A 28-year-old man from Mumbai presents with a painless indurated ulcer on the glans penis for 3 weeks. He also has bilateral inguinal lymphadenopathy. Serological testing shows positive RPR (1:32) and positive FTA-ABS. He denies any prior treatment for syphilis. What is the most appropriate next step in management?

Explanation

## Clinical Assessment This patient presents with classic features of **primary syphilis**: a painless, indurated ulcer (chancre) with regional lymphadenopathy and confirmed serological positivity (both non-treponemal and treponemal tests positive). ## Diagnosis Already Established **Key Point:** The diagnosis of syphilis is already confirmed by: - Clinical presentation (painless chancre + regional lymphadenopathy) - Positive RPR (non-treponemal test) - Positive FTA-ABS (treponemal test) No further diagnostic workup is needed before initiating treatment. ## Management of Primary Syphilis **High-Yield:** The standard first-line treatment for primary, secondary, and early latent syphilis (<1 year duration) is: - **Benzathine penicillin G 2.4 million units IM as a single dose** This is the WHO-recommended and CDC-recommended regimen for non-pregnant patients without penicillin allergy. ## Neurosyphilis Screening **Clinical Pearl:** Routine CSF examination (lumbar puncture) is NOT indicated in early syphilis unless: - Clinical signs/symptoms of neurosyphilis are present (meningitis, cranial nerve palsies, etc.) - The patient is HIV-positive - Tertiary syphilis is suspected This patient has no neurological symptoms, so LP is not warranted at this stage. ## Why Darkfield Microscopy Is Not Needed **Key Point:** Darkfield microscopy is a diagnostic tool used when serological tests are unavailable or in early primary syphilis with negative serology. Since this patient already has confirmed positive serology, darkfield examination adds no value and delays treatment. ## Treatment Considerations | Feature | Benzathine PCN G | Doxycycline | Ceftriaxone | |---------|------------------|-------------|-------------| | **Indication** | First-line (all stages) | Allergy to PCN, non-pregnant | PCN allergy, pregnancy | | **Efficacy** | >95% | Good for early syphilis | Good alternative | | **Duration** | Single dose | 14 days | 10–14 days | | **Neurosyphilis coverage** | Excellent | Poor | Moderate | **Warning:** Doxycycline is NOT first-line and is reserved for penicillin-allergic patients without neurosyphilis.