There are 5 subtypes of crohn's because it can affect any part of the GI tract from mouth to anus...the inflammation for CD is patchy regardless where it's affecting and it can go through the many layers of the intestinal lining unlike UC which is limited to the rectum/colon, is not patchy inflammation and stays on the surface of the lining only.
The 5 Types of Crohn's Disease and Their Symptoms:
•Ileocolitis: Someone with this subtype can have diarrhea and substantial loss of weight. It is also associated with cramping or pain in the middle or lower right areas of the abdomen.
•Ileitis: This kind of Crohn's also causes diarrhea, weight loss and cramping or pain, but fistulas and abscesses are also possible in the lower abdomen.
•Gastroduodenal Crohn's disease: This type of Crohn’s can cause lack of appetite, nausea, and loss of weight. There is also the chance of obstructions, which can cause vomiting.
•Jejunoileitis: There is also the chance of fistulas with this type of Crohn's. It can cause pain in the abdomen that can range from light to heavy. One can experience cramps after eating, and suffer from diarrhea.
•Crohn's (granulomatous) colitis: Fistulas, milder (comparatively) ulcers and abscesses near the anus. Diarrhea is present. A person with granulomatous can also have rectal bleeding , pain in the joints and skin lesions.
Here's the full link..
http://www.healthline.com/health/crohns-disease/types
CD can also cause constipation issues while in an active flare as well for some of us.