Does a patient with a history of treated syphilis, syphilis antibody reactive, Rapid Plasma Reagin (RPR) nonreactive, and Treponema Pallidum Particle Agglutination (TPPA) reactive results have active syphilis?

Does This Patient Have Active Syphilis?

No, this patient does not have active syphilis—this serologic pattern (reactive treponemal test with nonreactive RPR) represents a "serologic scar" from previously treated infection. 1, 2

Understanding This Serologic Pattern

• The combination of reactive TPPA with nonreactive RPR is the expected result following successful treatment of syphilis. This pattern indicates past infection that has been adequately treated, not active disease. 1, 2

• Treponemal tests like TPPA remain positive for life in most patients (75-85%) regardless of treatment success or disease activity, making them unsuitable for distinguishing active from past infection. 1

• In patients with previously treated syphilis, the RPR has very poor sensitivity (only 30.7-56.9%) compared to 100% sensitivity in active "infective syphilis," which explains why the RPR is now nonreactive. 3, 4

Clinical Decision Algorithm

Active syphilis is ruled out if ALL of the following criteria are met: 2

• No clinical signs or symptoms of syphilis (no chancre, rash, mucocutaneous lesions, neurologic symptoms, or ocular symptoms)
• No fourfold or greater increase in RPR titer from previous baseline
• No new sexual exposure to a partner with confirmed syphilis
• No documented seroconversion or new reactive treponemal test within the past 12 months

Red Flags That Would Change This Assessment

Reassess for active infection if any of these are present: 1, 4

• New clinical manifestations: chancre, rash, mucocutaneous lesions, adenopathy
• Neurologic symptoms: headache, vision changes, hearing loss, confusion
• Ocular symptoms: uveitis, visual disturbances
• Cardiovascular symptoms suggesting tertiary syphilis
• Documented fourfold increase in RPR titer (e.g., from nonreactive to 1:4 or higher)

Critical Pitfall to Avoid

• Never assume a reactive treponemal test alone indicates active infection. The TPPA remains positive for life in most treated patients and cannot distinguish between active disease and successfully treated past infection. 1, 4

• A nonreactive RPR in someone with treated syphilis does NOT rule out late complications. While unlikely in this asymptomatic patient with documented treatment history, RPR sensitivity drops to only 47-64% in tertiary syphilis and 61-75% in late latent disease. 4 However, given the documented treatment history and absence of symptoms, this is not a concern here.

No Further Action Required

• No treatment is indicated for this patient, as the serologic pattern confirms past treated infection without evidence of active disease. 1, 2

• Routine follow-up testing is not necessary in asymptomatic patients with this serologic pattern and documented adequate prior treatment. 1