Chlamydia: Silent Infection, Serious Consequences

Chlamydia trachomatis is the most reported bacterial STI globally. Up to 70–80% of women and 50% of men are asymptomatic, enabling silent transmission and delayed complications.

Natural History if Untreated

• Women: Cervicitis → endometritis → salpingitis (PID) → tubal scarring → infertility (10–20% after 1 episode), ectopic pregnancy (7–10× risk), chronic pelvic pain.
• Men: Urethritis → epididymitis → infertility (rare), reactive arthritis.
• Both: Proctitis, conjunctivitis, reactive arthritis (Reiter's syndrome).
• Perinatal: Neonatal conjunctivitis, pneumonia.

Transmission Dynamics

• Asymptomatic carriers transmit efficiently—driving high prevalence.
• Condoms reduce but don't eliminate risk (mucosal contact outside coverage).
• Reinfection common; partner treatment essential (expedited partner therapy available in many jurisdictions).

Screening & Diagnosis

• NAAT (nucleic acid amplification test) on urine (men), vaginal swab (women, self-collected), rectal/pharyngeal swabs (MSM).
• CDC screening recs: All sexually active women <25 annually; older women with risk factors; pregnant women at first visit; MSM at exposed sites annually.

Treatment

• Doxycycline 100 mg PO BID × 7 days (preferred, non-pregnant).
• Azithromycin 1 g PO single dose (alternative; pregnancy-safe).
• Abstain 7 days after treatment + partner treated.
• Test-of-cure at 3–4 weeks if pregnant, persistent symptoms, or adherence concerns.
• Retest at 3 months (high reinfection rate).

Early detection and treatment prevent irreversible reproductive damage.