What is the treatment for a patient with a penile ulcer and a positive Venereal Disease Research Laboratory (VDRL) test?

Treatment of Penile Ulcer with Positive VDRL

Treat immediately with benzathine penicillin G 2.4 million units intramuscularly as a single dose for presumed primary syphilis. 1, 2

Immediate Management

• Administer benzathine penicillin G 2.4 million units IM in a single dose - this is the CDC-recommended treatment for primary syphilis presenting with a chancre (penile ulcer) and positive VDRL. 1, 2

• Before treating, assess for neurologic symptoms (headache, confusion, vision or hearing changes), as neurosyphilis requires IV penicillin therapy instead of IM benzathine penicillin. 2

• Obtain a quantitative VDRL or RPR titer (not just positive/negative) to establish a baseline for monitoring treatment response. 1, 3

Diagnostic Confirmation

• Perform darkfield microscopy or direct fluorescent antibody testing on the ulcer exudate - this is the gold standard for diagnosing primary syphilis and confirms active infection. 3, 2

• The VDRL sensitivity in primary syphilis is only 62-78%, meaning some early primary cases can be seronegative, but your patient is already VDRL-positive. 4

• Consider testing for HIV infection at the time of diagnosis, as HIV coinfection is common and may require modified monitoring. 4, 1

Differential Diagnosis Considerations

• While treating for syphilis, remain aware that 10% of patients with chancroid may be coinfected with T. pallidum, and genital ulcer disease can have multiple etiologies. 4

• If the clinical presentation is atypical or the patient resides in an area with notable chancroid prevalence, consider empiric treatment for both syphilis and chancroid (azithromycin 1g PO single dose or ceftriaxone 250mg IM single dose for chancroid coverage). 4

Follow-Up and Monitoring

• Repeat quantitative nontreponemal testing (VDRL or RPR) at 6 and 12 months after treatment to confirm treatment response. 1, 2

• A fourfold decline in titer (two dilutions, e.g., from 1:32 to 1:8) indicates successful treatment. 1, 2

• If no fourfold decline occurs by 6-12 months, or if clinical symptoms persist or recur, suspect treatment failure or reinfection. 1

• Use the same test type (VDRL or RPR) and preferably the same laboratory for all follow-up testing, as results are not directly comparable between different test methods. 1, 3

Special Populations

• For HIV-infected patients: Use the same treatment regimen but monitor more frequently (at 3-month intervals instead of 6-month intervals), as they may have atypical serologic responses with unusually high, low, or fluctuating titers. 1

• For penicillin-allergic patients: Doxycycline 100mg orally twice daily for 14 days is an alternative for early syphilis, though penicillin desensitization is preferred if compliance cannot be ensured. 1, 2

Critical Pitfalls to Avoid

• Do not delay treatment waiting for darkfield microscopy results - treat based on clinical presentation and positive VDRL. 4, 2

• Do not use treponemal tests (FTA-ABS, TP-PA) to monitor treatment response, as these remain positive for life regardless of cure. 1, 3

• Do not assume a low VDRL titer means mild disease - titers can be low in early primary syphilis, and direct organism detection supersedes titer interpretation. 2

• Evaluate and treat all sexual contacts from the past 3 months for primary syphilis. 1