Syphilis (Treponema pallidum) 2026 Case Definition

NOTE: A surveillance case definition is a set of uniform criteria used to define a disease for public health surveillance. Surveillance case definitions enable public health officials to classify and count cases consistently across reporting jurisdictions. Surveillance case definitions are not intended to be used by healthcare providers for making a clinical diagnosis or determining how to meet an individual patient’s health needs.

CSTE Position Statement(s)

25-ID-08

Subtype(s)

Syphilis, primary
Syphilis, secondary
Syphilis, early non-primary non-secondary
Syphilis, unknown duration or late
Syphilis, congenital

Background

Acquired syphilis is a sexually transmitted infection (STI) caused by the bacterium Treponema pallidum that typically progresses through multiple stages, alternating between symptomatic periods and periods of latency when no signs or symptoms of infection are present. T. pallidum is most commonly transmitted from person to person during vaginal, anal, or oral sex through direct contact with syphilitic lesions that occur during the primary (e.g., chancres) or secondary (e.g., condylomata lata, mucous patches) stages of infection. Although transmission typically occurs from persons with syphilitic lesions, many of these lesions are undetected. Thus, transmission may occur from persons who are unaware of their infection. Further, if untreated or inadequately treated, persons who are infected are at risk for severe sequelae, such as neurologic, ocular, and otic manifestations, at any stage of syphilitic infection. Those who remain untreated or inadequately treated may even develop late clinical manifestations (i.e., tertiary syphilis) 10 to 30 years after infection.

During pregnancy, T. pallidum can be transmitted across the placenta to the fetus at any stage of syphilitic infection and cause congenital syphilis. Likewise, during vaginal delivery, T. pallidum can be transmitted to the infant through direct contact with syphilitic lesions. Syphilis exposure to a fetus during pregnancy or an infant during vaginal delivery can lead to a wide variety of outcomes. Severe pregnancy complications may include miscarriage, stillbirth, or preterm delivery; while no clinical signs or symptoms may be apparent in an infant at birth, negative health effects in infants may occur, including perinatal death or multiple clinical manifestations. Even with adequate treatment, infants with congenital syphilis may experience lifelong physical and neurologic effects due to their infection.

Clinical and surveillance approaches and goals are different for the identification and staging of syphilis. The goal of clinical staging of syphilis is to ensure that a patient receives appropriate stage-specific treatment. The clinical approach typically focuses on identifying and treating all likely cases of syphilis using the information available at the time of clinical care. For this reason, clinicians apply criteria that have a high level of sensitivity, meaning that there are few false-negative results and thus fewer infections are missed.

Conversely, the goal of syphilis surveillance staging is to consistently monitor the burden of disease and identify cases for disease intervention. Surveillance staff typically leverage all available information captured over time (i.e., health department record searches, patient interviews by public health staff, and provider reports) to ensure that surveillance staging is accurate. Surveillance case definitions for acquired syphilis tend to be more specific (i.e., narrow) than clinical acquired syphilis staging determinations, thus generating fewer false positive results and improving accurate case ascertainment. By contrast, because congenital syphilis represents a failure of both the healthcare and the public health systems, it is important to capture as many cases as possible. Therefore, the surveillance case definition for congenital syphilis aims to maximize sensitivity. While clinical and surveillance staging are the same most of the time, they may not always align. It is important to remember that surveillance case definitions are not intended to be used by healthcare providers for making a clinical diagnosis or determining how to meet an individual patient’s health or treatment needs.

Syphilis has been a nationally notifiable condition since 1944. The burden of syphilis has been high in recent years with over 200,000 cases of total syphilis reported in the United States for 2023, including more than 3,800 cases of congenital syphilis. Additionally, severe complications of acquired syphilis, including neurologic, ocular, and otic manifestations, continue to occur, often following trends in acquired syphilis.

Subtype(s) Case Definition

Background

A stage of infection with T. pallidum that reflects systemic dissemination and is characterized by a wide variety of signs or symptoms.

