Proctitis is inflammation of the distal rectum (distal 10–12 cm) presenting with rectal bleeding, discharge, tenesmus, urgency, and anorectal pain. [1-2] The two most common etiologic categories are sexually transmitted infections (STIs) and inflammatory bowel disease (IBD), though radiation, ischemia, and medications are also important causes. [3-5]
1. History
- Onset and duration: Acute (<4–6 weeks) favors infectious etiology; chronic/relapsing course suggests IBD [6]
- Symptom characterization: Rectal bleeding (color, volume), mucous or purulent discharge, tenesmus, urgency, anorectal pain, constipation (present in 5–10% of ulcerative proctitis) [4][6]
- Sexual history (critical): Receptive anal intercourse (oral-anal, digital-anal, genital-anal), number of partners, condom use, history of STIs — must be elicited in all patients with proctitis [1][6]
- Radiation history: Prior pelvic radiation (prostate, cervical, rectal, uterine cancer) — onset may be months to years post-treatment [7-8]
- Medication use: NSAIDs, checkpoint inhibitors, recent antibiotics
- Associated symptoms: Fever, night sweats, weight loss, diarrhea, abdominal cramping, skin lesions (mpox vesicles/pustules), inguinal lymphadenopathy, joint pain [9-10]
- Important negatives: Absence of diarrhea (proctitis vs. proctocolitis), no proximal GI symptoms
2. Alarm Features
- High fever (≥38.5°C) with rectal symptoms — concern for systemic infection or bacteremia [11]
- Severe rectal bleeding with hemodynamic instability
- Peritoneal signs or severe abdominal pain — rule out perforation, toxic megacolon
- Rectal mass mimicking malignancy — syphilitic proctitis can present as a mass lesion on CT and endoscopy [10]
- Acute severe colitis criteria (Truelove & Witts): ≥6 bloody stools/day + systemic toxicity (tachycardia, fever, anemia, elevated ESR/CRP) [6]
- Urinary retention — can occur with HSV proctitis (sacral radiculopathy)
- Rapidly progressive symptoms in immunocompromised patients (HIV) — consider CMV, disseminated HSV, or opportunistic infections [1][12]
3. Medications
Medications that may cause or worsen proctitis
- NSAIDs (drug-induced colitis/proctitis) [13-14]
- Checkpoint inhibitors (immune-mediated colitis)
- Antibiotics (C. difficile-associated proctocolitis)
Common treatments by etiology
- Infectious (STI-related): Ceftriaxone 500 mg IM × 1 + doxycycline 100 mg PO BID × 7 days (extend to 21 days if LGV suspected) [1]
- HSV proctitis: Valacyclovir 1 g PO BID × 7–10 days or acyclovir 400 mg PO TID × 7–10 days [1]
- Syphilitic proctitis: Benzathine penicillin G 2.4 million units IM [10]
- Ulcerative proctitis: Mesalamine (5-ASA) suppository 1 g/day (first-line) [14-15]
- Radiation proctitis: Sucralfate enemas, argon plasma coagulation (APC) for refractory bleeding [8][16]
Contraindications/cautions
- Avoid systemic corticosteroids for maintenance in ulcerative proctitis (side-effect profile) [17]
- Avoid empiric immunosuppression before ruling out infectious causes [6]
4. Diet
- Acute phase: Clear liquids or low-residue diet if severe symptoms; maintain hydration
- Radiation proctitis: High-fiber diet has shown improvement in symptoms in some studies [18]
- Ulcerative proctitis: No specific dietary trigger established; individualized approach; avoid known personal triggers
- Infectious proctitis: No specific dietary restrictions; ensure adequate hydration if diarrhea present
5. Review of Systems
- GI: Diarrhea, constipation, abdominal pain, bloating, nausea, hematochezia, mucous discharge
- GU: Urethral discharge, dysuria, genital ulcers/lesions (concurrent STI)
