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Sexually Transmitted Diseases (STD/STI)

The following is a point-of-care summary of the April, 2019 Emergency Medicine Practice journal issue titled Emergency Department Diagnosis and Treatment of Sexually Transmitted Diseases. Click here for access to additional featured content from this issue, as well as subscription information. Subscribe or purchase a single issue and complete the activity to earn 4 AMA PRA Category 1 Credits™. This summary is provided with the permission of our content partner EB Medicine.


  1. History
  2. Chlamydia
  3. Gonorrhea
  4. Syphilis
  5. Bacterial Vaginosis
  6. Granuloma Inguinale
  7. Lymphogranuloma Venereum
  8. Genital Herpes
  9. Human Papillomavirus
  10. Trichomoniasis
  11. Mycoplasma Genitalium
  12. Recommended Treatment Table

1) History: Ask about the 5 P’s

  • Partners
  • Practices
  • Prevention of pregnancy
  • Protection from STDs
  • Past history of STDs
  • The CDC has a publication available to assist healthcare providers with sexual history-taking skills, available here.


  • Organism: Obligate intracellular, gram negative bacerium, chalymdia trachomatis
  • Epidemiology:
    • It is the most common bacterial cause of STDs and the most commonly reported STD with 1.8 million cases in 2018, representing a 19% increase since 2014 (CDC)
  • Symptoms/Findings: Majority are asymptomatic
    • Cervicitis
    • Urethritis
    • Urinary frequency
    • Dysuria
    • Pelvic Inflammatory Disease (PID)
    • Vaginal discharge
    • Fitz-Hugh-Curtis syndrome – peritoneal inflammation, and perihepatitis
    • Epididymitis
    • Prostatitis
    • Proctitis
    • Conjunctivitis
    • Pharyngitis
  • Testing:
    • In women, the sensitivity of nucleic acid amplification testing (NAAT) on urine (92%) appears to be slightly lower than the sensitivity on vaginal samples (97%). Self-taken vulvovaginal swabs are as accurate as clinician-performed tests. In men, the diagnostic test of choice is NAAT of first-catch urine, with urethral swab as a secondary option. NAAT can also be performed on conjunctival swabs.
  • Treatment: (Note: This is for uncomplicated infection, not Pelvic Inflammatory Disease)
    • Primary: (Choose one)
      • Azithromycin 1 g PO x 1 dose
      • Doxycycline 100 mg PO bid x 7 days
    • Secondary: (Choose one)
      • Levofloxacin 500 mg PO x 7 days
      • Ofloxacin 300 mg bid x 7 days
    • Pregnant Women: (Choose one)
      • Azithromycin 1 g PO x 1 dose
      • Amoxicillin 500 mg tid x 7 days
  • Treatment Table


  • Organism: Gram negative diplococci bacterium, Neisseria Gonorrhoeae
  • Epidemiology:
    • Second most commonly reported STD with 583,405 cases in 2018 representing a 63% increase since 2014 (CDC)
  • Symptoms: May be asymptomatic.
    • Cervicitis Mucopurulent vaginal discharge and pruritis Dysuria Frequency PID Bartholinitis Fitz-Hugh-Curtis Syndrome  Epididymitis Urethritis Proctitis Pharyngitis Conjunctivitis Purulent arthritis Tenosynovitis Dermatitis Polyarthralgias Endocarditis Meningitis Osteomyelitis
  • Testing:
    • In women, sensitivity of testing of urine appears to be slightly lower compared with vaginal samples. Self-taken vulvovaginal swabs are as accurate as clinician-performed tests. In men, NAAT of the first-catch urine is the diagnostic test of choice. Both urine and urethral specimens are acceptable, as both specimens demonstrate a sensitivity and specificity > 97%.43
  • Treatment: Regimen listed also includes recommended Chlamydia treatment.
    • Primary:
      • Ceftriaxone 250 mg IM x 1 dose PLUS Azithromycin 1 g PO x 1 dose
      • Ceftriaxone 500 mg IM is now recommended by the CDC (updated 12/2020)
    • Secondary: (Choose one)
      • Cefixime 400 mg PO x 1 dose PLUS Azithromycin 1 g PO x 1 dose
      • Gemifloxacin 320 mg PO x 1 dose PLUS Azithromycin 2 g PO x 1 dose
      • Gentamicin 240 mg IM x 1 dose PLUS Azithromycin 2 g PO x 1 dose
      • Ceftriaxone 250 mg IM PLUS Doxycycline 100 mg PO bid x 7 days
    • Pregnant Women:
      • Same as primary treatment.
      • Doxycycline and gemifloxacin are not recommended in pregnancy.
  • Treatment Table


