CDC Guidelines for Syphilis Management

Staging Definitions

• Early latent syphilis is defined as infection acquired within the preceding year. [**CDC**] [1]
• Late latent syphilis is defined as infection acquired more than one year ago or of unknown duration. [**CDC**] [2]
• Individuals are infectious during the early latent stage, but transmissibility is markedly reduced in late latent infection. [**CDC**] [1]

Diagnostic Recommendations

• When serologic tests are non‑reactive but clinical suspicion remains, alternative direct‑detection methods (e.g., lesion biopsy, dark‑field microscopy, DFA staining) should be employed. [**CDC**] [2]
• Routine cerebrospinal fluid (CSF) examination is not indicated for primary or secondary syphilis unless neurologic or ophthalmic manifestations are present. [**CDC**] [3]
• CSF examination is required before treatment of HIV‑infected patients with late latent syphilis or syphilis of unknown duration. [**CDC**] [2]
• CSF should be obtained when treatment failure is suspected. [**CDC**] [3]

Treatment Recommendations

• For primary and secondary syphilis in HIV‑infected persons, some experts advise three weekly doses of benzathine penicillin G 2.4 million U IM (instead of a single dose). [**CDC**] [2]
• In penicillin‑allergic, non‑pregnant patients, doxycycline 100 mg PO twice daily for 14 days is recommended; an alternative tetracycline regimen (500 mg PO four times daily for 14 days) may be used, though adherence is generally lower. [**CDC**] [3]
• Ceftriaxone 1 g IM or IV daily for 8–10 days can be considered for penicillin‑allergic patients, but optimal dosing remains undefined. [**CDC**] [3]
• Close clinical follow‑up is essential when alternative regimens are used because efficacy data are less robust. [**CDC**] [3]
• HIV‑infected patients with late latent syphilis should undergo CSF examination before initiating therapy. [**CDC**] [2]
• Neurosyphilis should be included in the differential diagnosis of neurologic disease in HIV‑infected individuals. [**CDC**] [2]
• HIV‑infected patients receive the same antimicrobial regimens as HIV‑negative patients, although some clinicians recommend enhanced therapy. [**CDC**] [2]
• Follow‑up intervals for HIV‑infected patients should be every 3 months rather than every 6 months. [**CDC**] [2]
• HIV‑infected individuals are at higher risk for neurologic complications and treatment failure. [**CDC**] [2]

Follow‑Up and Monitoring

• Quantitative non‑treponemal tests (e.g., RPR) should be repeated at 6 months and 12 months after treatment of primary or secondary syphilis, with an expected ≥4‑fold decline by 6 months. [**CDC**] [3]
• For HIV‑infected patients, serologic testing should be performed at 3, 6, 9, 12, and 24 months post‑treatment. [**CDC**] [2]

Treatment Failure Criteria

• Persistent or recurrent clinical signs/symptoms. [**CDC**] [3]
• A sustained ≥4‑fold increase in non‑treponemal titer. [**CDC**] [3]
• Failure of the non‑treponemal titer to decline ≥4‑fold within 6 months after therapy for primary or secondary disease. [**CDC**] [3]

Management of Treatment Failure

• Patients meeting failure criteria should undergo CSF examination and receive re‑treatment. [**CDC**] [3]
• Re‑treatment regimen: benzathine penicillin G 2.4 million U IM weekly for 3 weeks (unless CSF indicates neurosyphilis). [**CDC**] [3]
• HIV‑infected patients whose titers do not decrease ≥4‑fold within 6–12 months should have CSF examination and be re‑treated accordingly. [**CDC**] [2]

Partner Management

• For primary syphilis, partners exposed within the preceding 3 months plus the duration of symptoms should be identified; for secondary syphilis, the window extends to 6 months plus symptom duration; for early latent syphilis, partners up to 1 year before diagnosis should be traced. [**CDC**] [1]
• Partners exposed more than 90 days before the index case’s diagnosis should receive presumptive treatment if serologic results are unavailable or follow‑up is uncertain; otherwise, treatment is based on serologic testing. [**CDC**] [1]

Special Considerations

Jarisch‑Herxheimer Reaction

• An acute febrile reaction with headache, myalgia, and other systemic symptoms may occur within 24 hours of any syphilis therapy. [**CDC**] [1]
• Patients should be counseled about this reaction before treatment; antipyretics may provide symptomatic relief, but no proven prophylactic measures exist. [**CDC**] [1]
• In pregnant individuals, the reaction can precipitate early labor or fetal distress, but therapy should not be delayed. [**CDC**] [1]

HIV Co‑infection

• All persons diagnosed with syphilis should be screened for HIV because co‑infection is common and influences management and follow‑up. [**CDC**] [2]
• HIV‑infected patients may exhibit atypical serologic patterns (elevated titers, false‑negative results, delayed seroreactivity). [**CDC**] [2]

CSF Invasion

• Treponema pallidum frequently invades the CSF during primary and secondary stages, yet overt neurosyphilis develops in only a minority after standard therapy. [**CDC**] [3]

Penicillin Allergy

• Penicillin remains the sole proven effective therapy for neurosyphilis and syphilis during pregnancy; patients with allergy must undergo desensitization. [**CDC**] [1]
• Skin testing for penicillin allergy may be useful, although minor determinant reagents are not commercially available. [**CDC**] [1]

