| Stage | Clinical manifestations | Diagnosis (sensitivity) | Treatment |
|---|---|---|---|
| Primary syphilis | Chancre | Dark-field microscopy of skin lesion (80%) Nontreponemal tests (78% to 86%) Treponemal-specific tests (76% to 84%) | Penicillin G benzathine, 2.4 million units IM (single dose) Alternatives in nonpregnant patients with penicillin allergy: doxycycline (Vibramycin), 100 mg orally twice daily for 2 weeks; tetracycline, 500 mg orally four times daily for 2 weeks; ceftriaxone (Rocephin), 1 g once daily IM or IV for 8 to 10 days; or azithromycin (Zithromax), 2 g orally (single dose) |
| Secondary syphilis | Skin and mucous membranes: diffuse rash, condyloma latum, other lesions Renal system: glomerulonephritis, nephrotic syndrome Liver: hepatitis Central nervous system: headache, meningismus, cranial neuropathy, iritis and uveitis Constitutional symptoms: fever, malaise, generalized lymphadenopathy, arthralgias, weight loss, others | Dark-field microscopy of skin lesion (80%) Nontreponemal tests (100%) Treponemal-specific tests (100%) | Same treatments as for primary syphilis |
| Latent syphilis | None | Nontreponemal tests (95% to 100%) Treponemal-specific tests (97% to 100%) | Early latent syphilis: same treatments as for primary and secondary syphilis Late latent syphilis: penicillin G benzathine, 2.4 million units IM once weekly for 3 weeks Alternatives in nonpregnant patients with penicillin allergy: doxycycline, 100 mg orally twice daily for 4 weeks; or tetracycline, 500 mg orally four times daily for 4 weeks |
| Tertiary (late) syphilis | Gummatous disease, cardiovascular disease | Nontreponemal tests (71% to 73%) Treponemal-specific tests (94% to 96%) | Same treatment as for late latent syphilis |
| Neurosyphilis | Seizures, ataxia, aphasia, paresis, hyperreflexia, personality changes, cognitive disturbance, visual changes, hearing loss, neuropathy, loss of bowel or bladder function, others | Cerebrospinal fluid examination | Aqueous crystalline penicillin G, 3 to 4 million units IV every 4 hours for 10 to 14 days; or penicillin G procaine, 2.4 million units IM once daily, plus probenecid, 500 mg orally four times daily, with both drugs given for 10 to 14 days |