- Dermatologic: Rash (secondary syphilis), vesicles/pustules (HSV, mpox), pyoderma gangrenosum, erythema nodosum (IBD)
- MSK: Arthralgia/arthritis (IBD-associated peripheral arthropathy) [6]
- Ophthalmologic: Eye pain, redness (uveitis/iritis in IBD or reactive arthritis)
- Constitutional: Fever, night sweats, weight loss, fatigue
6. Collateral History and Family History
- Sexual partners: Symptoms in partners, need for partner notification and treatment [9][19]
- Family history: IBD (first-degree relatives), autoimmune conditions, colorectal cancer
- Social context: HIV status, PrEP use, substance use, recent travel, incarceration history
- Occupational: Healthcare workers, daycare (enteric pathogen exposure)
7. Risk Factors
- Receptive anal intercourse (strongest risk factor for infectious proctitis) [1-2]
- Men who have sex with men (MSM) — highest incidence of STI-related proctitis [2-3]
- HIV seropositivity — increased prevalence of HSV, LGV, CMV proctitis [1][12]
- Multiple sexual partners, condomless intercourse [2]
- Prior pelvic radiation (dose >45 Gy increases risk significantly) [7]
- Prior history of IBD or family history of IBD [6]
- Immunosuppression (transplant, chemotherapy) — CMV, opportunistic infections [1]
- NSAID use, recent antibiotic use [13][20]
8. Differential Diagnosis
Infectious (cannot miss)
- Gonococcal proctitis (N. gonorrhoeae) — purulent discharge, often asymptomatic [1]
- Chlamydial proctitis (C. trachomatis) — mild symptoms; LGV serovars cause severe ulcerative proctitis [1]
- Syphilitic proctitis (T. pallidum) — can mimic rectal cancer or IBD with mass-like lesions [10]
- HSV proctitis — severe anorectal pain, perianal vesicles/ulcers, urinary retention [1]
- Mpox proctitis — vesiculopustular perianal lesions, inguinal lymphadenopathy [3][21]
Inflammatory
- Ulcerative proctitis (UC limited to rectum) — chronic relapsing course, rectal bleeding, urgency [4][22]
- Crohn's disease — perianal fistulae, skip lesions, granulomas on biopsy [13]
Other
- Radiation proctitis — history of pelvic radiation, telangiectasias on endoscopy [5][8]
- Ischemic proctitis — older patients, vascular risk factors [23]
- Drug-induced (NSAIDs, checkpoint inhibitors) [13-14]
- Diversion proctitis — post-colostomy/ileostomy [5]
- Rectal cancer — must be excluded, especially when mass-like lesion present [10]
- C. difficile proctocolitis — recent antibiotic use [6]
- Solitary rectal ulcer syndrome [24]
9. Past Medical History
- Prior STIs (gonorrhea, chlamydia, syphilis, HIV)
- IBD diagnosis or prior episodes of proctitis
- History of pelvic radiation or pelvic surgery
- Prior anorectal surgery (hemorrhoidectomy, J-pouch — pouchitis risk ~50% at 10 years) [23]
- Immunosuppressive conditions or medications
- Chronic NSAID use
10. Physical Exam
- Vital signs: Fever (infectious), tachycardia (sepsis, hemorrhage), hypotension (dehydration, hemorrhage)
- Abdominal exam: Tenderness (LLQ in UC), distension, peritoneal signs (perforation)
- Perianal inspection: Ulcers (HSV, syphilis, LGV), vesicles/pustules (HSV, mpox), condylomata, fissures, fistulae (Crohn's), skin tags
- Digital rectal exam: Tenderness, discharge (purulent, bloody, mucoid), masses, sphincter tone
- Anoscopy (recommended by CDC for all suspected acute proctitis): Mucosal erythema, friability, exudate, ulceration [1]
- Inguinal lymphadenopathy: LGV, syphilis, HSV, mpox [9]
- Skin exam: Palmar/plantar rash (secondary syphilis), erythema nodosum, pyoderma gangrenosum (IBD)
- Joint exam: Peripheral arthritis (IBD-associated)
- Eye exam: Conjunctival injection (uveitis in IBD or reactive arthritis)
11. Lab Studies
Infectious workup (per CDC guidelines): [1][21]
