A 32-year-old woman from Delhi presents with a 2-month history of a maculopapular rash involving the trunk and extremities, including the palms and soles. She also reports fever, generalized lymphadenopathy, and condylomata lata in the perianal region. She denies any genital ulcer. Serological testing shows RPR titre 1:64 and positive FTA-ABS. She is 8 weeks pregnant. What is the most appropriate next step in management?

Explanation

## Management of Secondary Syphilis in Pregnancy ### Diagnosis: Secondary Syphilis **Key Point:** The clinical presentation—maculopapular rash (including palms and soles), fever, generalized lymphadenopathy, and condylomata lata—combined with **high RPR titre (1:64) and positive FTA-ABS** is diagnostic of secondary syphilis. ### Why Benzathine Penicillin G Is the Answer **High-Yield:** Penicillin is the **only drug with proven efficacy in preventing congenital syphilis** and treating maternal syphilis in pregnancy. It crosses the placenta and reaches fetal tissues in bactericidal concentrations. **Clinical Pearl:** In pregnancy, the regimen is **benzathine penicillin G 2.4 million units IM weekly × 3 weeks** (total 7.2 million units). This is the **only regimen recommended by CDC, WHO, and Indian guidelines** for syphilis in pregnancy. ### Dosing Regimen by Stage | Stage | Non-Pregnant | Pregnant | Rationale | |-------|--------------|----------|----------| | **Primary/Secondary** | 2.4 MU IM once | 2.4 MU IM weekly × 3 | Sustained levels for fetal penetration | | **Tertiary/Neurosyphilis** | 2.4 MU IM weekly × 3 | 2.4 MU IM weekly × 3 | Same in both | | **Penicillin allergy (non-pregnant)** | Doxycycline or ceftriaxone | Ceftriaxone only (if allergy not anaphylaxis) | Doxycycline is teratogenic | **Mnemonic: PENICILLIN IN PREGNANCY** — **P**enicillin is **E**ssential, **N**o **I**nterchange, **C**rossing **I**s **L**ife-saving, **L**arge doses, **I**nterval weekly, **N**ever substitute. ### Why Other Options Are Wrong **Warning:** Tetracyclines (doxycycline) are **absolutely contraindicated in pregnancy** because they: - Cause permanent yellow discoloration of fetal teeth - Inhibit bone growth - Are teratogenic in the first trimester **Erythromycin** and **ceftriaxone** are not first-line for maternal syphilis because: - **Erythromycin**: Poor placental penetration; does not reliably prevent congenital syphilis; treatment failure rates up to 10–15% - **Ceftriaxone**: Not standard for maternal syphilis; reserved for penicillin-allergic patients (non-anaphylaxis) when penicillin desensitization is not feasible ### Congenital Syphilis Prevention **Key Point:** Maternal treatment with penicillin reduces the risk of congenital syphilis from ~100% (untreated) to <2% if given before 16 weeks gestation, and <5% if given after 16 weeks. ### Follow-Up 1. **Serological follow-up**: RPR at 3, 6, 12 months (should decline 4-fold by 12 months) 2. **Neonatal screening**: Cord blood serology and clinical examination 3. **Partner notification and treatment**: Essential to prevent reinfection 4. **Jarisch-Herxheimer reaction**: May occur within 24 hours of first dose; manage with antipyretics and hydration [cite:CDC STI Guidelines 2021; Park 26e Ch 25]