Proctitis is an inflammation of the lining of the rectum and anus. It is usually caused by underlying medical conditions such as sexually transmitted infections (STIs), autoimmune diseases (such as Crohn’s disease or ulcerative colitis), inflammatory bowel disease (IBD), anal trauma, strep throat in children and infections that are not sexually transmitted, such as salmonella and shigella rectal Clostridium difficile infections that occur after antibiotic use radiation treatments for ovarian, rectal, or prostate cancer.http://blog.drsundardas.com/inflammatory-bowel-disease/