  • Organism: Spirochete bacterium, treponema pallidum
  • Epidemiology:
    • Primary 35,063 cases in 2018 representing a 71% increase since 2014 (CDC)
    • Congenital 1306 cases in 2018 representing a 185% increase since 2014 (CDC)
  • Symptoms: “The great masquerader” or “the great imitator” due to its wide variety of clinical presentations at various stages of the disease.
  • Sub Types:
    • Primary: single, painless lesion known as the chancre at the site of inoculation about 3 weeks post infection. May resolve spontaneously. 
    • Secondary: rash typically involves the palms of the hands and soles of the feet, with lymphadenopathy. Symptoms occur several weeks after the initial infection
    • Tertiary: gummatous lesions and cardiac involvement, including aortic disease that may not appear until after 20 years of syphilis infection.
    • Latent: Asymptomatic stage. 
    • Neurospyhillis: Can occur at any stage. Symptoms include stroke, altered mental status, cranialnerve dysfunction, and tabes dorsalis
  • Testing:
    • Serologic diagnosis always requires detection of both non-treponemal and treponemal antibodies.
    • The reactivity of nontreponemal tests (RPR, VDRL) declines over time, while the reactivity of treponemal tests (TP-PA or FTA-ABS) persists over a lifetime.
    • Dark-field microscopy, polymerase chain reaction (PCR) and direct fluorescent antibody testing that can directly detect T pallidum, are not widely available in the ED clinical setting.
  • Standard (CDC recommended) algorithm involves:
    • Step 1: Rapid plasma reagin (RPR) or venereal disease research laboratory (VDRL) testing first. If negative, syphilis unlikely. If positive, proceed to step 2 .
    • Step 2: Fluorescent treponemal antibody absorption (FTA-ABS) or T. pallidum passive particle agglutination (TP-PA) assay. If positive, syphilis past or present. If negative, syphilis unlikely. 
  •  A new algorithm utilizing rapid treponemal assays, enzyme immunoassays (EIAs), or chemiluminescence immunoassays (CIAs) enables rapid screening with a treponemal assay first to capture early primary or previously treated disease. Further research is ongoing, however it does seem to improve throughput.
    • Step 1: EIA or CIA. If positive, proceed to step 2. 
    • Step 2: RPR or VDRL. If positive, syphilis past or present. If negative, confirm with step 3. 
    • Step 3: TP-PA. If positive, syphilis past or present. If negative, syphilis unlikely. 
  • Treatment:
    • Preferred:
      • Penicillin G benzathine 2.4 million units IM x 1 dose
    • Alternate: N/A
    • Pregnant Women:
      • Same as preferred treatment
  • Treatment Neurosyphilis:
    • Preferred:
      • Aqueous crystalline penicillin G 18-24 million units daily administered as 3-4 million units every 4 hours or continuous infusion x 10-14 days
    • Alternate:
      • Ideally, penicillin desensitization
      • Doxycycline 200 mg bid x 28 days
      • Ceftriaxone 250 mg IM for 10-14 days
    • Pregnant Women:
      • Same as primary treatment
  • Treatment Table

5)Bacterial Vaginosis

  • Organism: Overgrowth of anaerobic bacteria including Gardnerella vaginalis, Bacteroides spp., Ureaplasma, and Mycoplasma hominis.
  • Epidemiology:
    • Bacterial vaginosis (BV) is not always an STD.
    • Sexual contact is associated with an increased risk of BV.
    • Condom use is associated with a decreased risk.
    • Presence of other STDs also appears to be associated with an increased prevalence of BV.
  • Symptoms: 50% of women with BV are asymptomatic
    • Thin, grayish-white, homogeneous, vaginal discharge often described as having a “fishy” smell.
    • Vaginal pain, dysuria, and dyspareunia are uncommon in patients with isolated BV, but patients may complain of pruritus.
  • Testing: The use of Amsel (4) criteria for the diagnosis of BV is 90% sensitive and 77% specific. 
    • Thin, milky, homogenous vaginal discharge. 
    • Release of fishy odor before or after addition of 10% potassium hydroxide to fluid sample. 
    • Vaginal pH > 4.5 (most sensitive) 
    • Presence of clue cells (most specific)
  • Treatment:
    • Primary: (Choose one)
      • Metronidazole 500 mg PO bid x 7 days
      • Metronidazole gel 0.75%; 1 applicator (5 g) intravaginally daily x 5 days
    • Secondary: (Choose one)
      • Clindamycin cream 2%; 1 applicator (5 g) intravaginally at bedtime x 7 days
      • Oral clindamycin 300 mg PO bid x 7 days
    • Pregnant Women:
      • Same as primary treatment and secondary alternatives
  • Treatment Table