Clinical Criteria

In the absence of a more likely alternative diagnosis, meets at least one of the following signs^††‡‡:

Localized or diffuse body rash classically described as copper-colored lesions that can be any combination of macular, papular, squamous, or pustular in appearance and typically involve the chest, back, palms of the hands, and/or soles of the feet, OR
Mucous patches, OR
Condylomata lata, OR
Patchy alopecia that is often described as “moth-eaten” in appearance.

^††The primary ulcerative lesion may still be present.

^‡‡Given that syphilis is often referred to as “the great imitator”, this list is not exhaustive, and signs and symptoms may be nonspecific (e.g., secondary syphilis with visceral organ manifestations).

Laboratory Criteria

Confirmatory Laboratory Evidence:

Meets at least one of the following criteria:

Direct detection of T. pallidum by darkfield microscopy in a specimen that was both not obtained from the oropharynx and not potentially contaminated by stool, OR
Direct detection of T. pallidum by IHC staining in a specimen that was both not obtained from the oropharynx and not potentially contaminated by stool, OR
Direct detection of T. pallidum by nucleic acid amplification test (e.g., PCR, LAMP) or a diagnostically equivalent molecular method in any specimen.

Presumptive Laboratory Evidence:

A current (i.e., a test performed in the context of this index presentation) reactive blood-based nontreponemal antibody test (i.e., VDRL, RPR, point-of-care, or equivalent nontreponemal method), AND
A reactive blood-based treponemal antibody test (i.e., TP-PA, EIA, CIA, MFI or MIA, FTA-ABS, point-of-care, or equivalent treponemal method)^¶.

Supportive Laboratory Evidence:

A current (i.e., a test performed in the context of this index presentation) reactive blood-based nontreponemal antibody test (i.e., VDRL, RPR, point-of-care, or equivalent nontreponemal method) with a titer that is greater than or equal to 1:32, AND
No evidence of a concurrent nonreactive blood-based treponemal antibody test.

Note: The categorical labels used here to stratify laboratory evidence are intended to support the standardization of case classifications for public health surveillance. The categorical labels should not be used to interpret the utility or validity of any laboratory test methodology.

^¶Current or historical reactive treponemal antibody tests can be used to satisfy this criterion.

Case Classification

Probable

Meets clinical criteria AND either:
- Meets presumptive laboratory evidence, OR
- Meets supportive laboratory evidence.

Confirmed

Meets clinical criteria AND meets confirmatory laboratory evidence.

Background

A stage of infection with T. pallidum characterized by no clinical signs or symptoms of primary or secondary syphilis and evidence that the infection occurred during the previous 12 months.

Clinical Criteria

Documented history of syphilis.

Laboratory Criteria

Confirmatory Laboratory Evidence:

Direct detection of T. pallidum by nucleic acid amplification test (e.g., PCR, LAMP) or a diagnostically equivalent molecular method in any specimen.

Presumptive Laboratory Evidence:

A current (i.e., a test performed in the context of this index presentation) reactive blood-based nontreponemal antibody test (i.e., VDRL, RPR, point-of-care, or equivalent nontreponemal method), AND
A reactive blood-based treponemal antibody test (i.e., TP-PA, EIA, CIA, MFI or MIA, FTA-ABS, point-of-care, or equivalent treponemal method)^¶.

Supportive Laboratory Evidence:

A current (i.e., a test performed in the context of this index presentation) blood-based nontreponemal antibody test titer demonstrating a fourfold or greater increase,^** AND
No evidence of a concurrent nonreactive blood-based treponemal antibody test.

^¶Current or historical reactive treponemal antibody tests can be used to satisfy this criterion.

^**For surveillance purposes, the blood-based nontreponemal antibody test is not required to be repeated. However, in the absence of treatment initiation, when blood-based nontreponemal antibody testing is repeated, if the repeat specimen is collected less than or equal to 30 days after the specimen that demonstrated a fourfold increase in titers, and the repeat specimen demonstrates that the fourfold increase in titers was not sustained, the case does not meet the supportive laboratory evidence for early non-primary non-secondary syphilis.

