What Is Syphilis?
Syphilis is a sexually transmitted disease (STD), once
responsible for devastating epidemics. It is caused by a bacterium
called Treponema pallidum. The rate of primary and
secondary syphilis in the United States declined by 89.2 percent
from 1990 to 2000. In 2000, 5,979 cases of primary and secondary
syphilis in the United States were reported to the U.S. Centers for
Disease Control and Prevention.
Of increasing concern is the fact that syphilis increases by 3-
to 5-fold the risk of transmitting and acquiring HIV (human
immunodeficiency virus), the virus that causes AIDS (acquired
How Is Syphilis Transmitted?
The syphilis bacterium is very fragile, and the infection is
almost always transmitted by sexual contact with an infected person.
The bacterium spreads from the initial ulcer (sore) of an infected
person to the skin or mucous membranes (linings) of the genital
area, mouth, or anus of an uninfected sexual partner. It also can
pass through broken skin on other parts of the body.
In addition, a pregnant woman with syphilis can pass T.
pallidum to her unborn child, who may be born with serious
mental and physical problems as a result of this infection.
What Are The Symptoms Of Syphilis?
The initial infection causes an ulcer at the site of infection.
The bacteria, however, move throughout the body, damaging many
organs over time. Medical experts describe the course of the disease
by dividing it into four stages-primary, secondary, latent, and
tertiary (late). An infected person who has not been treated may
infect others during the first two stages, which usually last 1 to 2
years. In its late stages, untreated syphilis, although not
contagious, can cause serious heart abnormalities, mental disorders,
blindness, other neurologic problems, and death.
The first symptom of primary syphilis is an ulcer called a
chancre ("shan-ker"). The chancre can appear within 10 days to 3
months after exposure, but it generally appears within 2 to 6 weeks.
Because the chancre may be painless and may occur inside the body,
the infected person might not notice it. It usually is found on the
part of the body exposed to the infected partner's ulcer, such as
the penis, vulva, or vagina. A chancre also can develop on the
cervix, tongue, lips, or other parts of the body. The chancre
disappears within a few weeks whether or not a person is treated. If
not treated during the primary stage, about one-third of people will
go on to the chronic stages.
A skin rash, with brown sores about the size of a penny, often
marks this chronic stage of syphilis. The rash appears anywhere from
3 to 6 weeks after the chancre appears. While the rash may cover the
whole body or appear only in a few areas, it is almost always on the
palms of the hands and soles of the feet.
Because active bacteria are present in the sores, any physical
contact—sexual or nonsexual—with the broken skin of an infected
person may spread the infection at this stage. The rash usually
heals within several weeks or months.
Other symptoms also may occur, such as mild fever, fatigue,
headache, sore throat, patchy hair loss, and swollen lymph glands
throughout the body. These symptoms may be very mild and, like the
chancre of primary syphilis, will disappear without treatment. The
signs of secondary syphilis may come and go over the next 1 to 2
years of the disease.
If untreated, syphilis may lapse into a latent stage during which
the disease is no longer contagious and no symptoms are present.
Many people who are not treated will suffer from no further signs
and symptoms of the disease.
Approximately one-third of people who have had secondary syphilis
go on to develop the complications of late, or tertiary, syphilis,
in which the bacteria damage the heart, eyes, brain, nervous system,
bones, joints, or almost any other part of the body. This stage can
last for years, or even for decades. Late syphilis can result in
mental illness, blindness, other neurologic problems, heart disease,
How Is Syhilis Diagnosed?
Syphilis is sometimes called "the great imitator" because its
early symptoms are similar to those of many other diseases. Sexually
active people should consult a doctor or other health care worker
about any rash or sore in the genital area. Those who have been
treated for another STD, such as gonorrhea, should be tested to be
sure they do not also have syphilis.
There are three ways to diagnose syphilis.
- Recognizing the signs and symptoms
- Examining blood samples
- Identifying syphilis bacteria under a microscope
The doctor usually uses all these approaches to diagnose syphilis
and decide upon the stage of infection.
Blood tests also provide evidence of infection, although they may
give false-negative results (not show signs of an infection despite
its presence) for up to 3 months after infection. False-positive
tests (showing signs of an infection when it is not present) also
can occur. Therefore, two blood tests are usually used.
Interpretation of blood tests for syphilis can be difficult, and
repeated tests are sometimes necessary to confirm the diagnosis.
How Is Syphilis Treated?
