What tests are recommended for ulceration on the scrotum?

Diagnostic Testing for Scrotal Ulceration

For scrotal ulcerations, a comprehensive diagnostic approach should include serologic testing for syphilis, nucleic acid amplification testing (NAAT) or culture for herpes simplex virus (HSV), and culture for Haemophilus ducreyi, as these are the most common infectious causes of genital ulcers. 1

Primary Diagnostic Tests

• Serologic test for syphilis - this should be performed for all patients with genital ulcers as a baseline test 1
• NAAT/PCR for HSV (preferred) or HSV culture - to detect herpes simplex virus, which is the most common cause of genital ulcers in the United States 1, 2
• Darkfield examination or direct immunofluorescence test for Treponema pallidum - to directly visualize the causative organism of syphilis 1
• Culture for Haemophilus ducreyi - particularly in areas where chancroid is prevalent 1
• HIV testing - should be performed for patients with confirmed syphilis or chancroid, and considered for those with HSV 1

Testing Considerations

HSV Testing

• NAAT/PCR tests are highly sensitive (>90%) and specific for HSV and are preferred over culture 1
• Tests that differentiate between HSV-1 and HSV-2 should be used to provide information about expected natural history 1
• HSV culture is less sensitive than NAAT but is reasonable if NAAT is unavailable 1
• Direct immunofluorescence assay and Tzanck smear lack sensitivity and are not recommended 1

Syphilis Testing

• Serologic testing should be performed at initial presentation 1
• If initial test is negative but clinical suspicion remains high, repeat testing should be performed at least 7 days after onset of ulcers 1

Chancroid Testing

• Culture for H. ducreyi requires special media not widely available commercially 1
• A probable diagnosis may be made based on clinical presentation when a painful ulcer is present, syphilis testing is negative, and HSV testing is negative 1

Additional Testing Based on Clinical Presentation

• Ultrasound imaging - should be considered when there is scrotal swelling, pain, or suspected underlying pathology beyond the ulceration 3, 4, 5
• For traumatic causes of scrotal lesions, ultrasound with color Doppler can assess testicular perfusion and identify hematomas 4

Management Approach When Test Results Are Pending

• Treat empirically for the diagnosis considered most likely based on clinical presentation 1
• If diagnosis is unclear, many experts recommend treatment for syphilis, or for both syphilis and chancroid if in a community where chancroid is prevalent 1
• Be aware that even after complete diagnostic evaluation, approximately 25% of patients with genital ulcers have no laboratory-confirmed diagnosis 1

Pitfalls to Avoid

• Relying solely on clinical appearance for diagnosis - this is often inaccurate 1
• Failing to consider non-infectious causes such as trauma, psoriasis, Behçet syndrome, and fixed drug eruptions 2
• Delaying testing in cases of suspected testicular torsion, which requires immediate surgical intervention 6
• Not testing for HIV in patients with confirmed sexually transmitted genital ulcers 1

Remember that prompt diagnosis and treatment are essential, particularly for conditions like testicular torsion or Fournier's gangrene that require urgent surgical intervention 5, 6.