Syphilis.

Inoculation of Treponema pallidum during intimate physical contact is followed by development of a papule that rapidly erodes, yielding the syphilitic chancre. Hematogenous dissemination results in secondary syphilis, a multisystem disease characterized by skin rash, lymph node enlargement, hepatitis, arthritis, and central nervous system involvement. In the absence of treatment, a latent period is reached after which tertiary syphilis may appear in an increasing proportion of patients, depending upon the duration of the follow-up.