WHEN YOU THINK of ulcerative colitis (UC), you likely conjure up the Big Three symptoms: cramping, bloating, and diarrhea (and a world of related pain). But while those signals are often the tipping point that sends people to their doctor’s offices for an official UC diagnosis, there are many other less-known—and often surprising!—symptoms of this chronic condition that don’t have anything to do with going to the loo. Understanding what they are can give you a head start on getting help when something isn’t feeling right.

But First, a Gut Check

While UC does have non-GI-related symptoms, the gut is usually what speaks up first when it comes to any inflammatory bowel condition. “It’s rare for GI symptoms to come later,” says Niket Sonpal, M.D., a gastroenterologist and assistant medical professor at Touro College in New York City. Because bathroom-related symptoms can be mistaken for other conditions though, if you have GI distress plus these non-GI symptoms, it could help your doctor make a diagnosis of inflammatory bowel disease versus irritable bowel syndrome, which will dictate your treatment plan.

You’re Losing Weight

Losing a pound or three is typically a cause for celebration not concern, but if your scale’s needle is moving too much—and too rapidly—it could be a sign of UC, which can lead to a malabsorption of nutrients. One study found that 51% of those with UC had lost a significant amount of weight (more than 5% BMI loss) prior to their diagnosis. If you’ve lost more than 5% of your body weight in less than six months—and you know it’s not because of that new Daily Burn sweat session you started—see your doctor.

You’ve Lost Your Mojo

That slow-mo feeling can have so many causes that it’s easy to blame a lack of get-up-and-go on anything but the gut. Turns out, though, that having UC can prevent vitamin B-12 from being absorbed in your body, which can be the culprit for low-energy days, says Sunitha D. Posina, M.D., an internal medicine specialist in Stony Brook, NY. If you’re running really low on vitamin B, your gastro may prescribe an injection or nasal spray to help you get back on track.

Your Joints Ache

According to the Crohn’s and Colitis Foundation, arthritis is the most common non-GI symptom of UC and can affect as many as 30% of those with the disease. Blame it on the inflammatory nature of this chronic condition—because UC is a type of inflammatory bowel disease (IBD), it makes you susceptible to all types of inflammation, including in the joints. Good news, though: Once your underlying intestinal inflammation is under control, your arthritis is not likely to be as severe as it would be if the root cause was the joint itself.

Your Skin Is Erupting

A gut issue may be the last thing you think of when you have a skin rash, but it’s the next most common non-GI symptom after arthritis. Those with UC are more prone to a condition known pyoderma gangrenosum, a fancy term for coin-sized, painful lesions found on the shins. “A lot of times, people dismiss it and just think they hit their leg or something at first, or think it’s just a rash, but these types of skin conditions can be a sign that the bowels are out of control,” says Dr. Sonpal. Antibiotics, injections, and ointments are common treatments.

You’re Feeling Down

Malnutrition from vitamin D can be also an issue with UC, particularly if the small intestine is involved, because that’s where calcium is absorbed, says Dr. Posina. Known as the sunshine vitamin because of its studied mood-boosting benefits, a deficiency of vitamin D can be an unexpected reason for the blues. The Crohn’s and Colitis Foundation recommends a vitamin D supplement of 800 IU per day.

Your Eyesight Is Slipping

Visual issues are another unexpected UC symptom, says Dr. Sonpal. About 10% of UC patients also have some type of eye condition such as light sensitivity, vision problems, or discomfort. One of the most common is an eye inflammatory condition called iritis, which causes redness and pain. In mild cases, any visual changes will clear up once the underlying UC is taken care of, but if the condition has become more severe, your gastro may loop in an eye doc for a partnered treatment plan.

You Feel Weak

Another common non-GI UC symptom is anemia, or a lack of iron, which can cause fatigue and dizziness. “Patients with UC are more prone to bleeding, so they could become iron-deficient, which is why I recommend monitoring iron levels,” says Gabriela Garnder, R.D., a clinical dietitian with Memorial Hermann-Texas Medical Center’s Ertan Digestive Disease Center in Houston. According to the Crohn’s and Colitis Foundation, long-term irritation and swelling in your intestines can also interfere with your body’s ability to use and absorb iron properly.

When in Doubt, Check It Out

The tricky thing about UC is how it can create secondary issues quickly if left untreated, and that can make it tough to tell what’s causing what. That’s why knowing all the symptoms of UC is key. “You may not think anything is wrong at first if you have bloating or diarrhea—you may think maybe you’re just not eating enough fiber,” says Dr. Sonpal. “But if you develop more severe symptoms like joint aches, weight loss, and visual issues, it’s an additional cue that you may have UC and should see a doctor.”