Syphilis
Syphilis is a systemic infection with the spirochaete Treponema pallidum that progresses through distinct, mechanistically linked stages: a localised primary chancre, disseminated secondary disease, silent latency, and destructive tertiary disease, each caused by the same organism behaving differently over time.
In a nutshell
Treponema pallidum causes a staged disease: a painless local chancre (primary), haematogenous dissemination with a multisystem rash (secondary), silent immune-controlled persistence (latent), and delayed immune-mediated destruction of skin, cardiovascular and neurological tissue (tertiary). Each stage reflects the organism's changing relationship with the host immune response, and penicillin remains the treatment of choice throughout.
Classic presentation
A painless genital ulcer with non-tender regional lymphadenopathy (primary), or a widespread rash involving the palms and soles with lymphadenopathy some weeks later (secondary).
Key points
- The chancre of primary syphilis is classically painless: immune evasion, not low virulence, is what allows it to resolve spontaneously while the organism persists.
Educational content pending clinical review. Not medical advice.