Syphilis in adults: updates on testing, prevention and treatment

Syphilis has re-emerged as a significant public health concern in Australia, with rising notification rates among both traditional and non-traditional risk groups. Declared a Communicable Disease Incident of National Significance, syphilis continues to pose a diagnostic challenge due to its myriad of different presentations and ability to mimic other diseases. The recent rise in cases of congenital syphilis is particularly concerning and highlights the urgent need for improvement in syphilis testing in antenatal care. This clinical perspective provides a contemporary and relevant summary of the evolving epidemiology, staging of syphilis infections, interpretation of serological tests, as well as management approaches including partner notification and follow-up testing. We also outline advances in syphilis diagnostics-including nucleic acid amplification tests and point-of-care tests-which have made it much easier to detect syphilis infections early. The recent availability of doxycycline as post-exposure prophylaxis is also discussed, which offers a promising tool to prevent infections and re-infections in at-risk populations, namely men who have sex with men and transgender women. Treatment for syphilis continues to rely primarily on long-acting injectable benzathine benzylpenicillin, with alternative regimens being used increasingly amid a continual global shortage of this formulation of penicillin. Encouragingly, there are early signs that suggest notification rates for syphilis are finally decreasing in some jurisdictions, likely in response to the multitude of interventions implemented as part of the national syphilis response. Physicians in all specialties should remain aware and confident in testing and managing syphilis in order to continue cementing this downward trend.