6)Granuloma Inguinale

  • Organism: Cause by Klebsiella granulomatis, also known as donovanosis
  • Epidemiology: 
    • Endemic to India, the Caribbean, central Australia, and southern Africa. Rare in the US.
  • Symptoms: Highly vascular ulcerative lesions on the genitals or perineum that are generally painless and bleed easily, without regional lymphadenopathy. Lesions include:
    • Ulcero-vegetative lesions, the most common, are large, painless, suppurative ulcers. These ulcers are most commonly found in skin folds and appear to have clean, friable bases that bleed easily.
    • Nodular inguinale lesions are often soft and erythematous, and eventually ulcerate.
    • Less commonly cicatricial lesions, which are dry ulcers that evolve into plaques
    • Less commonly hypertrophic lesions.
    • Even though patients with granuloma inguinale typically present with genital ulcers, patients can also have oral, anal, and extragenital infections, with dissemination to intra-abdominal organs or bones. Elephantiasis-like swelling of the external genitalia can also occur in the later stages of granuloma inguinale.
  • Testing: 
    • Formal diagnosis is made by visualization of Donovan bodies on microscopy from a sample obtained from the surface debris from purulent ulcers.
    • All patients in whom this diagnosis is suspected should also be tested for HIV.
  • Treatment:
    • Primary: (Choose one)
      • Azithromycin 1 g PO once/wk until all lesions have healed completely
      • Azithromycin 500 mg PO once daily for at least 3 wk and until all lesions have healed completely
    • Secondary: (Choose one)
      • Doxycycline 100 mg PO bid
      • Ciprofloxacin 750 mg PO bid
      • Erythromycin base 500 mg PO qid
      • In each case, treat for at least 3 wks and until all lesions have healed completely
    • Pregnant Women: (Choose one)
      • Azithromycin 1 g PO once/wk
      • Azithromycin 500 mg PO once daily
      • Erythromycin base 500 mg PO qid
      • In each case, treat for at least 3 wk and until all lesions have healed completely
  • Treatment Table

7)Lymphogranuloma Venereum

  • Organism: Caused by serovars L1, L2, and L3 of Chalmydia trachomatis
  • Infection occurs in the lymphatics and lymph nodes.
  • Epidemiology:
    • Most frequently in tropical and subtropical areas of the world, including Central and South America
    • In the last 10 years, outbreaks have appeared in North America, Europe, and Australia in the form of proctitis among men who have sex with men.
  • Symptoms:
    • Presents with painful inguinal lymphadenopathy.
    • Fluctuant and suppurative lymph nodes, referred to as buboes, may either rupture or develop into hard, non-suppurative masses. The groove sign, a pathognomonic finding of LGV, occurs in 15% to 20% of cases, when the inguinal and femoral lymph nodes are both involved and are separated by the inguinal ligament.
    • Proctitis due to LGV has become more common
  • Testing:
    • NAAT of the base of an ulcer. 
    • Treatment is based on clinical suspicion as results are often not available during the initial ED visit. 
  • Treatment:
    • Primary:
      • Doxycycline 100 mg PO bid x 21 days
    • Secondary: (Choose one)
      • Azithromycin 1 g PO once/wk x 3 weeks
      • Moxifloxacin 400 mg PO daily x 10 days
    • Pregnant Women: (Choose one)
      • Erythromycin base 500 mg PO qid x 3 wk
      • Azithromycin 1 g PO once weekly x 3 wk
  • Treatment Table

