Acute or chronic inflammation of the rectal mucosa



  • Predominant age: adults
  • Predominant sex: male > female
  • Ulcerative colitis (UC): 2 to 19 per 100,000 person-years
  • Gonococcal proctitis is most common in individuals <25 years of age.
  • People of Jewish descent are 3 to 5 times more likely to have UC.
  • Acute radiation proctitis; arises in almost all patients, self-limited, lasts up to 3 months after treatment


  • Prevalence of rectal chlamydia and rectal gonorrhea among men who have sex with men (MSM) is 9% and 5%, respectively.
  • In children diagnosed with UC:
    • 25% will only have ulcerative proctitis (UP).
    • Girls are twice as likely to have UP than boys.
  • >30% of patients with UC have isolated rectal involvement.
  • Proximal extension of UP increases from 20% at 5 years to 84% at 20 years.
  • Chronic radiation proctopathy (CRP):
    • Onset ranges from 8 to 13 months but can occur many years after radiation exposure.
    • Prevalence is 2–20%.
  • Diversion proctitis (DP): Onset is usually from 3 to 36 months after fecal diversion. <50% of patients are symptomatic.

Etiology and Pathophysiology

  • Chronic radiation proctitis secondary to ischemic and fibrotic changes
  • DP: Proximal fecal diversion causes increased nitrate-reducing bacteria and decreased obligate anaerobes resulting in short-chain fatty acids (SCFAs) deficiency.
  • Rectal intercourse in women or MSM can result in proctocolitis.
  • Infectious causes:
    • STIs:
      • Gonorrhea; chlamydia; syphilis
      • Herpes simplex virus (HSV; 90% HSV-2)
      • Lymphogranuloma venereum (LGV); chancroid
      • Cytomegalovirus (CMV)
      • Human papillomavirus (HPV)
    • Other:
      • Clostridium difficile
      • Enteric infections, including Campylobacter, Shigella, Escherichia coli, Salmonella, and amebiasis
  • Inflammatory causes:
    • UC
    • Crohn disease
  • Other causes:
    • Radiation injury
      • Occurs with doses 8 Gy or higher
      • Damage to intestinal cell DNA with helical breaks, inability to replicate and undergo normal cellular repair
      • Acute radiation injury usually occurs within 6 weeks of treatment.
    • Ischemia
    • Vasculitis
    • Toxins (e.g., hydrogen peroxide enemas)
    • Side effects of medications
Chronic radiation proctopathy” has replaced the term “radiation proctitis.”


  • Higher incidence of UC among certain ethnicities
  • In genetically predisposed individuals with dysregulated immune responses, GI infections may increase the risk of UP.

Risk Factors

  • STD-related proctitis: HIV-positive MSM with receptive anal intercourse
  • UP: protective factors: smoking and appendectomy
    • Risk factors: family history of inflammatory bowel disease (IBD), Jewish ancestry, NSAIDs, bisulfate, estrogen, gastroenteritis, GI dysbiosis, angiogenesis, lymphogenesis, impaired immune responses
  • CRP: pelvic radiation, chemotherapy, abdominal surgery, vascular disease, GI angioectasia, AV malformation, smoking, GI dysbiosis, patient comorbidities
  • DP; rectal injury; rectal medication use

General Prevention

Safe sex practices; condom use with anal intercourse

Commonly Associated Conditions

  • HIV
  • Malignancy in patients treated with pelvic radiotherapy

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