Epidemiologic Linkage

Sexual exposure to a partner during the previous 12 months who had primary, secondary, or early non-primary non-secondary syphilis (documented independently as duration of syphilitic infection less than or equal to 12 months), OR
Only sexual contact (sexual debut) was during the previous 12 months.

Other Evidence of Infection Acquired during Previous 12 Months

Does not meet clinical criteria AND has evidence of seroconversion of a blood-based nontreponemal antibody or treponemal antibody test in a specimen that was collected during the previous 12 months, OR
Meets clinical criteria AND has evidence of a current (i.e., a test performed in the context of this index presentation) blood-based nontreponemal antibody test titer demonstrating a fourfold or greater increase in a specimen that was collected during the previous 12 months, OR
Signs or symptoms consistent with primary or secondary syphilis during the previous 12 months, OR
Greater than or equal to fourfold increase in a blood-based nontreponemal antibody test titer from a specimen that was collected between the initial specimen collection date and the treatment initiation date.

Case Classification

Probable

Does not meet clinical criteria AND meets presumptive laboratory evidence AND meets epidemiologic linkage criteria, OR
Does not meet clinical criteria AND meets presumptive laboratory evidence AND meets other evidence of infection acquired during previous 12 months, OR
Meets clinical criteria AND meets supportive laboratory evidence AND meets epidemiologic linkage criteria, OR
Meets clinical criteria AND meets supportive laboratory evidence AND meets other evidence of infection acquired during previous 12 months.

Confirmed

Meets confirmatory laboratory evidence AND meets epidemiologic linkage criteria, OR
Meets confirmatory laboratory evidence AND meets other evidence of infection acquired during previous 12 months.

Background

A stage of infection with T. pallidum characterized by no clinical signs or symptoms of primary or secondary syphilis and either the infection occurred greater than 12 months prior or there is insufficient evidence to conclude that infection was acquired during the previous 12 months.

Clinical Criteria

Documented history of syphilis.

Laboratory Criteria

Confirmatory Laboratory Evidence:

Direct detection of T. pallidum by IHC staining in a specimen that was both not obtained from the oropharynx and not potentially contaminated by stool, OR
Direct detection of T. pallidum by nucleic acid amplification test (e.g., PCR, LAMP) or a diagnostically equivalent molecular method in any specimen.

Presumptive Laboratory Evidence:

A current (i.e., a test performed in the context of this index presentation) reactive blood-based nontreponemal antibody test (i.e., VDRL, RPR, point-of-care, or equivalent nontreponemal method), AND
A reactive blood-based treponemal antibody test (i.e., TP-PA, EIA, CIA, MFI or MIA, FTA-ABS, point-of-care, or equivalent treponemal method)^¶.

Supportive Laboratory Evidence:

A current (i.e., a test performed in the context of this index presentation) blood-based nontreponemal antibody test titer demonstrating a fourfold or greater increase^§§ AND
No evidence of a concurrent nonreactive blood-based treponemal antibody test.

^¶Current or historical reactive treponemal antibody tests can be used to satisfy this criterion.

^§§For surveillance purposes, there is no requirement that the blood-based nontreponemal antibody test be repeated. However, in the absence of treatment initiation, when blood-based nontreponemal antibody testing is repeated, if the repeat specimen is collected less than or equal to 30 days after the specimen that demonstrated a fourfold increase in titers, and the repeat specimen demonstrates that the fourfold increase in titers was not sustained, the case does not meet the supportive laboratory evidence for unknown duration or late syphilis.

Case Classification

Probable

No evidence of having acquired the infection within the preceding 12 months^*** AND does not meet clinical criteria AND meets presumptive laboratory evidence, OR
No evidence of having acquired the infection within the preceding 12 months^*** AND meets clinical criteria AND meets supportive laboratory evidence, OR
Does not otherwise meet the surveillance case definition for any other stage of syphilis as described above AND no evidence of having acquired the infection within the preceding 12 months^*** AND meets the definition for likely or verified neurologic, ocular, otic, or late clinical manifestations of syphilis as described later in this position statement.

Confirmed

No evidence of having acquired the infection within the preceding 12 months^***AND meets confirmatory laboratory evidence.

