Comorbidities
When people think about ulcerative colitis, they picture bowel symptoms: urgency, bloody diarrhea, cramping. What they often do not expect is waking up with swollen knees, developing painful red lumps on their shins, or sitting in an ophthalmologist's office with blurred vision. These are extraintestinal manifestations (EIMs), and they affect a significant number of people with UC. According to the Crohn's and Colitis Foundation, up to 50% of people with inflammatory bowel disease develop symptoms outside of the intestines at some point during their disease course. A 2025 study published in Egyptian Rheumatology and Rehabilitation confirmed a clear correlation between the severity of intestinal disease activity and the likelihood of extraintestinal involvement. Understanding which symptoms track with flares and which can appear independently is essential for catching complications early and getting the right treatment.
Ulcerative Colitis Joint Pain: The Most Common Surprise
Joint pain is the single most frequent extraintestinal manifestation of ulcerative colitis, affecting up to 40% of people with IBD. The joint involvement falls into two distinct categories, and knowing the difference matters for treatment.
Peripheral arthropathy targets larger joints like the knees, ankles, wrists, and elbows. This form tends to mirror gut inflammation closely. When your colon flares, your joints flare. When intestinal disease is brought under control, the joint symptoms typically resolve as well. The Crohn's and Colitis Foundation notes that peripheral arthritis in IBD is generally non-erosive, meaning it usually does not cause permanent joint damage.
Axial arthropathy, which includes sacroiliitis and ankylosing spondylitis, behaves differently. It affects the spine and sacroiliac joints, causing lower back pain and stiffness that is typically worse in the morning and improves with movement. Unlike peripheral arthritis, axial disease does not necessarily correlate with intestinal flares and may require separate treatment with biologics, since standard UC medications like aminosalicylates and corticosteroids often do not address spinal inflammation. About 3% of people with IBD develop full ankylosing spondylitis, but milder sacroiliitis is considerably more common.
Skin Problems That Signal Deeper Inflammation
Ulcerative colitis skin problems affect roughly 15% to 20% of people with IBD, and the two most clinically significant conditions are erythema nodosum and pyoderma gangrenosum.
Erythema nodosum produces tender, raised, reddish-purple nodules, most commonly on the front of the shins. It nearly always tracks with disease activity. In a study of patients with chronic ulcerative colitis, the disease was active in 90% of patients who developed erythema nodosum. These nodules typically resolve when the underlying colitis is treated and do not leave scarring.
Pyoderma gangrenosum is rarer but more serious. It begins as small pustules or blisters, often on the legs, that rapidly break down into deep, painful ulcers with undermined, violaceous borders. Unlike erythema nodosum, pyoderma gangrenosum does not always follow flare activity and can develop even during remission. Treatment may require systemic immunosuppressants or biologics, and a critical clinical point is that surgical debridement should be avoided, as cutting into pyoderma gangrenosum lesions can trigger pathergy, a phenomenon where the wound worsens in response to trauma.
Eye Issues That Require Prompt Attention
Ocular manifestations occur in 4% to 12% of people with IBD and range from mildly uncomfortable to vision-threatening.
Episcleritis, the most common ocular manifestation, causes redness, mild pain, and watering in one or both eyes. It tends to correlate with intestinal disease activity and usually resolves when colitis is controlled. While uncomfortable, episcleritis does not typically threaten vision.
Uveitis is a different situation entirely. This condition involves inflammation of the uvea, the middle layer of the eye, and causes blurred vision, eye pain, light sensitivity, and redness. Uveitis does not necessarily follow UC flare patterns and can occur during periods of intestinal remission. Without treatment, uveitis can lead to permanent vision loss, glaucoma, and cataracts. Any sudden change in vision, new eye pain, or persistent redness warrants an urgent evaluation by an ophthalmologist, not just an optometrist.
Mouth Ulcers, Hair Loss, and Other Manifestations
Ulcerative colitis mouth ulcers, specifically aphthous stomatitis, appear in at least 10% of UC patients. These painful sores develop on the inner cheeks, gums, and tongue and tend to worsen during flares. A less common but more specific oral manifestation called pyostomatitis vegetans, which produces small pustules on the gums and inner cheeks, is considered a specific marker of UC and should prompt gastroenterological evaluation if a diagnosis has not yet been established.
Ulcerative colitis hair loss is frequently reported, with a cross-sectional study finding that 33% of IBD patients experienced hair thinning. The causes are multifactorial. Telogen effluvium, where hair shifts prematurely into a shedding phase, can result from active inflammation, nutritional deficiencies (particularly iron and zinc), or the physiological stress of flares. Some UC medications, including azathioprine and methotrexate, can also contribute. Separately, alopecia areata, an autoimmune form of hair loss, shares genetic pathways with inflammatory bowel disease and may occur as a co-existing condition rather than a direct consequence of colitis.
Why Tracking Non-GI Symptoms Matters
The updated 2025 ACG guidelines now explicitly recommend that treatment decisions for moderately to severely active UC should factor in the presence of extraintestinal manifestations. A biologic that controls both your colitis and your joint disease, for example, may be a better choice than one that addresses the gut alone. But your gastroenterologist can only factor in what they know about.
Many EIMs are dismissed by patients as unrelated problems. Joint pain gets attributed to aging. Skin changes are treated by a dermatologist who may not connect them to IBD. Eye symptoms lead to an optometrist visit that misses the inflammatory cause. Bringing all of these threads together gives your GI team a complete picture.
Log your joint pain, skin changes, and other non-GI symptoms in Aidy alongside your bowel symptoms. Seeing correlations between extraintestinal symptoms and flares helps your GI team make better treatment decisions.