肛门直肠脓肿十分常见,普通人群中患病率约0.18%。[11]Gilliland R, Wexner SD. Complicated anorectal sepsis. Surg Clin North Am. 1997;77:115-153.http://www.ncbi.nlm.nih.gov/pubmed/9092106?tool=bestpractice.com克罗恩病患者中肛门直肠脓肿的发生率近1/3,其中男性的患者数是女性的2-3倍,而绝大多数脓肿发生于20-40岁克罗恩病患者中,春、夏季发病率高。[12]Kovalcik PJ, Peniston RL, Cross GH. Anorectal abscess. Surg Gynecol Obstet. 1979;149:884-886.http://www.ncbi.nlm.nih.gov/pubmed/505265?tool=bestpractice.com[13]Read DR, Abcarian H. A prospective survey of 474 patients with anorectal abscess. Dis Colon Rectum. 1979;22:566-568.http://www.ncbi.nlm.nih.gov/pubmed/527452?tool=bestpractice.com