Due to Treponema pallidum – enters through abrasion during sexual intercourse. Incubation of 14-28 days. May be complicated by HIV.
• Primary – painless hard ulcer (chancre) at site if sexual contact
• Secondary – 4-8 weeks after appearance of chancre fever, malaise, rash (trunk, palms, soles), lymphadenopathy, alopecia
• tertiary – 2-20 years after latent period; develop granuloma’s in skin, mucosa, bones and joints
• quaternary – neurosyphilis. tabes dorsalis, sensory ataxia, Charcot’s joints, general paresis of insane, dementia, cranial nerve palsies