STI-associated syndromes guide: Proctitis

On this page:

• Public health importance
• Common STI-associated etiology
• Clinical manifestations
• Diagnostic testing
• Empiric treatment and management
• Follow-up
• Reporting and partner notification
• References

Public health importance

Infections of the anus and rectum can be sexually transmitted by digital-anal and oral-anal contact, receptive anal sex and, in females, through trans-mucosal spread of genital fluid^{Footnote 1}.

Proctitis caused by sexually transmitted infections (STI), including sexually transmitted enteric infections (STEI), disproportionately impact gay, bisexual and other men who have sex with men (gbMSM). Rectal STI and STEI may increase the risk for HIV acquisition^{Footnote 2}.

Since the 1970s, increased transmission and outbreaks of Shigella sonnei and Shigella flexneri have been documented among sexual networks of gbMSM, and antibiotic-resistant Shigella was included in the World Health Organization's 2017 list of antibiotic-resistant "priority pathogens" that pose significant public health threats^{Footnote 3Footnote 4Footnote 5Footnote 6Footnote 7}.

Common STI-associated etiology

Proctitis can be caused by infectious agents. STI associated with proctitis include: Chlamydia trachomatis (CT) [lymphogranuloma venereum (LGV) and non-LGV genotypes], Neisseria gonorrhoeae (GC), Treponema pallidum (T. pallidum), Herpes simplex virus type 1 or 2 (HSV-1 or HSV-2), and mpox virus^{Footnote 8Footnote 9Footnote 10}.

In one study of gay, bisexual and other men who have sex with men (gbMSM) with proctitis, the following etiological agents were identified^{Footnote 11}:

• GC (20%)
• HSV-1 and HSV-2 (13%)
• CT (11%)
• Mixed infections (10%, including 3% with HSV-1 and HSV-2)
• T. pallidum (syphilis) (1%)

Rates of infectious syphilis have increased in Canada in recent years and outbreaks have been declared in most provinces and territories since 2017. Consider syphilis in people presenting with proctitis.

Infection with LGV genotypes of C. trachomatis can present with anorectal symptoms^{Footnote 12Footnote 13Footnote 14Footnote 15}.

Mpox should also be considered as a possible cause of proctitis^{Footnote 9Footnote 10}. From April 28, 2022 until September 29, 2023, 1,515 cases of mpox were reported in Canada, disproportionately impacting gay, bisexual and other men who have sex with men^{Footnote 16Footnote 17Footnote 18}.

Enteric infections can also be acquired through oral-anal and, in some cases, digital-anal sexual activities and result in proctocolitis and enteritis^{Footnote 8Footnote 19}. Proctocolitis may be associated with Entamoeba histolytica, Campylobacter species , Salmonella species and Shigella species^{Footnote 1Footnote 8Footnote 19}. Enteritis may be associated with Giardia lamblia infection^{Footnote 8Footnote 19}. Outbreaks of extensively drug resistant Shigella species (XDR Shigella) and other enteric infections have occurred among sexual networks of gbMSM in high-income countries in recent years^{Footnote 1Footnote 2Footnote 3Footnote 4Footnote 8Footnote 19}. Consult an experienced colleague for the treatment and management of proctocolitis and enteritis as these are beyond the scope of this guide.

In persons with advanced human immunodeficiency virus (HIV) infection, consider cryptosporidium, microsporidium, cytomegalovirus, and other opportunistic infectious agents in the differential diagnosis^{Footnote 1Footnote 8}.

Clinical manifestations

Symptoms and signs of proctitis include:

• Anorectal pain
• Anorectal ulcers
• Continual or recurrent inclination to evacuate the bowels
• Constipation
• Bloody stool
• Mucopurulent rectal discharge

Consider anoscopy for assessment of symptomatic individuals. Suspect LGV if inguinal or femoral lymphadenopathy is present. Bloody, purulent or mucous discharge from the anus as well as constipation are common with LGV^{Footnote 12Footnote 13Footnote 14Footnote 15}.

Mpox often presents with painful mucocutaneous lesions at the site of inoculation, most commonly the anogenital area^{Footnote 9Footnote 10Footnote 20}. When the anorectal mucosa is affected, individuals can experience anorectal pain, tenesmus, or diarrhea^{Footnote 9Footnote 10}.

Infection with enteric pathogens, including Campylobacter, Salmonella and Shigella species, can present with abdominal pain, diarrhea, cramping, bloating, nausea or fever^{Footnote 1Footnote 2Footnote 3Footnote 4Footnote 19}.

In people with HIV, there are additional potential causes of proctitis and infections are often more severe. Acute proctitis may present with bloody discharge, painful perianal ulcers or mucosal ulcers^{Footnote 1Footnote 19}.

