Spirochetes

than 1000 cases were documented.4 With focused efforts

Lesions occur on the penis, anus, and rectum in men and

to reduce syphilis in the United States, in 2000 the rate of

on the cervix, vulva, and perineum in women. Small lesions

primary and secondary syphilis was 2.1 cases per 100 000

may also occur on the lips, tongue, buccal mucosa, and skin,

population, the lowest since reporting began in 1941.5

and chancres of the eyelids and conjunctiva have also been

From 2001 to 2004, rates increased to 2.7 cases per 100 000

described.10

population. Approximately 84% of cases occurred in men.

Primary and secondary syphilis incidence also varied by

Secondary syphilis.  If untreated, disease in patients with

race/ethnicity. The incidence of primary and secondary syph-

primary syphilis will progress to secondary syphilis 4–10

ilis in 2004 was 9.0 per 100 000 population among blacks,

weeks after the initial manifestations of the disease. One of

1.6 among whites, 3.2 among Hispanics, 1.2 among Asian/

the unique characteristics of syphilis is that it always dis-

Pacific Islanders, and 3.2 among American Indian/Alaska

seminates.11 The skin is involved in about 90% of patients

Natives. Syphilis is also a problem in patients co-infected

with secondary syphilis. A generalized rash is characteristic

with human immunodeficiency virus (HIV). These patients

of secondary syphilis and may be maculopapular or pustu-

may not mount a serologic response to the treponemal infec-

lar. The rash commonly occurs on the flexor and volar sur-

tion and thus elude diagnosis. In addition, standard therapy

faces of the body, typically the palms and the soles. The rash

may be insufficient to eradicate the infection in these immu-

usually resolves without scarring, but some patients are

nocompromised patients.6,7

left with areas of hyperor hypopigmentation. Mucous

T. pallidum is a spirochete that is approximately 0.01–

membranes become eroded, forming erythematous patches.

0.02 m wide and 5–20 m long. Although it cannot survive

Condylomata lata is another characteristic dermatologic

long out of the body, it can be cultured and remains viable

manifestation of secondary syphilis. The papules develop at

for several days. Syphilis is transmitted almost exclusively by

the mucocutaneous junctions and in moist areas of the skin,

sexual contact, including sexual intercourse, orogenital and

and appear as dull pink or gray hypertrophic lesions. Sys-

anorectal contact, and occasionally kissing. The disease is

temic symptoms of secondary syphilis include fever, malaise,

most infectious in patients with untreated primary syphilis

headache, nausea, anorexia, and joint pain.12 A generalized

or secondary syphilis with skin lesions. Disease can also be

lymphadenopathy is found in both primary and secondary

transmitted by patients with early latent syphilis, especially

syphilis. Syphilitic infiltration of the kidneys, liver, and gas-

if they have mucocutaneous involvement; however, disease

trointestinal tract also occurs in secondary syphilis, and

in patients with late latent syphilis and tertiary syphilis is

about 10% of patients have ocular involvement. Anterior

not infectious. Congenital syphilis occurs with transplacen-

uveitis is the predominant eye finding in early secondary

tal spread of the spirochete. Interestingly, infection with

syphilis and may be the most common ocular lesion in

syphilis does not confer lasting immunity, especially if treat-

syphilis.13 Some patients may demonstrate a cerebrospinal

ment is received early in the course of the disease.

fluid (CSF) pleocytosis, and a few of these patients experi-

T. pallidum can penetrate intact mucous membranes or

ence acute syphilitic meningitis with headache, neck stiff-

abraded skin. The period of incubation varies from 10 to 90

ness, cranial nerve palsies, and disc edema.

days, but averages 3 weeks.8 Before primary skin lesions

appear, the spirochete spreads via the lymphatics to the

Latent syphilis.  In the first year after initial infection, patients

bloodstream, from which it then disseminates.

may have recurrences of infectious mucocutaneous lesions.

As with many of the spirochetal diseases, the clinical

This period of the disease is called early latent syphilis. The

course of syphilis is divided into stages: primary, secondary,

late latent phase of syphilis occurs after 1 year of infection,

and tertiary syphilis (Box 10-1).

and during this stage of the disease infectious relapses are

Clinical Manifestations

rare. Most patients who have not been treated remain in this

late latent phase of the disease; however, about 30% go on

Primary syphilis.  The chancre is the predominant lesion of

to experience tertiary syphilis.

primary syphilis. It appears about 4 weeks after infection and

heals in about 1–2 months in untreated individuals. The

Tertiary syphilis.  Tertiary syphilis is also called late syphilis

lesion begins as an erythematous papule at the inoculation

and is often subdivided into three groups: benign tertiary

site and later erodes to form a painless ulcer. Multiple chan-

syphilis, cardiovascular syphilis, and neurosyphilis.

cres can occur, especially in patients coinfected with HIV.9

Serous fluid from these lesions is teeming with spirochetes.

Benign tertiary syphilis.  The gumma is the typical lesion of

benign tertiary syphilis and is a chronic granulomatous

lesion that heals with scarring and fibrosis. It is a rare finding

Box 10-1  Syphilis – key features

in the penicillin era and responds rapidly to treatment.

• Caused by the spirochete Treponema pallidum

Gummas tend to develop in the skin and mucous mem-

• Transmitted almost exclusively by sexual contact

branes, but can occur in almost any tissue and have even

• Congenital syphilis occurs with transplacental spread of the

been found in the choroid of the eye.14

spirochete

tertiary

lis include aortitis and aortic aneurysms, aortic valvular

•

Tertiary syphilis is subdivided into three subgroups: benign

insufficiency, and narrowing of the coronary ostia. Disease

tertiary syphilis, cardiovascular syphilis, and neurosyphilis

starts about 5–10 years after infection, but symptoms of

•

If untreated, syphilis will disseminate

cardiovascular syphilis may not be clinically evident for

more than 20 years.