Sexually Transmitted Infections (STIs)

  1. In a patient who is sexually active or considering sexual activity, take advantage of opportunities to advise her or him about prevention, screening, and complications of sexually transmitted diseases (STIs).

  2. In a patient with symptoms that are atypical or non-specific for STIs (dysuria, recurrent vaginal infections):

    1. Consider STIs in the differential.

    2. Investigate appropriately.

  3. In high-risk patients who are asymptomatic for STIs, screen and advise them about preventive measures.

  4. In high-risk patients who are symptomatic for STIs, provide treatment before confirmation by laboratory results.

  5. In a patient requesting STI testing:

    1. Identify the reasons for testing.

    2. Assess patient’s risk.

    3. Provide counseling appropriate to risk (i.e., human immunodeficiency virus [HIV] infection risk, non-HIV risk)

  6. In a patient with a confirmed STI, initiate:

    • treatment of partner(s).

    • contact tracing through a public health or community agency.

  1. Use appropriate techniques for collecting specimens.

  2. Given a clinical scenario that is strongly suspicious for an STI and a negative test result, do not exclude the diagnosis of an STI (i.e., because of sensitivity and specificity problems or other test limitations).

General Overview

  • Assess reason for consultation

  • Ensure confidentiality


  • Genital symptoms - discharge, dysuria, abdominal pain, testicular pain, skin changes

  • Systemic symptoms - fever, weight loss, lymphadenopathy

  • The Five Ps:

    • Partners (past year)

    • Practices (vaginal, oral, anal, other)

    • Prevention

      • STI - condom use, Hep A/B vaccination

    • Pregnancy/contraception

    • Previous STI testing

  • IVDU

  • Exchange money/drugs for sex

  • LMP, Pap

  • Risk factors (below)

STI Risk Factors

    • Previous STI

    • Sexual contact with person(s) known STI

    • Sexually active <25yo

    • New sexual partner

    • >2 sexual partners in last year or serial one-partner relationships

    • No barrier contraception use

    • IVDU

    • Homelessness

    • Substance use, especially if associated with sex

    • Sex workers

    • Sexual assault

Physical Examination

  • Vitals, temperature

  • Oropharynx: Mucocutaneous lesions

  • Inguinal lymph nodes

  • External genitalia - lesions, inflammation, discharge

  • Perianal inspection

    • Anoscopy/DRE if receptive anal intercourse and rectal symptoms

  • Scrotum - palpate testes, epididymis

  • Pelvic exam

    • Bimanual for uterine/adnexal tenderness

    • Speculum

Appropriate screening/testing

  • Gonorrhea/Chlamydia NAAT PCR (first catch urine, urethral, vaginal, cervical, pharynx, rectal)

    • If symptomatic, add Gonorrhea culture

      • All Gonorrhea should have culture prior to treatment due to increasing resistance

    • Swab all areas of sexual contact (except no need for chlamydia testing in pharynx)

  • VDRL (Nontreponemal RPR or VDRL vs. Treponemal-specific EIA or FTA-ABS)

  • HIV serum EIA (detected at 3w with new generation test, but may take up to 6mo with older tests), western blot to confirm

    • Post-exposure baseline

      • Prophylaxis (Truvada plus raltegravir 400mg PO BID x 28d) if known HIV (or high-risk, eg. sex worker, MSM, IVDU)

        • Re-test HIV 6w, 12w after exposure

  • HBV (if no vaccine) - HBsAg, HBsAb, HBcAb

    • Post-exposure baseline serologies (ensure HBsAb immune)

      • Vaccinate

        • Immunoglobulin if contact known HepBsAg positive

      • Repeat serology 2 months after vaccine series

  • HCV - HCV Ab (IVDU or MSM)

    • Post-exposure baseline HCV Ab

      • HCV RNA 3w after exposure (or HCV Ab 6 months after exposure)

Window period

  • Repeat testing at 6w, 12w, 6mo in the case of sexual assault

    • 1w - Gonorrhea

    • 2w - Chlamydia

    • 12w - Syphilis, HIV, HBsAg /HCV Ab

Diagnosis and post-test counselling

  • Organism/syndrome-specific advice

  • Safe sex practices

  • Treatment information - curable (bacterial) vs. manageable (virus)

  • Motivational interviewing as above


  • Code K ( Patient), Code L (Partner)

    • Gonorrhea: Ceftriaxone 500mg IM x1 as per CDC 2020 guidelines (or alternative: Cefixime 800mg PO x1)

      • If weight ≥150kg (300lb), Ceftriaxone 1g IM is recommended

      • Treat concurrently for chlamydia if chlamydial coinfection not excluded

    • Chlamydia: Doxycycline 100mg PO BID x7d or Azithromycin 1g PO x1

      • Doxycycline PO preferred for rectal chlamydia

      • Azithromycin PO preferred in pregnancy

  • Syphilis

    • Primary, secondary, and early latent syphilis:

      • Pen G 2.4 million units IM x1

    • Late latent (>1y from likely infection) or tertiary (gummatous or cardiovascular disease):