Diagnostic testing

Investigations for cases of suspected infectious proctitis may include testing for chlamydia (including LGV), gonorrhea, syphilis, mpox and enteric infections. If ulcers are visualized, lesions can be sampled for LGV, HSV-1 and HSV-2, T. pallidum, and mpox virus. Refer to etiology-specific Sexually transmitted and blood-borne infections (STBBI) Guide(s) for information on diagnostic testing and interpretation of results.

Chlamydia (including LGV) and gonorrhea

• Obtain rectal swabs for nucleic acid amplification tests (NAAT) for CT and GC (where available), plus culture for GC (where available).
  • Request that CT-positive rectal specimens from people with symptoms compatible with LGV and from sexual partners of people diagnosed with LGV be forwarded to the provincial or territorial laboratory (if available) or the National Microbiology Laboratory (NML) for LGV genotyping.
• Obtain swabs from lesions or buboes for NAAT for CT and LGV.

Syphilis

• Where available, collect swabs of rectal lesions suspected as primary syphilis for NAAT or direct fluorescence for T. pallidum.
• Obtain syphilis serology.

HSV-1 and HSV-2

• Where available, obtain swabs from ulcerations or vesicles to test for HSV-1 and HSV-2 by NAAT or viral culture.

Mpox

• When mpox is suspected, lesion fluid and/or crust, scab, and skin swabs can be submitted for polymerase chain reaction (PCR) testing. Consult your provincial or territorial public health laboratory or the NML for instructions regarding specimen handling and transport before submitting specimens^{Footnote 18}. If mpox is suspected, use of airborne, droplet and contact precautions are recommended^{Footnote 18}.

Sexually transmitted enteric infections

• If clinical presentation or history indicates, collect stool specimen for culture for enteric pathogens and for examination for ova and parasites. Consult local laboratory for the availability of NAAT for protozoa.

Other tests

• Consider testing for Haemophilus ducreyi (chancroid) and Klebsiella granulomatis (granuloma inguinale) in people at risk of exposure.

Where other etiologies are suspected, the presentation is severe, or symptoms are persistent or recurrent, consider consulting an experienced colleague, a gastroenterologist or an infectious disease specialist for further investigation.

Empiric treatment and management

The decision to treat empirically for the common pathogens CT and GC or to wait for test results should reflect the:

• Severity of the clinical condition
• Probability of infection
• Person's risk factors for a sexually transmitted or blood-borne infection (STBBI)
• Person's willingness to abstain from sex and to return for test results or follow-up

When treating empirically, the presence of anorectal exudate is an indication to treat for both GC and CT^{Footnote 1Footnote 21}. For current treatment recommendations for GC, refer to the Gonorrhea Guide. For current treatment recommendations for CT, refer to the Chlamydia and LGV Guide.

Treat current sexual partners with the same empiric treatment regimen as the index case.

In people with risk factors for syphilis and a compatible presentations, consider empiric treatment if follow-up is uncertain. Refer to the Syphilis Guide for treatment recommendations, as appropriate.

Supportive care is a central part of mpox management as there is limited data on the clinical effectiveness of specific treatments for mpox infections in humans^{Footnote 16}. Consult an infectious disease physician to discuss therapeutic options for suspected or confirmed cases^{Footnote 16}.

Some existing treatments for smallpox, such as TPOXX (tecovirimat monohydrate capsules) may have a role to play in select instances^{Footnote 16}. TPOXX is an oral antiviral agent that is indicated for the treatment of human smallpox disease in adults and pediatric patients weighing at least 13 kg. It does not currently have an approved Health Canada indication for mpox or other Orthopoxviruses^{Footnote 16}. However, recommendations for its off-label use can be found at the following webpage: CADTH Health Technology Review on Tecovirimat (Tpoxx): Update.

Follow-up

Evaluate response to treatment in all individuals treated for proctitis. Where an etiology other than a sexually transmitted infection is suspected, the presentation is severe, or symptoms are persistent or recurrent, consider consulting an experienced colleague, a gastroenterologist or an infectious disease specialist for further investigation.

The need for test of cure (TOC) depends on which pathogen is confirmed by laboratory testing. Refer to the etiology-specific guide.

Suspected or confirmed cases of mpox should follow isolation recommendations as per your provincial, territorial, or local public health authority.

Reporting and partner notification

When treatment is indicated for an STI: notify, evaluate, test and treat (as appropriate) sexual partners. Refer to the etiology-specific guide(s) for guidance on reporting and partner notification.

For suspected or confirmed cases of mpox, refer to your provincial, territorial or local public health authority's reporting requirements and recommendations for contacts. For up-to-date guidance on pre-exposure and post-exposure vaccination for mpox, refer to the Canadian Immunization Guide or provincial and territorial vaccination schedules and guidelines.