^***See epidemiologic linkage criteria and other evidence of infection acquired during previous 12 months in Syphilis, early non-primary non-secondary case definition.

Background

An infection of a stillbirth, neonate, or older child with T. pallidum contracted via transplacental transmission or, more rarely, exposure to genital lesions during birth. Congenital syphilis is commonly asymptomatic but may present with early or late signs and symptoms which are often non-specific.

Clinical Criteria

A liveborn infant or child aged less than 2 years with any of the following signs or symptoms where there is not another more likely cause^*:
- Rhinitis (i.e., copious nasal secretions, “syphilitic snuffles”)
- Skin rash (e.g., maculopapular, consisting of small dark red-copper spots that is most severe on the hands and feet or vesicular rash – pemphigus syphiliticus); the skin rash can be associated with desquamation/sloughing
- Condylomata lata
- Pseudoparalysis of an extremity due to osteochondritis or periostitis
- Nonimmune hydrops or edema; nephrotic syndrome
- Conjugated or direct hyperbilirubinemia
- Cholestatic jaundice or cholestasis
- Hepatosplenomegaly
- Other nonspecific signs/symptoms such as those listed below may provide supportive clinical evidence:
  - Lymphadenopathy
  - Fever
  - Mucocutaneous lesions
  - Pneumonia/pneumonitis
  - Hemolytic anemia or thrombocytopenia during the first 8 weeks after birth
  - Another clinical sign or symptom documented by a clinician to be consistent with a diagnosis of congenital syphilis

An older child (greater than or equal to 2 years of age) with any of the following signs or symptoms where there is not another more likely cause^*:
- Interstitial keratitis
- Nerve deafness
- Anterior bowing of shins
- Frontal bossing
- Mulberry molars
- Hutchinson teeth
- Saddle nose
- Rhagades
- Clutton joints

^*Given that congenital syphilis is a multisystemic condition with varying presentations, this list is not exhaustive, and signs and symptoms of congenital syphilis may be nonspecific.

Other Fetal Death/Stillbirth Criteria

A fetal death/stillbirth that occurs either:
- at or after 20 weeks of gestation, OR
- in which the fetus weighs greater than or equal to 350 grams.

Laboratory Criteria

Confirmatory Laboratory Evidence:

Meets at least one of the following criteria in an appropriate specimen^†:

Direct detection of T. pallidum by darkfield microscopy in a specimen that was both not obtained from the oropharynx and not potentially contaminated by stool, OR
Direct detection of T. pallidum by IHC staining in a specimen that was both not obtained from the oropharynx and not potentially contaminated by stool, OR
Direct detection of T. pallidum by nucleic acid amplification test (e.g., PCR, LAMP) or a diagnostically equivalent molecular method in any specimen.

Presumptive Laboratory Evidence:

A current (i.e., a test performed in the context of this index presentation) reactive blood-based nontreponemal antibody test (i.e., VDRL, RPR, point-of-care, or equivalent nontreponemal method) collected from an infant or child.

Supportive Laboratory/Radiographic Evidence:

Meets at least one of the following criteria in an infant or child, with no other identifiable causes for these abnormalities:

In a lumbar puncture without visibly blood-contaminated cerebrospinal fluid (CSF)^‡, a reactive CSF VDRL test or an elevated CSF leukocyte^§ (white blood cell, WBC) count, OR
A blood-based nontreponemal antibody test titer at least fourfold higher than the maternal blood-based nontreponemal antibody test titer in specimens collected during the immediate postnatal period (i.e., within 7 days), OR
Evidence on radiographs of long bone abnormalities consistent with congenital syphilis.

^†An appropriate specimen is defined for each test type in the CDC Laboratory Recommendations for Syphilis Testing or equivalent guidance documents.

^‡For the purposes of the syphilis surveillance case definition, visibly blood-contaminated CSF is defined as a CSF red blood cell (RBC) count of greater than or equal to 500 RBCs/µL or, in the absence of an available CSF RBC count, CSF that is described as bloody in appearance in a medical record.

