What is the recommended evaluation and treatment for transverse colitis in a man who has sex with men?

Transverse Colitis in Men Who Have Sex With Men

In a man who has sex with men presenting with transverse colitis, you must first rule out sexually transmitted infections (STIs)—particularly Chlamydia trachomatis, Neisseria gonorrhoeae, herpes simplex virus, syphilis, and lymphogranuloma venereum (LGV)—before diagnosing inflammatory bowel disease, as infectious proctocolitis can extend proximally and mimic IBD both clinically and endoscopically.

Evaluation Algorithm

Initial Assessment

• Sexual history is mandatory: Specifically ask about receptive anal intercourse, number of partners, condom use, and HIV status 1, 2
• Recognize the clinical overlap: STI-related proctocolitis and IBD present identically with bloody diarrhea, tenesmus, urgency, abdominal pain, and rectal discharge 3, 4

Diagnostic Testing Required

Perform comprehensive STI screening regardless of endoscopic appearance:

• Rectal swab for NAAT: Test for C. trachomatis and N. gonorrhoeae 5, 2
• Serology: Syphilis (RPR/VDRL), HIV, HSV 1
• LGV-specific testing: If available, particularly if severe symptoms or lymphadenopathy present 6
• Stool studies: Rule out Shigella, Campylobacter, Entamoeba histolytica if diarrhea extends beyond rectum 1
• CMV testing: Especially if HIV-positive 7

Critical pitfall: 86% of MSM with proctitis symptoms have identifiable STIs 4. Standard culture methods are insufficiently sensitive—NAATs are essential 5. Many clinicians fail to obtain sexual history (87% in one study) leading to misdiagnosis as IBD 8.

Endoscopic Findings Cannot Differentiate

Both infectious proctocolitis and IBD show:

• Loss of vascular pattern
• Edema and erythema
• Ulceration and exudation
• Mucosal nodularity 3, 9

Do not rely on endoscopy alone to exclude infection.

Treatment Approach

Empiric Therapy While Awaiting Results

For suspected infectious proctocolitis in MSM, treat empirically 1, 4:

• Ceftriaxone 250 mg IM single dose (for gonorrhea)
• PLUS Doxycycline 100 mg orally twice daily for 7 days (for chlamydia) 5, 2

If LGV suspected (severe symptoms, lymphadenopathy, systemic illness):

• Doxycycline 100 mg orally twice daily for 21 days 6

Response Assessment

• Infectious proctocolitis responds rapidly to appropriate antibiotics (within 3-7 days) 4, 9
• Lack of response after 2 weeks suggests either:
  • Wrong diagnosis (true IBD)
  • Resistant organism
  • Coinfection with multiple pathogens 7

Partner Management

• All sexual partners within 60 days must be treated empirically 5
• Patient should abstain from sexual activity until 7 days after completing single-dose therapy or after completing 7-day regimen 5

Special Considerations

HIV Status

• HIV-positive patients may have more severe disease and atypical organisms (CMV, mycobacteria) 1, 7
• PrEP use correlates with increased STI risk due to decreased condom use 6

Multiple Coinfections

• 11-14% have multiple simultaneous STIs 4, 7
• Test for all pathogens, not just the most likely

When to Consider IBD

Only diagnose IBD after:

1. Negative comprehensive STI testing
2. Failed empiric antibiotic trial
3. Persistent symptoms beyond 2-4 weeks of appropriate treatment
4. Colonoscopy showing disease extent beyond what STIs typically cause

The key error is assuming IBD without excluding infection—this leads to inappropriate immunosuppression that worsens infectious proctocolitis 3, 9, 8.