- Rectal swab NAAT for N. gonorrhoeae and C. trachomatis
- HSV NAAT (rectal swab of lesions)
- Syphilis serology (RPR/VDRL + confirmatory treponemal test)
- Gram stain of anorectal exudate (PMNs, gram-negative intracellular diplococci)
- Mpox PCR (rectal swab) if vesiculopustular lesions present [21]
- HIV testing (4th-generation Ag/Ab) — all patients with STI-related proctitis [9]
- Consider M. genitalium NAAT if persistent symptoms after standard treatment [1]
IBD/inflammatory workup: [14]
- CBC (anemia, leukocytosis, thrombocytosis)
- CRP, ESR
- Fecal calprotectin (sensitivity 0.89, specificity 0.81 for IBD vs. non-IBD at cutoff 50 μg/g) [14]
- Stool cultures, C. difficile toxin
- Albumin, ferritin, liver enzymes
Labs to rule out dangerous conditions
- Lactate (if sepsis concern)
- Type and screen (if significant hemorrhage)
- CMV PCR or tissue immunohistochemistry (immunocompromised patients) [1][6]
12. Imaging
- Imaging is generally not required for uncomplicated proctitis [23]
- CT abdomen/pelvis: Indicated if concern for complications (perforation, abscess, fistula), mass lesion, or broader differential; may show rectal wall thickening, pericolonic stranding [10][25]
- MRI pelvis: Superior for perianal fistulae (Crohn's), complex pelvic pathology [23]
- Point-of-care transperineal ultrasound (TPUS): Emerging ED tool showing circumferential rectal wall edema; may reduce need for CT in uncomplicated cases [25]
- Important finding: Syphilitic proctitis can mimic metastatic rectal cancer on CT — maintain high suspicion [10]
13. Special Tests
- Anoscopy/proctoscopy: First-line diagnostic procedure per CDC; allows direct visualization and specimen collection [1]
- Flexible sigmoidoscopy/colonoscopy: Indicated for chronic/relapsing symptoms, suspected IBD, or when infectious workup is negative; allows biopsy for histopathology [4][11]
- Histopathology: Chronic architectural changes (crypt distortion, basal plasmacytosis) suggest IBD; granulomas suggest Crohn's or syphilis; viral inclusions suggest CMV [14][26]
- LGV PCR (C. trachomatis serovars L1–L3): Not widely available but confirmatory if positive [1]
- Fecal calprotectin: Useful to differentiate IBD from functional disorders; less helpful in distinguishing infectious from inflammatory proctitis [14][27]
14. ECG
- ECG is not routinely indicated for proctitis
- Consider ECG if:
- Significant hemorrhage with hemodynamic instability (tachycardia, hypotension)
- Severe dehydration with electrolyte abnormalities (hypokalemia risk from diarrhea)
- Sepsis or systemic toxicity
- Pre-procedural assessment if sedation planned for endoscopy
15. Assessment
Severity stratification
- Mild: Intermittent rectal bleeding/discharge, no systemic symptoms, hemodynamically stable
- Moderate: Frequent symptoms, mucosal ulceration, mild systemic symptoms
- Severe: Significant hemorrhage, systemic toxicity (fever, tachycardia), inability to tolerate PO, urinary retention (HSV)
Key clinical pearls
- Infectious proctitis is frequently misdiagnosed as IBD — always obtain sexual history and STI testing before initiating immunosuppressive therapy [2][9][19]
- Syphilitic proctitis can mimic rectal cancer on imaging and endoscopy — biopsy and serology are essential [10]
- Up to 50% of patients with ulcerative proctitis will experience proximal disease extension within 12–24 months [22]
- Co-infections are common in STI-related proctitis — test broadly [9]
16. Treatment Plan
Infectious proctitis (empiric, per CDC 2021): [1]
- Ceftriaxone 500 mg IM × 1 (1 g if ≥150 kg) PLUS doxycycline 100 mg PO BID × 7 days