^§Suggested parameters for abnormal CSF WBC count may be found in the most recent CDC STI Treatment Guidelines or equivalent CDC clinical management guidelines. Whenever possible, the treating clinician should be consulted to interpret the CSF values for the specific patient.

Epidemiologic Linkage

A stillborn infant, liveborn infant, or child born to a woman with untreated or inadequately^** treated syphilis at delivery.

^** Inadequate treatment for a non-pregnant woman is any treatment given that differs from the recommended or alternative treatments listed in the CDC STI Treatment Guidelines or equivalent CDC clinical management guidelines. Inadequate treatment in pregnancy is anything other than completion of a recommended regimen, in accordance with the CDC STI Treatment Guidelines or equivalent CDC clinical management guidelines, initiated 30 or more days before delivery.

Vital Records Criteria

A fetal death in which syphilis is specified on the Report of Fetal Death as the cause of, or a condition contributing to, fetal death.

Case Classification

Probable

A liveborn infant or child who meets epidemiologic linkage criteria,

A liveborn infant or child who meets presumptive laboratory evidence AND the suspected or most likely source of exposure is in utero AND either:
- Meets clinical criteria, OR
- Meets supportive laboratory/radiographic evidence,

A fetal death or stillbirth that meets other fetal death/stillbirth criteria AND either:
- Meets epidemiologic linkage criteria, OR
- Meets vital records criteria.

Confirmed

A liveborn infant or child who meets confirmatory laboratory evidence AND the suspected or most likely source of exposure is in utero, OR
A fetal death or stillbirth that meets other fetal death/stillbirth criteria AND meets confirmatory laboratory evidence.

Other Criteria

Guidance for sub-classifying acquired syphilis cases

Neurologic manifestations
Ocular manifestations
Otic manifestations
Late clinical manifestations

The following provides guidance for health departments to use for the classification and notification of acquired syphilis cases with neurologic, ocular, otic, and/or late clinical manifestations of syphilis. Cases should be reported to the CDC through voluntary notification according to stage of acquired syphilitic infection, as defined above (i.e., primary syphilis, secondary syphilis, early non-primary non-secondary syphilis, or unknown duration or late syphilis) and, if identified, should include the clinical manifestations in the case data, as defined below. These manifestations do not apply to congenital syphilis cases.

Neurologic Manifestations

Background

Neurologic manifestations (neurosyphilis) can occur at any stage of syphilitic infection. If neurologic manifestations of syphilis are present in a previously unreported case of syphilis, the case should be reported with the appropriate stage of infection, and neurologic manifestations should be included with the case data.

Neurologic Clinical Criteria

Has clinical signs or symptoms consistent with infection of the central nervous system with T. pallidum, as evidenced by manifestations including syphilitic meningitis, meningovascular syphilis, general paresis, or tabes dorsalis, without other clear causes for these clinical abnormalities.

Neurologic Laboratory Criteria

A reactive CSF VDRL or CSF RPR test in the absence of visibly blood-contaminated CSF^†††, OR
Direct detection of T. pallidum in CSF by nucleic acid amplification test (e.g., PCR, LAMP) or diagnostically equivalent molecular method.

^†††For the purposes of the syphilis surveillance case definition, visibly blood-contaminated CSF is defined as a CSF red blood cell (RBC) count of greater than or equal to 500 RBCs/µL or, in the absence of an available CSF RBC count, CSF that is described as bloody in appearance in a medical record.

Neurologic Sub-classifications

Verified:

Meets the surveillance case definition for primary, secondary, or early non-primary non-secondary syphilis AND meets neurologic clinical criteria AND meets neurologic laboratory criteria, OR
Has a reactive blood-based treponemal antibody test result^¶ AND has a current (i.e., a test performed in the context of this index presentation) reactive blood-based nontreponemal antibody test result^# AND meets neurologic clinical criteria AND meets neurologic laboratory criteria.

