which can also screen for the colorectal cancer risk that UC carries over time.
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This article is made and published by Mie Hermansen, who may have used AI in the preparation.