- Extend doxycycline to 21 days if bloody discharge, perianal/mucosal ulcers, tenesmus + positive rectal chlamydia NAAT (presumptive LGV treatment)
- Add valacyclovir 1 g PO BID × 7–10 days if painful perianal ulcers or vesicles (HSV coverage)
- Syphilis: Benzathine penicillin G 2.4 million units IM (single dose for primary; 3 weekly doses for late/unknown duration) [10]
- Partner notification and treatment for all STI-related cases [9]
- HIV testing for all patients [9]
Ulcerative proctitis: [14-15][17]
- First-line: Mesalamine (5-ASA) suppository 1 g/day (strong recommendation per ACG 2025) [15]
- Second-line (refractory to topical 5-ASA): Tacrolimus suppository or beclomethasone suppository; topical corticosteroid foam/enema [15][17]
- Refractory: Oral budesonide MMX 9 mg/day; escalation to immunomodulators or biologics with GI consultation [15][28]
Radiation proctitis: [8][16]
- Mild/self-limiting: Observation, antidiarrheals, hydration
- Rectal bleeding: Sucralfate retention enemas (2 g in 20 mL water BID) — moderately effective [8]
- Refractory bleeding: Argon plasma coagulation (APC) — effective short-term; topical 4% formalin application (comparable efficacy to APC) [8][29]
- Severe/refractory: Hyperbaric oxygen therapy; surgery reserved for hemorrhage, obstruction, fistula, or perforation [30-31]
17. Disposition
Discharge criteria (majority of cases)
- Hemodynamically stable, tolerating PO
- Uncomplicated infectious proctitis — treat empirically and discharge with follow-up [1]
- Mild ulcerative proctitis — initiate topical 5-ASA, arrange GI follow-up
- Mild radiation proctitis — outpatient management with sucralfate enemas
Admission criteria
- Hemodynamic instability or significant hemorrhage requiring transfusion
- Acute severe ulcerative colitis (Truelove & Witts criteria) — IV steroids ± salvage therapy [6][24]
- Systemic toxicity/sepsis (high fever, tachycardia, peritoneal signs)
- Inability to tolerate oral intake or medications
- Urinary retention (HSV proctitis with sacral radiculopathy)
- Suspected perforation, abscess, or toxic megacolon
Specialist consultation triggers
- GI: Suspected IBD, refractory proctitis, need for endoscopy/biopsy
- Infectious disease: Complex STI cases, HIV-positive patients with opportunistic infections, persistent symptoms after empiric therapy
- Surgery: Perforation, obstruction, fistula, uncontrolled hemorrhage
- Radiation oncology: Chronic radiation proctitis management
18. Follow Up / Return Precautions
Follow-up timing
- Infectious proctitis: Return in 7–14 days for test-of-cure (especially gonorrhea/chlamydia); ensure partner treatment [1]
- Ulcerative proctitis: GI follow-up within 4–8 weeks to assess response to topical 5-ASA; colonoscopy for definitive diagnosis [15]
- Radiation proctitis: GI follow-up within 2–4 weeks; repeat endoscopy if bleeding persists [8]
Return precautions — instruct patients to return immediately for:
- Worsening rectal bleeding or passage of large blood clots
- High fever, rigors, or feeling severely unwell
- Inability to urinate
- Severe abdominal pain or distension
- Inability to tolerate fluids or medications
- New skin lesions spreading (mpox concern)
Patient counseling
- Abstain from sexual contact until treatment is completed and symptoms resolve (infectious proctitis) [1]
- Ensure all sexual partners are notified and treated
- Adherence to topical mesalamine is critical — symptoms may take up to 8 weeks to fully resolve in ulcerative proctitis [13]
- Proximal constipation is common in ulcerative proctitis and may cause bloating/pain unrelated to active inflammation — osmotic laxatives can help [24]
References
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