Likely:

Meets the surveillance case definition for primary, secondary, or early non-primary non-secondary syphilis AND meets neurologic clinical criteria AND a diagnosis of neurosyphilis was made by a clinical provider, OR
Has a reactive blood-based treponemal antibody test result^¶ AND has a current (i.e., a test performed in the context of this index presentation) reactive blood-based nontreponemal antibody test result^# AND meets neurologic clinical criteria AND a diagnosis of neurosyphilis was made by a clinical provider, OR
Meets the surveillance case definition for primary, secondary, or early non-primary non-secondary syphilis AND meets neurologic clinical criteria AND treatment for neurosyphilis was advised, ordered, or initiated by a clinical provider, OR
Has a reactive blood-based treponemal antibody test result^¶ AND has a current (i.e., a test performed in the context of this index presentation) reactive blood-based nontreponemal antibody test result^# AND meets neurologic clinical criteria AND treatment for neurosyphilis was advised, ordered, or initiated by a clinical provider.

# See case definition for syphilis, unknown duration or late.

^¶Current or historical reactive treponemal antibody tests can be used to satisfy this criterion.

Ocular Manifestations

Background

Ocular manifestations (ocular syphilis) can occur at any stage of syphilitic infection. If ocular manifestations of syphilis are present in a previously unreported case of syphilis, the case should be reported with the appropriate stage of infection, and ocular manifestations should be included with the case data.

Ocular Clinical Criteria

Has clinical signs or symptoms consistent with infection of any eye structure with T. pallidum, as evidenced by manifestations including posterior uveitis, panuveitis, anterior uveitis, conjunctivitis, optic neuropathy, retinal vasculitis, and interstitial keratitis, without other clear causes for these clinical abnormalities. Ocular syphilis may lead to permanent decreases in visual acuity, including permanent blindness.

Ocular Laboratory Criteria

Direct detection of T. pallidum in aqueous or vitreous fluid by nucleic acid amplification test (e.g., PCR, LAMP) or diagnostically equivalent molecular method.

Ocular Sub-classifications

Verified:

Meets the surveillance case definition for primary, secondary, or early non-primary non-secondary syphilis AND meets ocular clinical criteria AND meets ocular laboratory criteria, OR
Has a reactive blood-based treponemal antibody test result^¶ AND has a current (i.e., a test performed in the context of this index presentation) reactive blood-based nontreponemal antibody test result^# AND meets ocular clinical criteria AND meets ocular laboratory criteria.

Likely:

Meets the surveillance case definition for primary, secondary, or early non-primary non-secondary syphilis AND meets ocular clinical criteria AND a diagnosis of ocular syphilis was made by a clinical provider, OR
Has a reactive blood-based treponemal antibody test result^¶ AND has a current (i.e., a test performed in the context of this index presentation) reactive blood-based nontreponemal antibody test result^# AND meets ocular clinical criteria AND a diagnosis of ocular syphilis was made by a clinical provider, OR
Meets the surveillance case definition for primary, secondary, or early non-primary non-secondary syphilis AND meets ocular clinical criteria AND treatment for ocular syphilis was advised, ordered, or initiated by a clinical provider, OR
Has a reactive blood-based treponemal antibody test result^¶ AND has a current (i.e., a test performed in the context of this index presentation) reactive blood-based nontreponemal antibody test result^# AND meets ocular clinical criteria AND treatment for ocular syphilis was advised, ordered, or initiated by a clinical provider.

# See case definition for syphilis, unknown duration or late.

^¶Current or historical reactive treponemal antibody tests can be used to satisfy this criterion.

Otic Manifestations

Background

Otic manifestations (otosyphilis) can occur at any stage of syphilitic infection. If otic manifestations of syphilis are present in a previously unreported case of syphilis, the case should be reported with the appropriate stage of infection, and otic manifestations should be included with the case data.

Otic Clinical Criteria

Has clinical signs or symptoms consistent with infection of the cochleovestibular system with T. pallidum, as evidenced by manifestations including tinnitus, vertigo, and sensorineural or conductive hearing loss that can be permanent, without other clear causes for these clinical abnormalities.

Otic Laboratory Criteria

Direct detection of T. pallidum in inner ear fluid by nucleic acid amplification test (e.g., PCR, LAMP) or diagnostically equivalent molecular method.

