Crohn's disease is a complex illness that seems to be caused, at least in part, by an over-active immune system that attacks some of the body's own tissues. The symptoms can come and go, and they can vary from patient to patient — which may be one reason why some patients go undiagnosed for years. But make no mistake about it: if you have any of the symptoms below, you should see a gastroenterologist and get tested for Crohn's disease.

Bouts of Diarrhea

Sometimes it takes patients a while to realize that their bouts of diarrhea are related and that they are not just individual events. If you have two or three bouts of diarrhea spaced a few weeks apart, then it could possibly be a coincidence, as if you had food poisoning repeatedly. Anything more than that, though, and you should get tested for Crohn's disease. It's typical for patients to have diarrhea for a few days, and then it goes away, and then it comes back again for a few more days. Sometimes, though, the bouts of diarrhea last weeks, not days.

Abdominal Cramping

This is one of the hallmark symptoms of Crohn's disease. You may feel cramps come up out of nowhere, and they may last for a few minutes or a few hours. The cramping often occurs at the same time as diarrhea, but not always. Some patients have cramps but no diarrhea. Others have cramps followed by diarrhea. The cramps may be isolated to one area of your abdomen, or they radiate all through the abdomen.

Fever and Fatigue

Most people with Crohn's disease have periodic bouts of fever, and they have times when they feel worn down. The fever is due to the activity of your overactive immune system. The fatigue has the same cause, but it's also made worse by the fact that you're not able to absorb enough nutrition from your food when your Crohn's disease is acting up. It's often the fever and fatigue accompanying digestive ailments that cues gastroenterologists into the idea that Crohn's is a possibility.

Blood in the Stool

When your immune system is attacking your intestinal lining, it causes the intestinal lining to bleed. This can result in the appearance of blood in your stool. Usually, this blood is bright red. There may be a little, or there may be a lot.

If you experience any of the issues above, contact a gastroenterologist and ask about being tested for Crohn's disease. If you do have it, early treatment is best.