Secondary syphilis: Hepatitis, rashes and prozone phenomenon

Syphilis is a sexually transmitted disease. Sometimes, it is challenging to diagnose due to false negative serologic results. Therefore, the proper use and interpretation of diagnostic testing are important for optimal patient management. Prozone phenomenon is a very rare and false negative reaction and occurs due to disproportionately increased antibodies in a specimen. Immune system is responsible for excess antibodies. It is frequently seen in HIV, neurosyphilis, early syphilis (mainly secondary syphilis). This reaction causes delays in the diagnosis and treatment of the disease. Thus, in cases where VDRL is non-reactive, it is important for clinicians to consider prozone reaction in patients with clinical signs suggesting syphilis. Here, we present a case of secondary syphilis diagnosed late due to prozone phenomenon.