What is Chlamydia?
Chlamydia is the most common sexually transmitted bacterial infection worldwide, caused by Chlamydia trachomatis, which often presents asymptomatically but can lead to serious reproductive health complications including pelvic inflammatory disease, infertility, and ectopic pregnancy. 1
Epidemiology
- Most commonly reported sexually transmitted infection in the United States 1
- Estimated 3 million new infections annually in the US, with actual numbers likely higher due to underreporting 1
- Highest prevalence in sexually active young adults, particularly those under 25 years of age 1
- More common in African-American and Hispanic populations 1
Clinical Presentation
In Women
- 70-90% of infections are asymptomatic 1
- When symptomatic, may present with:
- Cervicitis
- Urethritis
- Abnormal vaginal discharge
- Irregular bleeding
- Dyspareunia (painful intercourse)
In Men
- Often asymptomatic or with mild symptoms 1, 2
- When symptomatic, may present with:
- Urethral discharge
- Dysuria (painful urination)
- Symptoms similar to gonorrhea but typically milder 1
In Infants
- Can be transmitted during vaginal delivery from infected mothers 1
- May cause neonatal conjunctivitis (15-25% of exposed infants) 1
- May cause pneumonia (3-16% of exposed infants) 1
- C. trachomatis is the most common cause of neonatal conjunctivitis 1
Complications
In Women
- Pelvic inflammatory disease (PID)
- Chronic pelvic pain
- Tubal factor infertility
- Ectopic pregnancy
- Perihepatitis (Fitz-Hugh-Curtis syndrome) 1
- Increased risk of HIV acquisition 1
In Men
- Epididymitis
- Nongonococcal urethritis (NGU)
- Reactive arthritis (Reiter's syndrome)
- Proctitis in men who engage in receptive anal intercourse 1, 2
- Rarely: urethral strictures 1
Diagnosis
- Nucleic acid amplification tests (NAATs) are the preferred diagnostic method due to high sensitivity and specificity (82-100%) 1
- Can be performed on:
- Endocervical or urethral swab specimens
- Urine specimens (allowing non-invasive testing)
- Older methods include antigen detection tests (EIA, DFA) with slightly lower sensitivity (70-80%) 1
Treatment
- Recommended regimens:
- Azithromycin (single dose) or
- Doxycycline (7-day course) 3
- Treatment of sexual partners is essential to prevent reinfection 2
- Patients should be tested for other STIs including gonorrhea, syphilis, and HIV 2
Prevention
- Regular screening of high-risk populations, particularly sexually active women under 25 1
- Condom use provides protection against transmission 4
- Treatment of infected individuals and their partners 1
- Public health education about symptoms and transmission
Screening Recommendations
- All sexually active women age 24 years or younger should be screened 1
- Older women with risk factors (new or multiple sexual partners, inconsistent condom use) should be screened 1
- Pregnant women with risk factors should be screened 1
- Screening high-risk men is a clinical option, though focus should be on improving screening rates among women 1
Chlamydia remains a significant public health concern due to its high prevalence and potential for serious complications, particularly in women. Early detection and treatment are crucial to prevent long-term sequelae and reduce transmission.