Unfortunately, the early symptoms of syphilis can be very mild,
and many people do not seek treatment when they first become
Doctors usually treat patients with syphilis with penicillin,
given by injection. They use other antibiotics for patients allergic
to penicillin. A person usually can no longer transmit syphilis 24
hours after starting treatment. Some people, however, do not respond
to the usual doses of penicillin. Therefore, it is important that
people being treated for syphilis have periodic blood tests to check
that the infectious agent has been completely destroyed.
People with neurosyphilis may need to be retested for up to 2
years after treatment. In all stages of syphilis, proper treatment
will cure the disease. But in late syphilis, damage already done to
body organs cannot be reversed.
What Are The Effects Of Syphilis In Pregnant Women?
A pregnant woman with untreated, active syphilis is likely to
pass the infection to her unborn child. In addition, miscarriage may
occur in as many as 25 to 50 percent of women acutely infected with
syphilis during pregnancy. Between 40 to 70 percent of women with
active syphilis will give birth to a syphilis-infected infant.
Some infants with congenital syphilis may have symptoms at birth,
but most develop symptoms between 2 weeks and 3 months later. These
symptoms may include
- Skin ulcers
- Weakened or hoarse crying sounds
- Swollen liver and spleen
- Yellowish skin (jaundice)
- Anemia (low red blood cell count)
- Various deformities
People who care for infants with congenital syphilis must use
special cautions because the moist sores are infectious.
Rarely, the symptoms of syphilis go undetected in infants. As
infected infants become older children and teenagers, they may
develop the symptoms of late-stage syphilis, including damage to
their bones, teeth, eyes, ears, and brains.
Can Syphilis Cause Other Complications?
Syphilis bacteria frequently invade the nervous system during the
early stages of infection. Approximately 3 to 7 percent of persons
with untreated syphilis develop neurosyphilis, a sometimes serious
disorder of the nervous system. In some instances, the time from
infection to developing neurosyphilis may be up to 20 years.
Some people with neurosyphilis never develop any symptoms. Others
may have headache, stiff neck, and fever that result from an
inflammation of the lining of the brain. Some people develop
seizures. People whose blood vessels are affected may develop
symptoms of stroke with numbness, weakness, or visual problems.
Neurosyphilis may be more difficult to treat, and its course may be
different, in people with HIV infection or AIDS.
How Can Syphilis Be Prevented?
The open sores of syphilis may be visible and infectious during
the active stages of infection. Any contact with these infectious
sores and other infected tissues and body fluids must be avoided to
prevent spread of the disease. As with many other STDs, using latex
male condoms properly during sexual intercourse may give some
protection from the disease.
Screening and treatment of infected individuals, or secondary
prevention, is one of the few options for preventing the advanced
stages of the disease. Testing and treatment early in pregnancy are
the best ways to prevent syphilis in infants and should be a routine
part of prenatal care.
What Research Is Going On?
New tests are
being developed that may provide better ways to diagnose syphilis
and define the stage of infection.
In an effort to stem the spread of syphilis, scientists are
conducting research on the development of a vaccine. Molecular
biologists are learning more about the various surface components of
the syphilis bacterium that stimulate the immune system to respond
to the invading organism. This knowledge will pave the way for
development of an effective vaccine that can ultimately prevent this
A high priority for researchers is developing a diagnostic test
that does not require a blood sample. Saliva and urine are being
evaluated to see whether they would work as well as blood.
Researchers also are trying to develop other diagnostic tests for
detecting infection in babies.
Another high research priority is the development of a safe,
effective single-dose oral antibiotic therapy for syphilis. Many
patients do not like getting an injection for treatment, and about
10 percent of the general population is allergic to penicillin.
The genome of the bacterium that causes syphilis has been
sequenced through NIAID-funded research. The DNA sequence represents
an encyclopedia of information about the bacterium. Clues as to how
to diagnose, treat, and vaccinate against syphilis have been
identified and are fueling intensive research efforts on this
ancient but intractable disease.
Keeping on Top of Your Condition
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For More Information
National STD and AIDS Hotline
1-800-227-8922 or 1-800-342-2437
(24 hours a day, 7 days a week)
National Institute of Allergy and Infectious Diseases
Institutes of Health
31 Center Drive, MSC 2520
National Library of Medicine
Bethesda, MD 20894
Centers for Disease Control and Prevention
Atlanta, GA 30333
American Social Health Association
P.O. Box 13827
Triangle Park, NC 27709-9940