Relapse of early syphilis on first line treatment.

We describe a case of a heterosexual HIV-negative man treated for primary syphilis with oral doxycycline in accordance with Clinical Effectiveness Group guidelines for treatment of early syphilis. Following an initial adequate response, he developed secondary syphilis three months later. We discuss the most likely cause of this relapse and the significance of such cases in the context of an outbreak of syphilis.