      • Pen G 2.4 million units IM once weekly x 3 weeks

    • Tertiary neurosyphilis

      • Pen G 3-4 million units IV q4h x 10-14d

  • Trichomoniasis (green-yellow malodorous discharge, burning, dyspareunia)

    • Metronidazole 2g PO x1

    • Treat partner

  • Bacterial STI or trichomonas should abstain from unprotected sex until 7d after treatment of both partners complete

  • HSV1 (gingovostomatitis +/- pharyngitis, then recurrent herpes labialis)

    • Initial (within 72h or ongoing new lesions/pain): Acyclovir 400mg PO TID, Famciclovir 500mg PO TID , Valacyclovir 1000mg PO BID x 7-10d

      • If severe odynophagia, consider IV acyclovir

    • Recurrent episodic: Famciclovir 1500mg PO x 1 dose or Valacyclovir 2g PO BID x 1 day

    • Chronic: Acyclovir 400mg PO BID or Valacyclovir 500mg PO daily

  • HSV2 (genital herpes simplex)

    • Initial (within 72h or ongoing new lesions/pain): Acyclovir 400mg PO TID, Famciclovir 250mg PO TID , Valacyclovir 1000mg PO BID x 7-10d

    • Recurrent episodic: Acyclovir 800mg PO TID x2d, Famciclovir 1000mg PO BID x 1 day, Valacyclovir 500mg PO BID x3d

    • Chronic suppressive: Valacyclovir 500-1000mg PO daily

  • HPV

    • Imiquimod 5% cream qHS 3/week x 15w, wash off after 6-10h

    • Podofilox 0.5% solution BID x3d then none x4d, repeat PRN x4

    • Cryotherapy

  • BV (white-grey malodorous discharge, no dyspareunia)

    • Metronidazole 500mg PO BID x7-14d or gel

  • Candidiasis (pruritus, soreness, white clumpy- normal pH 4-4.5)

    • Fluconazole 150mg PO x1 or topical cream/intravaginal/suppository (clotrimazole, miconazole)

Reporting to public health and partner notification

  • Explore barriers to partner notification (feared of abuse, losing partner, legal procedures, anonymity)

    • Traceback

      • Gono/chlam up to 60 days (or last partner if no sexual partners)

      • Longer if syphilis, Hep B, HIV


  • Presumptive treatment of partners within

    • 90d for syphilis (if >90d can test first)

    • 60d of symptoms (or most recent if >60d) for gono/chlam

    • Current sex partners for trichomoniasis

    • Notify HIV partners and PEP offered if within exposure within 72h

  • Refrain from sexual activity for 7d post-treatment (and 7d post-treatment for all partners) and resolution of symptoms

  • Managing comorbidity and associated risks

    • Consider Hep A/B vaccinations in MSM or high risk

  • Resolution of symptoms

  • Follow-up testing as indicated

    • Chlamydia (PCR >3w after treatment)

      • Persistent symptoms

      • Re-exposure

      • Pregnancy

      • Poor adherence

      • Alternate antibiotic use (eg. Azithromycin to treat rectal)

      • Chlamydia genotype L

    • All gonorrhea given increasing resistance (PCR >2w after treatment, or culture >3d after treatment)

    • Syphilis

      • Primary, secondary, early latent infection: Repeat serology at 1, 3, 6 and 12 months after treatment

      • Late latent: Repeat serology 12 and 24 months after treatment

  • Follow-through on partner notification

Patient-centered education and counselling

  • Access to condoms, how to use condoms, signs of STIs and how to get tested/treated

  • Motivational interviewing for condom use

    • Scalify 1-10, how important is it to you to always use condoms?

      • Why X, and not lower?

    • Scalify 1-10, how confident are you that you (and your partner) could always use condoms?

      • Why X, and not lower?

    • What would it take for you to become more confident that you could always use condoms?

  • Promote STI testing for patient and partners before cessation of condom use (particularly when prescribing OCP)

Pelvic inflammatory disease

  • Suspect in sexually active women with pelvic/lower abdominal pain and one of: Adnexal, cervical motion, uterine tenderness

    • Additional criteria to increase specificity

      • Abnormal cervical or vaginal mucopurulent discharge or cervical friability

      • Positive Chlamydia/Gonorrhea

      • Oral T>38.3

      • Abundant WBC (>15 WBC per hpf) on saline microscopy of vaginal secretions

      • Elevated ESR/CRP (less specific)

    • Confirm with pelvic imaging (ultrasound, CT, MRI)


  • Mild-moderate with Ceftriaxone 250mg IM x1 + Doxycycline 100mg PO BID x 14d (+/- Metronidazole for T vaginalis or anaerobic coverage for recent instrumentation)

  • Severe or complicated (eg. tubo-ovarian abscess) with Clindamycin 900mg IV q8h + Gentamicin 1.5mg/kg IV q8h x 14d (step down to Doxycycline)

    • Consider treating male partners if sexual contact 60d prior (or if >60d, most recent) to patient's onset of symptoms (eg. Ceftriaxone 250mg IM, PLUS Azithromycin 1g PO x1 or Doxycycline 100mg PO BID x 7d)

  • Avoid sex until patient and partners adequately treated and asymptomatic

  • Re-assess if need to remove IUD 3d post -treatment