Syphilis is a common sexually transmitted infection. An estimated 6 million new infections occurred worldwide in 2016. Incidence of congenital, primary, and secondary syphilis is increasing.
Caused by the spirochaetal bacterium Treponema pallidum, subspecies pallidum.
Clinical presentation is often asymptomatic, but can manifest in a number of ways.
A painless ulcer (chancre) in the anogenital region is a hallmark of primary infection.
Diagnosis is usually straightforward after clinical examination and serological tests.
Syphilis infection is treated with penicillin.
Untreated syphilis facilitates HIV transmission and causes considerable morbidity, such as cardiovascular and neurological disease, as well as a congenital syndrome in the newborn.
Syphilis in pregnancy is a major cause of miscarriage, stillbirth, and perinatal morbidity and mortality in some parts of the world.
Syphilis is a sexually transmitted infection caused by the spirochaetal bacterium Treponema pallidum, subspecies pallidum. It is found only in human hosts. Infection is typically acquired through direct person-to-person sexual contact with an individual who has early (primary or secondary) syphilis. Most sexual transmission of syphilis probably occurs from direct contact with syphilitic lesions on the genitals or mucous membranes. Transmission from mother to fetus during pregnancy causes congenital infection. Syphilis has often been described as the great imitator because many of the symptoms and signs are difficult to distinguish from other diseases.
History and exam
Key diagnostic factors
- presence of risk factors
- anogenital ulcer
- diffuse rash
- constitutional symptoms
- rhinitis (congenital syphilis)
- hepatosplenomegaly (congenital syphilis)
- patchy alopecia
- condylomata lata
- memory impairment, altered mood, confusion, or dementia
- visual changes
- Argyll-Robertson pupils
- loss of sense of vibration, proprioception, and position sense
- loss of anal and bladder sphincter control
- positive Romberg's sign
- diastolic murmur
- rubbery lesions/nodules with a necrotic centre
- miscarriage, stillbirth, or neonatal death (congenital syphilis)
- premature labour and intrauterine growth retardation (congenital syphilis)
- neonatal skin rash (congenital syphilis)
- tibial bowing (congenital syphilis)
- craniofacial malformation (congenital syphilis)
- tooth abnormalities (congenital syphilis)
- necrotising funisitis (congenital syphilis)
Other diagnostic factors
- mouth ulcer
- asymptomatic with positive serology (latent syphilis)
- eye pain
- hearing loss
- peripheral oedema
- peripheral neuropathy
- skin or visceral organ perforation or collapse of structure
- neonatal neurological abnormalities (congenital syphilis)
- sexual contact with an infected person
- men who have sex with men (MSM)
- illicit drug use
- commercial sex workers
- multiple sexual partners
- people with HIV or other STIs
- syphilis during pregnancy (risk for congenital syphilis)
1st investigations to order
- dark-field microscopy of swab from lesion
- serum treponemal enzyme immunoassay (EIA)
- serum Treponema pallidum particle agglutination (TPPA)
- serum Treponema pallidum haemagglutination (TPHA)
- serum fluorescent treponemal antibody absorption (FTA-ABS) test
- immunocapture assay
- line immunoassay (LIA) serological test
- serum rapid plasma reagin (RPR) test
- serum Venereal Disease Research Laboratory (VDRL) test
Investigations to consider
- lumbar puncture, cerebrospinal fluid (CSF) analysis
- chest x-ray
- computed tomography brain
- magnetic resonance imaging brain
- HIV test
- fetal ultrasound scan
- full blood count
- long-bone x-rays
- liver enzymes (aspartate aminotransferase, alanine aminotransferase and alkaline phosphatase) and bilirubin
- auditory brainstem response
- fetal skeletal survey
- Treponema pallidum polymerase chain reaction (PCR) (sample taken directly from ulcerative lesions)
- point of care (POC) testing with either treponemal or combination treponemal/non-treponemal antibody
adults with suspected early infection or sexual contacts of patients with confirmed infection
adults without neurosyphilis
adults with neurosyphilis
Juan C. Salazar, MD, MPH, FAAP
Professor and Chair
Department of Pediatrics
University of Connecticut School of Medicine
Physician in Chief
JCS is the author of references cited in this topic.
Adriana R. Cruz, MD
ARC declares that she has no conflicting interests.
Dr Juan C. Salazar and Dr Adriana R. Cruz would like to gratefully acknowledge Dr Jairo M. Montezuma-Rusca, Nicholas Bennett, Patrick French, and Nooshin Barmania, previous contributors to this topic.
PF is an author of a reference cited in this topic. JMMR, NB, and NB declare that they have no competing interests.
Robert A. Larsen, MD
Associate Professor of Medicine
University of Southern California
Keck School of Medicine
RAL declares that he has no competing interests.
William Rodriguez, MD
Assistant Professor of Medicine
Harvard Medical School
Director of Research
Global Health Delivery Project
Harvard School of Public Health
WR declares that he has no competing interests.
Jennifer Handforth, MB ChB, MRCPCH, DTM&H
Croydon University Hospital
JH declares that she has no competing interests.
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