8)Genital Herpes

  • Organism: Caused by herpes simplex virus type 1 (HSV-1) or type 2 (HSV-2), a double-stranded DNA virus surrounded by lipid glycoprotein.
  • Epidemiology:
    • It is believed that at least 1 out of every 6 people in the United States between the ages of 14 and 49 years have genital herpes
    • HSV-1 can spread through oral sex, leading to genital herpes. In fact, HSV-1 is increasingly associated with genital infection and has been reported to cause more genital infections than HSV-2, especially in young people and homosexual men.
  • Symptoms:
    • Localized pain, itching, dysuria, and lymphadenopathy.
    • Fever, headache, and malaise, are most prominent in the first 3 to 4 days.
    • Vesicles rupture and form painful ulcers. 
    • Women may have inflamed, edematous vaginal mucosa, cervicitis, and dysuria, leading to urinary retention.
    • Men can present with herpetic vesicles located in the glans penis, the penile shaft, the scrotum, the perianal area, and the rectum.
  • Testing: 
    • Viral culture of vesicular fluid from an unroofed vesicle.
    • Nucleic acid amplification testing (NAAT) is more sensitive and rapid, and is the preferred tests in patients with active genital ulcers.
    • HSV PCR assays also have the ability to differentiate between HSV-1 and HSV-2.
    • Viral shedding is intermittent, so failure to detect HSV does not always indicate the absence of HSV. Refer all patients to their primary care provider for further evaluation and possible further serological testing.
  • Treatment:
    • Primary: (Choose one)
      • Acyclovir 400 mg PO tid x 7-10 days
      • Acyclovir 200 mg PO 5x daily x 7-10 days
      • Valacyclovir 1 g PO bid x 7-10 days
      • Famciclovir 250 mg PO tid x 7-10 days
    • Secondary:
      • N/A
    • Pregnant Women: (Choose one)
      • Acyclovir 400 mg PO tid x 7-10 days
      • Valacyclovir 1 g PO bid x 7-10 days
  • Treatment Table

9)Human Papillomavirus

  • Organism: Double-stranded DNA virus that replicates at the basal cell layer of stratified squamous epithelial cells.
  • Epidemiology:
    • HPV is associated with carcinoma of the penis and is responsible for more than 95% of the cervical cancers in women.
    • HPV types 16 and 18 can lead to cervical,penile, vulvar, vaginal, anal, and oropharyngeal cancers.
    • HPV types 6 and 11, may lead to anogenital warts, also known as condyloma acuminata. These cause changes ranging from hyperplasia to carcinoma.
  • Symptoms: Most infections are asymptomatic, subclinical, or transient, clearing within 2 years in immunocompetent persons.
    • Condylomata acuminata are exophytic “cauliflower-like” lesions or white plaque-like growths, and are the most easily recognized sign of a genital HPV infection.
    • HPV does not cause discharge or dysuria, so evaluation of these symptoms should focus on other potential etiologies.
  • Testing : Diagnosis is clinical. Oncogenic strain testing is typically not performed in the ED as results are not returned rapidly. This should be deferred to the outpatient setting. 
  • Treatment Table


  • Organism: Trichomonas vaginalis is a single-celled, flagellated, anaerobic protozoa.
  • Symptoms: Majority of both women and men with trichomoniasis are asymptomatic.
    • Fothy vaginal discharge
    • Vaginal odor
    • Vulvovaginal irritation and itching
    • Dyspareunia
    • Dysuria
    • Colpitis macularis, also known as a strawberry cervix, is seen by the naked eye in only about 2% to 5% of infected women.
    • Epididymitis
    • Postatitis
    • Urethritis.
  • Testing: 
    • Nucleic acid amplification testing (NAAT) is highly sensitive (95.3%-100%), detecting 3 to 5 times more Trichomonas vaginalis infections than wet-mount microscopy.
    • Antigen-detecting tests are also available. They are less sensitive than NAATs, but more sensitive than wet mounts. 
    • Wet mount microscopy is most common however it is no longer recommended as a first-line evaluation due its low sensitivity. 
  • Treatment:
    • Primary: (Choose one)
      • Metronidazole 2 g PO x 1 dose
      • Metronidazole 500 mg PO bid x 7 days
      • Tinidazole 2 g PO x 1 dose
    • Secondary: N/A
    • Pregnant Women:
      • Same as primary treatment
  • Treatment Table

11)Mycoplasma Genitalium

  • Organisim: Mycoplasma genitalium
  • Symptoms:
    • Nongonococcal urethritis in men
    • Mucopurulent cervicitis and pelvic inflammatory disease (PID) in women.
    • It has the potential to lead to an ascending infection and impact female fertility
  • Testing: No FDA approved diagnostic test exists. 
  • M. genitalium should always be considered in patients presenting with persistent or recurrent urethritis, cervicitis, or PID.
  • Treatment:
    • Primary:
      • Azithromycin 500 mg PO x 1 dose PLUS Azithromycin 250 mg PO once daily x 4 days
    • Secondary:
      • Moxifloxacin 400 mg PO once daily x 7 days
    • Pregnant Women:
      • Same as primary treatment
  • Treatment Table

Recommended Treatment Table


  1. Pfennig-bass CL, Bridges EP. Emergency department diagnosis and treatment of sexually transmitted diseases. Emerg Med Pract. 2019;21(4):1-32.
  2. CDC Sexually Transmitted Diseases Surveillance, 2018 (link , report )

This summary is provided with the permission of our content partner EB Medicine; www.ebmedicine.net