American Urological Association - Syphilis
- Agent: Treponema pallidum - "the great mimicker".
- Appearance: gram-negative spirochete.
- Clinical: 3 stages:
- Primary: papule on the penis → ulcerated painless chancre; resolves without treatment in 6-8 weeks (image A).
- Secondary: maculopapular, annular, or hyperpigmented lesions, especially on palms and soles.
- Tertiary: granulomas (gummas) that may involve the CNS.
- Primary: dark-field microscopy or special stain reveals spirochetes (image B); lymphoplasmacytic vasculitis; antibody test is negative.
- Secondary: organisms may or may not be seen; lymphoplasmacytic inflammation; antibody test is positive.
- Tertiary: small compact granulomas that eventually caseate.
- Treatment: antibiotics.