The information below is based on British Association for Sexual Health & HIV (BASHH) Guidelines: Chlamydia trachomatis (updated September 2018).

Genital chlamydial infection can cause significant short and long-term morbidity. Complications of infection include pelvic inflammatory disease (PID), tubal infertility, ectopic pregnancy, epididymo-orchitis, and lymphogranuloma venereum (LGV).

Chlamydia is the most commonly reported curable bacterial STI in the UK. The highest prevalence rates are in 15–24-year olds. Chlamydia infection has a high frequency of transmission, with concordance rates of up to 75% of partners being reported.

Risk factors for chlamydia infection include:

• Age under 25 years
• A new sexual partner
• More than one sexual partner in the last year
• Lack of consistent condom use
• Social deprivation

If chlamydia infection is suspected or confirmed, strongly recommend referral to a Genito-Urinary Medicine (GUM) clinic for management.

• Devon Sexual Health (Barnstaple, Exeter, and Torquay)
• SHiP (Sexual Health in Plymouth)

If the person declines, or is unable to attend a GUM clinic, manage in primary care.

Symptoms

At least 70% of women and 50% of men infected with chlamydia trachomatis are asymptomatic, and symptoms in men can be very mild.

Suspect chlamydia in sexually active women with:

• Increased vaginal discharge
• Post-coital and intermenstrual bleeding
• Dysuria
• Lower abdominal pain
• Deep dyspareunia

Suspect chlamydia in sexually active men with:

• Urethral discharge
• Dysuria

Symptoms of rectal chlamydia include anal discharge and anorectal discomfort, although rectal infection is usually asymptomatic.

Pharyngeal infections are usually asymptomatic.

Screening

Asymptomatic people who should be tested for chlamydia include:

• Sexual partners of those with proven or suspected chlamydial infection
• All sexually active people younger than 25 years of age, annually, or more frequently if they have changed their partner
• All people with concerns about a sexual exposure.
  • If the exposure was within the last two weeks, a test should be carried out at presentation and if negative, repeated two weeks after the exposure.
• People under the age of 25 years who have been treated for chlamydia in the previous three months
• People who have had two or more sexual partners in the previous 12 months
• All women seeking termination of pregnancy
• All men and women attending genito-urinary medicine clinics

Public Health England recommend opportunistic screening of all patients aged 15-24 years.

Test of Cure (TOC)

TOC is not routinely recommended for uncomplicated genital chlamydia infection, because residual, non-viable chlamydial DNA may be detected by nucleic acid amplification test (NAAT) for 3-5 weeks following treatment.

TOC is recommended in pregnancy, where LGV (in the absence of a definite negative result) or poor compliance is suspected, where symptoms persist, and in rectal infection when one-week doxycycline are used.

TOC should be performed no earlier than three weeks after completion of treatment.

Recommended antibiotic treatment

Uncomplicated urogenital infection, pharyngeal infection, and rectal infection

Doxycycline and ofloxacin are contraindicated in pregnancy and breast-feeding; see below for specific recommendations for pregnancy.

Doxycycline

• 100mg twice daily for 7 days

See section: 5.1.3 Tetracyclines

If intolerant to tetracyclines

Azithromycin

• 1g single starting dose (2 x 500mg tablets), then 500mg daily for 2 days (off-label dose)

See section: 5.1.5 Macrolides

If the above treatments have failed, will not work due to resistance, or are unsafe to use in an individual patient

Ofloxacin

• 200mg twice daily for 7 days or 400mg (2 x 200mg tablets) once daily for 7 days
• Not recommended for use in children and growing adolescents
• Systemic fluoroquinolones must now only be prescribed when other commonly recommended antibiotics are inappropriate (see MHRA Drug Safety Updates below)
• Patients should be advised to stop treatment at the first signs of a serious adverse reaction, such as tendinitis or tendon rupture, muscle pain, muscle weakness, joint pain, joint, feet, or abdomen swelling, peripheral neuropathy, rapid onset of shortness of breath, new-onset of heart palpitations, and central nervous system effects: including new or worsening depression or psychosis, and to seek immediate medical attention.

Pregnancy

Azithromycin and erythromycin in pregnant women have similar efficacy in treating chlamydia. Azithromycin is much better tolerated than erythromycin but should only be used during pregnancy if the benefit outweighs the risk.

Azithromycin

• 1g single starting dose (2 x 500mg tablets), then 500mg daily for 2 days (off-label dose)
• BASHH recommend that women are advised there is a lack of data on pregnancy outcomes using this dosing regimen. The BNF advises to use only if adequate alternatives are not available.

See section: 5.1.5 Macrolides

OR

Erythromycin

• 500mg twice daily for 14 days or 500mg four times daily for 7 days

See section: 5.1.5 Macrolides

OR

Amoxicillin

• 500mg three times a day for 7 days
• Amoxicillin has a similar cure rate to erythromycin and a better side effect profile however, penicillin in vitro has been shown to induce latency and re-emergence of infection

See section: 5.1.1 Penicillins