Genital Ulcer Evaluation and Management
For any patient presenting with a genital ulcer, immediately obtain serologic testing for syphilis (mandatory), perform darkfield examination or direct immunofluorescence for Treponema pallidum, culture or PCR for herpes simplex virus, and consider culture for Haemophilus ducreyi if chancroid is endemic in your area—then treat empirically based on clinical presentation while awaiting results, prioritizing treatment for syphilis or both syphilis and chancroid if the diagnosis is uncertain. 1, 2
Initial Diagnostic Approach
The critical reality is that clinical diagnosis based on history and physical examination alone is often inaccurate, and even after complete testing, 25% of genital ulcer patients will have no laboratory-confirmed diagnosis 2. This makes systematic testing essential.
Mandatory Testing for All Patients:
- Serologic test for syphilis (non-negotiable for every patient)
- Darkfield microscopy or direct immunofluorescence for T. pallidum
- Culture or PCR for HSV (herpes simplex virus)
- Culture for H. ducreyi (chancroid) - particularly in areas where chancroid is prevalent 1, 2
Critical HIV Considerations:
HIV testing must be performed at initial diagnosis for patients with genital ulcers, especially those with syphilis or chancroid, as genital ulcers significantly increase HIV transmission risk 1, 2. Retest at 3 months if initial results are negative 1.
Empiric Treatment Strategy (Before Test Results Available)
Since you often must treat before laboratory confirmation, use this algorithmic approach:
If Diagnosis is Clear Clinically:
Treat for the most likely diagnosis based on presentation
If Diagnosis is Uncertain:
Treat for syphilis alone, OR treat for both syphilis and chancroid if:
- Patient resides in a community where chancroid is endemic
- Diagnostic capabilities for chancroid or syphilis are suboptimal 2
This dual-treatment approach is particularly important because 10% of chancroid patients may be coinfected with T. pallidum or HSV 1, 2.
Specific Clinical Presentations
Chancroid (Painful Ulcer):
Clinical clues: Painful genital ulcer(s) with tender inguinal adenopathy (one-third of patients). When accompanied by suppurative inguinal adenopathy, this is almost pathognomonic for chancroid 1, 2.
Probable diagnosis criteria (when culture unavailable):
- One or more painful genital ulcers
- No evidence of T. pallidum by darkfield OR negative syphilis serology at ≥7 days after ulcer onset
- Clinical presentation not typical for HSV OR negative HSV test 1, 2
Treatment options 2:
- Azithromycin 1 g PO single dose (preferred for adherence), OR
- Ceftriaxone 250 mg IM single dose (preferred for adherence), OR
- Ciprofloxacin 500 mg PO twice daily × 3 days (contraindicated in pregnancy, lactation, age ≤17 years), OR
- Erythromycin base 500 mg PO four times daily × 7 days
Critical follow-up: Re-examine at 3-7 days. Ulcers should improve symptomatically within 3 days and objectively within 7 days. If no improvement, consider: wrong diagnosis, coinfection with another STD, HIV infection, non-adherence, or antimicrobial resistance 1, 2.
Genital Herpes (Most Common in US):
Genital herpes is the most prevalent cause of genital ulcers in most US areas 2. HSV-2 causes most cases, though HSV-1 is increasingly recognized 3.
Key diagnostic point: Most infected persons never recognize symptoms—only 13% of HSV-2 seropositive persons have been diagnosed 3.
Testing: Use type-specific molecular or virologic tests when ulcers present; type-specific serology when lesions absent 3.
Syphilis:
Darkfield examination or direct immunofluorescence plus serologic testing required. Treatment with penicillin G benzathine per standard syphilis protocols 4.
Common Pitfalls to Avoid
Never rely on clinical diagnosis alone—the appearance of genital ulcers is notoriously unreliable 2
Don't forget coinfection—3-10% of patients have multiple simultaneous infections 1
HIV-infected patients require special attention: They may not respond as well to treatment, may need longer therapy courses, and healing is slower 1. Consider the 7-day erythromycin regimen for chancroid in HIV-positive patients 1.
Uncircumcised men heal more slowly, particularly with ulcers under the foreskin 2
Consider non-infectious causes when infectious workup is negative: sexual trauma, psoriasis, Behçet syndrome, fixed drug eruptions, inflammatory bowel disease 5, 4, 6
Partner Management
Sexual contacts within 10 days before symptom onset should be examined and treated presumptively, even if asymptomatic 1. This is critical for preventing ongoing transmission and reinfection.
Special Populations
Pregnancy: Ciprofloxacin is contraindicated. Azithromycin safety not established for pregnant/lactating women. No adverse fetal effects reported from chancroid itself 1, 2.