eMedicine Specialties > Emergency Medicine > Infectious Diseases

Syphilis

Author: Todd A McGregor, MD, Staff Physician, Department of Emergency Medicine, University of Southern California/Los Angeles County
Coauthor(s): Allison J Richard, MD, Instructor of Clinical Emergency Medicine, Keck School of Medicine, University of Southern California; Consulting Staff, Department of Emergency Medicine, LAC-USC Medical Center; Bradley Pulver, MD, Assistant Director, Department of Emergency Medicine, Englewood Hospital and Medical Center
Contributor Information and Disclosures

Updated: Apr 24, 2006

Introduction

Background

Syphilis is an infectious disease caused by the spirochete Treponema pallidum. It almost always is transmitted by sexual contact with infectious lesions, but it also can be transmitted in utero and via blood transfusion.

Syphilis has a myriad of presentations and can mimic many other infections and immune-mediated processes in advanced stages. Hence, it has earned the nickname "the great imposter." The complex and variable manifestations of the disease prompted Sir William Osler to remark that, "The physician who knows syphilis knows medicine."

Pathophysiology

T pallidum is a fragile spiral bacterium 6-15 micrometers long by 0.25 micrometers in diameter. It can survive only briefly outside of the body; thus transmission almost always requires direct contact with the infectious lesion(s).

T pallidum penetrates abraded skin or intact mucous membranes easily and disseminates rapidly, although asymptomatically, via the blood vessels and lymphatics.

The prominent histologic features of the human response to the presence of T pallidum are vascular changes with associated endarteritis and periarteritis. Additionally, chronic infection can result in granulomatous lesions called gummas.

The initial lesion of primary syphilis develops at the site of transmission after an incubation period of 10-90 days, with a mean of about 21-28 days, and then heals spontaneously in 3-7 weeks.

Secondary syphilis develops about 4-10 weeks after the appearance of the primary lesion and has a wide range of presentations. The most common systemic manifestations include malaise, fever, myalgias, and arthralgias with a generalized body rash and lymphadenopathy. These manifestations are termed the dermatitis-arthritis syndrome. During secondary infection, the immune reaction is at its peak and antibody titers are high.

Symptomatic secondary syphilis usually resolves without treatment. The disease then enters a latent stage that may be divided into early and late latent phases. Early latent syphilis is defined as follows: acquired syphilis within the preceding year, that is, (1) documented seroconversion; (2) unequivocal symptoms of primary or secondary syphilis; or (3) partner documented with primary, secondary, or early latent syphilis. Occasional relapses of active secondary lesions can occur. Late latent syphilis is defined as seroreactivity, in the absence of symptoms, greater than 2 years after inoculation. During the late latent stage, patients typically do not have infectious lesions. Tertiary syphilis is defined as seroreactivity greater than 2 years with symptoms. This can include all organ systems and, as alluded to earlier, manifests in many ways. As many as 40% of untreated infections can develop into tertiary disease.

Congenital syphilis is not addressed in this article.

Frequency

United States

Incidence of primary and secondary syphilis was about 100,000 cases in 1941 when reporting first began. Incidence declined steadily with the advent of antibiotic therapy to less than 10,000 cases by 1956. Over the next 25 years, the incidence of syphilis rose to about 35,000 by the early 1980s and then began to decrease again because of safer sexual practices associated with the AIDS epidemic of the 1980s. In 1990, 45,000 cases were reported. The incidence then declined to 16,500 in 1995 and went on to a brief nadir in 2000. Steadily, however, the incidence has increased, perhaps secondary to a nation wide effort by the Centers for Disease Control and Prevention (CDC) to irradicate the disease from the United States, which has led to better identification and reporting. In 2004, the overall incidence was 7,980 cases. The South continued to have the highest rates than any other region in the United States at 3.6 per 100,000.

Mortality/Morbidity

Mortality from syphilis can occur, but it is most likely due to complications of late disease. In this stage, death may result in approximately 20% of untreated patients.

Morbidity of primary and secondary syphilis ranges from the annoyance of the primary lesion to the more significant constitutional systemic symptoms of secondary syphilis. However, the progression to tertiary syphilis can result in serious permanent disability and sometimes death.

T pallidum is sensitive to penicillins and is easily treatable in the early stages.

Race

The disease still disproportionately affects black men, but the frequency of infections in blacks and whites has changed from, at one time 65:1 to currently 6:1 (black-to-white ratio).

The lowest incidence is among Native Americans.

Sex

Recent increases in incidence reflect new infections primarily among men. The ratio of male-to-female infections has risen from 1.2 in 1996 to 11.6 in 2004, suggesting that cases of men who have sex with men is primarily on the rise.

Some studies suggest that women with suspected sexually transmitted diseases (STDs) are screened for syphilis less often than men. This raises concerns about underdiagnosis in women.

High-risk groups include men having sex with men, inmates in correctional facilities, and those engaging in high-risk sexual activity.

