Aetiology and assessment of infective proctitis

Infective proctitis caused by a sexually transmissible infection (STI) usually occurs within a few days to weeks following receptive anal sex. Patients may present with anal pain, discharge, discomfort, bleeding, altered bowel habit (constipation is predominant but diarrhoea can also occur) or tenesmus.

For patients presenting with diarrhoea, infective proctitis can be difficult to differentiate from infectious diarrhoea or noninfective causes such as inflammatory bowel disease. Discharge may be difficult to distinguish from diarrhoea, particularly in cases of proctitis caused by lymphogranuloma venereum (LGV). If diarrhoea is present, consider faecal testing in addition to other investigations.

Sexually transmissible pathogens commonly involved in infective proctitis are Neisseria gonorrhoeae, Chlamydia trachomatis (including the LGV serovar, which causes severe inflammation), Treponema pallidum (syphilis), monkeypox virus and herpes simplex virus (HSV). Mycoplasma genitalium is commonly identified in anorectal swabs from gay, bisexual and other men who have sex with men, and transgender women but its pathogenicity is uncertainBissessor, 2016Workowski, 2021.

For cases of suspected proctitis, take anorectal swabs forOng, 2023:

  • nucleic acid amplification testing (NAAT) (eg polymerase chain reaction [PCR]) for N. gonorrhoeae, C. trachomatis with LGV typing, HSV, T. pallidum and mpox
  • culture and susceptibility testing for N. gonorrhoeae.

Perform serological testing for syphilis and HIV in gay, bisexual and other men who have sex with men, and transgender women presenting with proctitis.

In cases of painful proctitis, lubrication of anorectal swabs with sterile water or saline may reduce pain associated with swabbing. Proctoscopy may help to identify ulcers or noninfective causes of anal symptoms, but it can be painful and is usually unnecessaryde Vries, 2014.

For general principles of STI management, including investigations and counselling, and considerations for children in whom an STI is identified, see Principles of STI management.