Syphilis Diagnosis and Treatment

Clinical Manifestations

• The Centers for Disease Control and Prevention recommends that primary syphilis is characterized by a painless ulcer or chancre at the site of infection, typically accompanied by regional lymphadenopathy 4
• The American College of Physicians notes that multiple or atypical chancres may occur in HIV-infected individuals, and primary lesions might be absent or missed 4
• The Centers for Disease Control and Prevention states that secondary syphilis can mimic acute primary HIV infection with constitutional symptoms and CSF abnormalities 4
• The MMWR Recommendations and Reports guideline suggests that latent syphilis is characterized by positive serologic tests without clinical manifestations 4, 5
• The Centers for Disease Control and Prevention recommends that tertiary syphilis occurs in approximately 25% of untreated patients after 3-12 years of latency, with manifestations including gummatous lesions, cardiovascular syphilis, and neurologic involvement 4, 6, 7

Diagnosis

• The MMWR Recommendations and Reports guideline recommends that darkfield examination and direct fluorescent antibody tests of lesion exudate or tissue are definitive methods for diagnosing early syphilis 6, 8
• The Centers for Disease Control and Prevention suggests that serologic testing involves two types of tests: nontreponemal tests (VDRL, RPR) and treponemal tests (FTA-ABS, MHA-TP) 6, 8
• The MMWR Recommendations and Reports guideline notes that a fourfold change in nontreponemal test titer is considered clinically significant 6, 8

Treatment

• The Centers for Disease Control and Prevention recommends that the treatment regimen for primary and secondary syphilis is Benzathine penicillin G 2.4 million units IM in a single dose 9, 5
• The MMWR Recommendations and Reports guideline suggests that the treatment regimen for late latent syphilis or latent syphilis of unknown duration is Benzathine penicillin G 7.2 million units total, administered as three doses of 2.4 million units IM at 1-week intervals 7, 5
• The Centers for Disease Control and Prevention recommends that the treatment regimen for neurosyphilis is Aqueous crystalline penicillin G 18-24 million units a day, administered as 3-4 million units IV every 4 hours for 10-14 days 7, 5

Special Considerations

• The MMWR Recommendations and Reports guideline notes that HIV-infected patients may have more apparent clinical lesions and accelerated progression of syphilitic disease 4
• The Centers for Disease Control and Prevention recommends that all patients with syphilis should be tested for HIV 9
• The MMWR Recommendations and Reports guideline suggests that pregnant women should be treated with penicillin regimens appropriate for their stage of syphilis 5

Follow-Up

• The MMWR Recommendations and Reports guideline recommends that quantitative nontreponemal tests should be repeated at regular intervals (3, 6, 12, and 24 months) 5
• The Centers for Disease Control and Prevention suggests that a fourfold decline in titer is expected within 6 months for primary/secondary syphilis 5
• The MMWR Recommendations and Reports guideline notes that treatment failure is defined as failure of nontreponemal test titers to decline fourfold within 6 months after therapy for primary or secondary syphilis 5

Syphilis Treatment Guidelines

Antibiotic Treatment

• The Centers for Disease Control and Prevention recommends alternative regimens, including doxycycline 100 mg orally twice daily for 14 days, for patients allergic to penicillin 10

Syphilis Treatment and Management

Treatment Guidelines

• The Centers for Disease Control and Prevention recommends that penicillin-allergic patients with late syphilis be treated with doxycycline 100 mg orally twice daily for 28 days 11
• The Centers for Disease Control and Prevention suggests that pregnant women and patients with neurosyphilis who are penicillin-allergic must be desensitized and treated with penicillin, as it is the only effective option 12
• The Centers for Disease Control and Prevention recommends that patients with neurosyphilis be treated with aqueous crystalline penicillin G 18-24 million units per day IV for 10-14 days, although the citation for this fact is not provided, an alternative source states that penicillin-allergic patients with early syphilis can be treated with doxycycline 100 mg orally twice daily for 14 days 11

Clinical Considerations

• The Centers for Disease Control and Prevention notes that the Jarisch-Herxheimer reaction, an acute febrile reaction with headache and myalgia, may occur within 24 hours after any therapy for syphilis 13
• The Centers for Disease Control and Prevention recommends that all patients with syphilis should be tested for HIV, although the citation for this fact is not provided, it is a crucial consideration in clinical management 12

Complications of Untreated Syphilis

Neurologic Complications

• Neurologic manifestations of neurosyphilis can include auditory disease, cranial nerve dysfunction, acute or chronic meningitis, stroke, altered mental status, and loss of vibration sense. 14, 15, 16, 17
• Ophthalmic complications such as iritis and uveitis may result in permanent vision loss. 14

Cardiovascular Complications

• Active tertiary syphilis can present with aortitis and gumma formation, reflecting obliterative endarteritis of the vasa vasorum that predisposes to aortic aneurysm, aortic regurgitation, and coronary ostial stenosis. 14, 15, 16, 17

Latent Disease Progression

• Treating latent syphilis aims to prevent progression to tertiary complications because the infection remains active even without symptoms. 14, 15, 16, 17
• Nontreponemal serologic titers are generally higher during early latent syphilis (infection ≤ 1 year) than during late latent infection (infection > 1 year or unknown duration). 14, 15, 16