A 35-year-old patient with secondary syphilis (maculopapular rash on palms and soles, mucous patches) has VDRL positive at 1:32, TPHA positive. He is allergic to penicillin. What is the appropriate alternative treatment?
- A Doxycycline 100 mg BD for 14 days is the recommended alternative for penicillin-allergic non-pregnant adults with secondary syphilis ✓
- B Tetracycline 500 mg QID for 14 days is an acceptable alternative for non-pregnant adults allergic to penicillin
- C Azithromycin 2 g single dose (WHO regimen for STIs) adequately treats secondary syphilis
- D Ceftriaxone 1 g IM daily for 14 days is always adequate as penicillin cross-allergy with cephalosporins is invariable
Explanation
Secondary syphilis (caused by Treponema pallidum) is treated with benzathine penicillin G 2.4 million units IM single dose as first-line. For penicillin-allergic non-pregnant adults, doxycycline 100 mg BD for 14 days is the WHO- and CDC-recommended alternative; tetracycline 500 mg QID for 14 days is equivalent. Azithromycin 2 g single dose has been used but macrolide-resistant T. pallidum strains (23S rRNA mutation) are increasingly prevalent globally, limiting its reliability. Ceftriaxone may be used (1 g IM/IV daily for 10–14 days) but cross-reactivity risk should be assessed; it is not universally preferred over doxycycline.
Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.