Age

Syphilis is most common during the years of peak sexual activity. However, increased numbers of elderly persons are being diagnosed, presumably because of drugs that enable sexual activity among this age group.

• Most new cases occur in both men and women aged 15-39 years, with the highest infection rates in persons aged 20-29 years.
• Since latent syphilis can persist for years or decades, the manifestations of tertiary syphilis often occur much later in life.

Clinical

History

Since the manifestations of syphilis (particularly advanced syphilis) are nonspecific and may masquerade as many other diseases, the physician must keep a high index of suspicion regarding the possible diagnosis of syphilis during the workup.

The clinician should carefully reconstruct the time course and description of all symptoms and lesions and obtain a complete sexual history, including information about condom use and the number and symptomatology of all partners.

The United States Preventive Services Task Force (USPSTF) issued screening guidelines to include all pregnant women and people at risk of acquiring syphilis.

• Primary syphilis
  • Genital chancre - "Painless" until examined, then may be tender
  • Frequently solitary, may be multiple (Sometimes seen as "kissing" lesions on opposing skin surfaces, for example the labia.)
• Patchy alopecia
• Secondary syphilis
  • Rash - Bilaterally symmetric
  • Asymptomatic
  • Positive serology
• Tertiary syphilis
  • Mental status may be altered.
  • Patients may have symptoms related to the cardiovascular, musculoskeletal, or central nervous systems.
  • Serologic findings are often negative.

Physical

Conduct the physical examination with the manifestations of primary, secondary, and tertiary syphilis in mind. The lesions and exanthem of primary and secondary syphilis are infectious, thus, gloves must be worn.

• Primary syphilis
  • The chancre of primary syphilis usually begins as a single, painless papule that rapidly becomes eroded and indurated. The ulcer has a cartilaginous consistency at the edge and base.
  • Chancres usually are located on the penis in heterosexual men, but in homosexual men may be found in the anal canal, mouth, or external genitalia. Common primary sites in women include the cervix and labia.
  • Atypical primary lesions are common and may manifest as a papular lesion without subsequent ulceration or induration.
  • The primary lesion usually is associated with regional lymphadenopathy that may be unilateral or bilateral. Inguinal adenitis is usually discrete, firm, mobile, and painless, without overlying skin changes.
• Secondary syphilis
  • Secondary syphilis may present in many different ways but usually includes a localized or diffuse mucocutaneous rash and generalized nontender lymphadenopathy. The exanthem may be macular, papular, pustular, or mixed.
  • Typical early lesions are usually less than 20, round, discrete, nonpruritic, and symmetric macules distributed on the trunk and proximal extremities. Red papular lesions also may appear on the palms, soles, face, and scalp and may become necrotic. Patchy and nonpatchy alopecia may occur. In intertriginous areas, papules may coalesce to form highly infectious lesions called condylomata lata. Lesions usually progress from red, painful, and vesicular to "gun metal grey" as the rash resolves.
  • Mucous patches are superficial mucosal erosions, usually painless, that may develop on the tongue, oral mucosa, lips, vulva, vagina, and penis.
  • Constitutional symptoms of secondary syphilis include malaise, sore throat, headache, fever, anorexia, and, rarely, meningismus.
  • Other, less common, manifestations of secondary syphilis include gastrointestinal involvement, hepatitis, nephropathy, proctitis, arthritis, and optic neuritis.
• Symptomatic tertiary syphilis is the result of a chronic, progressive inflammatory process that eventually produces clinical symptoms years to decades after the initial infection.
• Gummatous syphilis manifests as coalescent granulomatous lesions that usually affect skin, bone, and mucous membranes, but may involve any organ system. The lesions often cause local destruction of the affected organ system.
• Cardiovascular syphilis results from endarteritis of the aorta, subsequent medial necrosis, aortitis, and aneurysm formation. Other large arteries may be affected as well.
• Neurosyphilis may be asymptomatic or symptomatic. In asymptomatic neurosyphilis, no signs or symptoms are present, but cerebral spinal fluid (CSF) abnormalities are demonstrable, including possible pleocytosis, elevated protein, decreased glucose, or a reactive CSF Venereal Disease Research Laboratory (VDRL) test.
  • Symptomatic neurosyphilis may manifest as syphilitic meningitis, meningovascular syphilis, or parenchymatous neurosyphilis.
  • Syphilitic meningitis usually develops within several years of initial infection, and patients present with typical symptoms of meningitis, including headache, nausea and vomiting, and photophobia, but are typically afebrile. Patients may exhibit cranial nerve abnormalities.
  • Meningovascular syphilis manifests 5-10 years after infection and is the result of endarteritis, which affects small blood vessels of the meninges, brain, and spinal cord. Patients may present with CNS vascular insufficiency or outright stroke.
  • Parenchymatous neurosyphilis results from direct parenchymal CNS invasion by T pallidum and is usually a late development (15-20 years after primary infection).
  • Patients present with ataxia, incontinence, paresthesias, and loss of position, vibratory, pain, and temperature sensations. Paresis and dementia, with changes in personality and intellect, may develop.

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