Proctitis and Proctocolitis Organism-Specific Therapy

Updated: Oct 06, 2021
  • Author: Leandro Feo, MD; Chief Editor: Thomas E Herchline, MD  more...
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Specific Organisms and Therapeutic Regimens

Organism-specific therapeutic regimens for proctitis and proctocolitis are provided below, including those for Neisseria gonorrhoeae, Chlamydiatrachomatis, Treponema pallidum, herpes simplex virus (HSV), Shigella, Salmonella, Entamoeba histolytica, and Clostridioides (Clostridium) difficile. [1, 2, 3, 4, 5, 6, 7, 8]

Empiric treatment should be directed at the etiology that is most likely on the basis of the history.

  • Travel to less developed country - Suspect enteric pathogen
  • Recent antibiotics - Suspect C difficile
  • Receptive anal intercourse - Suspect Neisseria, Chlamydia, syphilis, or Herpes

N gonorrhoeae

Regimens are as follows:

  • Ceftriaxone 500 mg IM as a single dose; for persons >150 kg, 1 g IM as a single dose [9] or
  • Gentamicin 240 mg IM as a single dose plus azithromycin 2 g PO as a single dose [9] or
  • Cefixime 800 mg PO as a single dose [9]
  • Concurrent treatment for chlamydial infection should also be given unless this infection has been excluded by microbiologic testing
  • Consider culture and infectious disease consultation if cephalosporin-resistant infection is suspected [9]

C trachomatis genotype A-K (non-lymphogranuloma venereum [LGV])

Regimens are as follows:

C trachomatis genotype LGV

Regimens are as follows:

  • Doxycycline 100 mg PO q12h for 21d (first line) 
  • Erythromycin base 500 mg q6h for 21d (second line) or
  • Azithromycin 1 g PO once weekly for 3wk [9]
  • Presumptive treatment should be considered for men who have sex with men (MSM) with proctitis and a positive rectal chlamydia test [10]

T pallidum

Regimens are as follows:

  • Benzathine penicillin G 2.4 million units IM as a single dose (first line)
  • Doxycycline 100 mg PO q12h for 14d (penicillin-allergic) [9] or
  • Azithromycin 2 g PO as a single dose (penicillin-allergic) [9]
  • HIV infection - Benzathine penicillin G 2.4 million units IM as a single dose for early latent syphilis
  • All patients positive for primary or secondary syphilis should also be tested for HIV [9]


For patients with first-time infection, 7- to 10-day regimens are as follows [9] :

  • Acyclovir 400 mg PO q8h or
  • Famciclovir 250 mg PO q8h or
  • Valacyclovir 1 g PO q12h or
  • Acyclovir 200 mg PO 5 times daily (not recommended, because of frequency of dosing)
  • Treatment can be extended if healing is incomplete at 10d

For HIV-infected patients with episodic infection, 5- to 10-day regimens are as follows [9] :

  • Acyclovir 400 mg PO q8h or
  • Valacyclovir 1 g PO q12h or
  • Famciclovir 500 mg PO q12h

Shigella species

Regimens are as follows [11] :

Salmonella, severe disease, presence of vascular prosthesis, or immunocompromised

Regimens are as follows [12, 13] :

  • Trimethoprim-sulfamethoxazole (160 mg/800 mg) 1 DS tablet PO q12h or
  • Ciprofloxacin 500 mg PO q12h or
  • Ceftriaxone 1-2 g IV q24h or
  • Cefotaxime 2 g IV q8h
  • Duration 3-7d (≥14d for immunocompromised patients)
  • Persistent carriers should be treated for 4-6wk
  • Sensitivity testing should be carried out because of a high rate of antibiotic resistance among Salmonella strains
  • Severe disease in immunocompetent patients is characterized by severe diarrhea, high fever, and need for hospitalization

E histolytica

Regimens are as follows [14, 15, 16, 17] :

  • Metronidazole 500-750 mg PO q8h for 5-10d or
  • Tinidazole 2 g PO q24h for 2-3d, followed by an intraluminal agent for 5-10d (paromomycin, diloxanide furoate, cloquinol)

C difficile

In addition to initiating therapy as below, [18, 19, 20] discontinue other antimicrobials as soon as possible.

Mild-to-moderate disease:

Severe disease:

  • Vancomycin 500 mg PO q6h for 10-14d and metronidazole 500 mg IV q8h [22, 21]
  • If there is no clinical improvement, add fidaxomicin 200 mg PO q12h
  • Bezlotoxumab 10 mg/kg infusion as adjunct for high-risk patients [21]
  • Intracolonic vancomycin by enema therapy, 500 mg in 100 mL of saline q6h
  • Intracolonic vancomycin by ileostomy creation and colonic lavage
  • Consider intracolonic therapy if ileus is present [21]

Additional therapeutic options:

  • Fecal microbiota transplantation (FMT) [23]

Additional adjunctive agents:

Diagnostic testing

Diagnostic testing is as follows:

  • Patients with acute proctitis will need anoscopy
  • A Gram-stained smear of any anorectal exudate should be examined for polymorphonuclear leukocytes (PMNs)
  • Patient-collected nucleic acid amplification testing (NAAT) is a preferred diagnostic test for suspected anorectal gonorrhea or chlamydial infection
  • Dark-field examinations and tests to detect T pallidum directly from lesion exudate or tissue are the definitive methods for diagnosing early syphilis
  • HSV diagnosis can be obtained from viral culture, polymerase chain reaction (PCR) assay, or direct fluorescent antibody (DFA) of vesicle discharge or serologic testing
  • Diagnosis of enteric pathogens such as Shigella, Salmonella, Campylobacter, and Yersinia is confirmed by stool culture on selective media
  • Stool microscopy can suggest intestinal amebiasis, but it is not specific for E histolytica; antigen testing, serologic examination, and PCR are all useful for specific detection of E histolytica infection
  • Diagnosis of C difficile is established via a positive laboratory stool test for C difficile toxins; send stool initially for glutamate dehydrogenase (GDH) antigen test and for toxin antibody test for antibody to toxin A and B; if results are indeterminate, send stool for C difficile PCR
  • Clinical criteria for C difficile infection (CDI) - Three or more unformed stools within 24 hours (in the absence of other causes) and a positive stool test or demonstration of pseudomembranous colitis [24]
  • With a suspected or confirmed diagnosis, contact precautions should be instituted and strict handwashing implemented [24]

Special considerations

Special considerations include the following:

  • Supportive treatment is the standard treatment for immunocompetent, healthy individuals with Salmonella, Yersinia, or Campylobacter; normally, these diseases are self-limited
  • Severe cases of proctitis/proctocolitis refractory to medical treatment may call for surgical intervention (subtotal colectomy, total proctocolectomy, loop ileostomy creation, colonical lavage)
  • Complications of C difficile colitis include hypotension, toxic megacolon, bowel perforation, renal failure, and sepsis
  • Partner notification and simultaneous treatment are integral to the treatment of sexually transmitted causes of proctitis and proctocolitis