Syphilis is a complex sexually transmitted disease that has a highly variable clinical course. Classification by a clinician with expertise in syphilis may take precedence over the following case definition developed for surveillance purposes.

CLINICAL DESCRIPTION

A stage of infection with Treponema pallidum characterized by one or more painless chancres (ulcers); chancres might differ considerably in clinical appearance.

  CASE CLASSIFICATION

1. CONFIRMED

   A clinically compatible case that is laboratory confirmed by:

   • Demonstration of T. pallidum in clinical specimens by darkfield microscopy, direct fluorescent antibody (DFA-TP), or equivalent methods.

2. PROBABLE
   

   • A clinically compatible case with one or more ulcers (chancres) consistent with primary syphilis and a reactive serologic test (nontreponemal: Venereal Disease Research Laboratory [VDRL] or rapid plasma reagin [RPR]; treponmenal: fluorescent treponemal antibody absorbed [FTA-ABS] or microhemagglutination assay for antibody to T. pallidum [MHA-TP]).

3. POSSIBLE
   
   

   • Not used