← Issue №5/ week of Aug 2, 2026/Colorectal

Mechanisms, management and prevention of anorectal sexually transmitted infections.

From GI Signals issue №5: what this paper found, what it changes, and where it sits against the current standard of care, reviewed by Simon Mathews, MD.

Colorectal review · Jul 31, 2026 · Nat Rev Gastro Hep · IF 57.5

Mechanisms, management and prevention of anorectal sexually transmitted infections.

New evidenceepidemiologyartificial intelligencebiomarkerbasic science
Clinical takeawayConsider routine anorectal STI screening in MSM, even if asymptomatic, given high prevalence and silent persistence. For prevention, discuss doxycycline PEP (reduces chlamydia/syphilis incidence) where appropriate, acknowledging practical implementation challenges in diverse clinical settings.
What it foundAnorectal STIs (chlamydia, gonorrhea, syphilis) are often asymptomatic, particularly among men who have sex with men (MSM), with prevalence exceeding urogenital infections.
ContextConfirms the need for proactive screening in high-risk groups, despite existing molecular diagnostics, due to asymptomatic carriage and rising incidence globally.
Reinforcessuggested applicable standard· CDC (Workowski KA, Bachmann LH, Chan PA, et al.), Sexually Transmitted Infections Treatment Guidelines, 2021, Proctitis, Proctocolitis, and Enteritis; MMWR Recommendations and Reports 2021;70(RR-4):1-187

Decision at stakeempiric treatment for acute proctitis in patients with receptive anal exposure

Give empiric ceftriaxone 500 mg IM once plus doxycycline 100 mg BID for 7 days presumptively while awaiting results, started whenever the presentation is consistent with acute proctitis (anorectal exudate on exam or polymorphonuclear leukocytes on a Gram-stained anorectal smear, or, if anoscopy/Gram stain is unavailable, in a patient reporting receptive anal exposure) rather than only once symptoms are "moderate-severe", then tailor therapy by pathogen (extend doxycycline to the full 21-day course presumptively for LGV when bloody discharge, perianal or mucosal ulcers, or tenesmus accompany a positive rectal chlamydia NAAT, rather than waiting for confirmed LGV; penicillin G benzathine for syphilis, antivirals for HSV).

From our summary of this standard, unedited — the part the paper bears on. marks omitted text. Our wording, not the guideline's; read the source for its own text.

Our full summary of this standard

In a patient with proctitis symptoms and receptive anal sex history, test with rectal NAAT for gonorrhea and chlamydia (LGV testing if positive), syphilis serology, HSV PCR from ulcers, stool studies for enteric pathogens in proctocolitis, plus HIV and hepatitis testing. Give empiric ceftriaxone 500 mg IM once plus doxycycline 100 mg BID for 7 days presumptively while awaiting results, started whenever the presentation is consistent with acute proctitis (anorectal exudate on exam or polymorphonuclear leukocytes on a Gram-stained anorectal smear, or, if anoscopy/Gram stain is unavailable, in a patient reporting receptive anal exposure) rather than only once symptoms are "moderate-severe", then tailor therapy by pathogen (extend doxycycline to the full 21-day course presumptively for LGV when bloody discharge, perianal or mucosal ulcers, or tenesmus accompany a positive rectal chlamydia NAAT, rather than waiting for confirmed LGV; penicillin G benzathine for syphilis, antivirals for HSV). Include partner notification and treatment, sexual health counseling, and repeat STI testing at 3 months.

CDC (Workowski KA, Bachmann LH, Chan PA, et al.), Sexually Transmitted Infections Treatment Guidelines, 2021, Proctitis, Proctocolitis, and Enteritis; MMWR Recommendations and Reports 2021;70(RR-4):1-187 · reviewed 2026-07-23 ↗
Latt PM … Chow EPF · Nature Reviews Gastroenterology & Hepatology · IF 57.5 · PubMed ↗Permalink
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