Otic Sub-classifications

Verified:

Meets the surveillance case definition for primary, secondary, or early non-primary non-secondary syphilis AND meets otic clinical criteria AND meets otic laboratory criteria, OR
Has a reactive blood-based treponemal antibody test result^¶ AND has a current (i.e., a test performed in the context of this index presentation) reactive blood-based nontreponemal antibody test result^# AND meets otic clinical criteria AND meets otic laboratory criteria.

Likely:

Meets the surveillance case definition for primary, secondary, or early non-primary non-secondary syphilis AND meets otic clinical criteria AND a diagnosis of otosyphilis was made by a clinical provider, OR
Has a reactive blood-based treponemal antibody test result^¶ AND has a current (i.e., a test performed in the context of this index presentation) reactive blood-based nontreponemal antibody test result^# AND meets otic clinical criteria AND a diagnosis of otosyphilis was made by a clinical provider, OR
Meets the surveillance case definition for primary, secondary, or early non-primary non-secondary syphilis AND meets otic clinical criteria AND treatment for otosyphilis was advised, ordered, or initiated by a clinical provider, OR
Has a reactive blood-based treponemal antibody test result^¶ AND has a current (i.e., a test performed in the context of this index presentation) reactive blood-based nontreponemal antibody test result^# AND meets otic clinical criteria AND treatment for otosyphilis was advised, ordered, or initiated by a clinical provider.

# See case definition for syphilis, unknown duration or late.

^¶Current or historical reactive treponemal antibody tests can be used to satisfy this criterion.

Late Clinical Manifestations

Background

Late clinical manifestations of syphilis (tertiary syphilis) usually develop after a period of 10 or more years of untreated syphilitic infection. Therefore, if late clinical manifestations of syphilis are present in a previously unreported case of syphilis, the case should be reported as syphilis, unknown duration or late and late clinical manifestations should be included with the case data.

Late Clinical Criteria

In the absence of other clear causes for the clinical abnormalities,

Characteristic abnormalities or inflammatory lesions of the cardiovascular system (e.g., aortitis, coronary vessel disease), skin (e.g., gummatous lesions), bone (e.g., osteitis), or other tissues/structures (e.g., upper and lower respiratory tracts, mouth, eye, abdominal organs, reproductive organs, lymph nodes, central nervous system, and skeletal muscle).

Late Clinical Laboratory Criteria

Direct detection of T. pallidum by IHC staining in a specimen from a late lesion that was both not obtained from the oropharynx and not potentially contaminated by stool, OR
Direct detection of T. pallidum by nucleic acid amplification test (e.g., PCR, LAMP) or a diagnostically equivalent molecular method in any specimen from a late lesion, OR
Demonstration of pathologic changes that are consistent with T. pallidum infection on histologic examination of late lesions.

Late Clinical Sub-classifications

Verified^#:

Has a current (i.e., a test performed in the context of this index presentation) reactive blood-based treponemal antibody test result AND meets late clinical criteria AND meets late clinical laboratory criteria, OR
Clinical signs and symptoms consistent with late neurologic manifestations of syphilis (i.e., general paresis or tabes dorsalis) in a case that meets the sub-classification criteria for verified neurologic manifestations of syphilis.

Likely^#:

Has a current (i.e., a test performed in the context of this index presentation) reactive blood-based treponemal antibody test result AND meets late clinical criteria AND a diagnosis of late clinical manifestations was made by a clinical provider, OR
Has a current (i.e., a test performed in the context of this index presentation) reactive blood-based treponemal antibody test result AND meets late clinical criteria AND treatment for late clinical manifestations was advised, ordered, or initiated by a clinical provider, OR
Clinical signs and symptoms consistent with late neurologic manifestations of syphilis (i.e., general paresis or tabes dorsalis) in a case that meets the sub-classification criteria for likely neurologic manifestations of syphilis.

# See case definition for syphilis, unknown duration or late.

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Last Reviewed: June 2, 2026

Source: Office of Public Health Data, Surveillance, and Technology