International Classification (ICD) A53.-


Syphilis is a sexually transmitted disease (STD) caused by bacteria, which is caused by the pathogen Treponema pallidum. In medical circles, syphilis is sometimes called lues venerea, but some people also know the disease by the name hard chancre or French disease.

It is typical of syphilis that the disease progresses in different stages. In times when there were no antibiotics, especially the last (=4th) stage was very feared because of the damage to the nervous system. Nowadays, however, syphilis can be well controlled by antibiotic therapy. However, if the disease is not treated, it can lead to consequential damage or even death.

In the 1990s, there was a sharp decline in syphilis cases because many people protected themselves adequately during sexual intercourse for fear of HIV infection. In recent years, however, there has been an increasing neglect of protection during sexual intercourse, so that the infection rates of STDs have risen again.

The peak of the disease is between the ages of 30 and 40, and men are more likely to be affected by syphilis than women. Any infection with the syphilis pathogen is subject to mandatory notification to the public health department.


Syphilis is caused by an infection with the bacterium Treponema pallidum. Transmission of the pathogen occurs through unprotected sexual intercourse. The bacterium forms small ulcers in the genital area, which in turn are sources of further transmission. However, Treponema pallidum can also be transmitted through other forms of sexual contact, such as anal or oral sex. The risk of contracting syphilis increases significantly in people who have frequently changing sexual partners.

Women can also infect their growing child through the placenta during pregnancy. If the fetus becomes infected during pregnancy, this can lead to so-called connatal syphilis, resulting in miscarriage or congenital malformations.

It is not possible to transmit syphilis via contaminated toilet facilities, swimming pools or eating utensils, nor via blood supplies.


Syphilis, if not adequately treated, has a typical course of disease, which is divided into four stages. The first and second stages are grouped together as early syphilis, stages three and four together are called late syphilis.

Primary stage (1st stage)

The incubation period, that is, the time from infection to the appearance of the first symptoms, can be between 10 and 90 days. After this incubation period, an ulcer may become visible on the skin or mucous membrane site where the pathogen previously entered. This is also known as the primary effect or hard chancre. Since syphilis is most commonly transmitted through sexual intercourse, such ulcers are usually found on the penis or vagina. If an ulcer occurs in the intimate area, syphilis should always be considered. However, after anal intercourse such an ulcer can also be found in the intestine and after oral intercourse in the mouth.

This is a reddened ulcer, which usually secretes a highly infectious secretion. Subsequently, the neighboring lymph nodes are affected by the infection, which is noticeable by a swelling of these. Even without antibiotic therapy, the ulcer usually heals after a few weeks.

Secondary stage (stage 2)

This stage, which occurs about three to six weeks after the first symptoms, is characterized by non-specific symptoms, such as increased body temperature, fatigue, and limb and head pain. In addition, many lymph nodes may swell all over the body. After a further two weeks, a skin rash appears, initially with tender, faintly reddened patches. Subsequently, these spots develop into coarse, dark nodules, also known as poplars. Particularly large poplars are known as condylomata lata, which may burst and thus secrete large quantities of infectious secretion. In some cases, such syphilis lesions are also visible of the mucous membrane of the mouth or genital area. Hair loss is also seen in very rare cases.

These changes in the skin and mucous membranes regress after up to four months, but may recur repeatedly within 2 years without adequate treatment.

Latent phase

After the stages of early syphilis, the disease may become sessile in many affected individuals. However, from the latent phase, the disease may re-emerge after a long time and lead to the so-called late syphilis. Even in the latent phase of syphilis, there are still bacteria in the body of the diseased person, which is why there is also a risk of infection at this time. However, the more time that passes without symptoms appearing, the less risk there is of infecting others.

Tertiary stage (3rd stage)

About three to five years after the local symptoms (ulcers, swollen lymph nodes), the disease can take a systemic course. A wide variety of organs of the body are affected, such as blood vessels, respiratory tract, gastrointestinal tract, muscles and bones. In addition, rubbery hardened nodes called gums (singular: gumma) form in the affected organs.

These nodules can open up, causing damage to the surrounding tissue. If such gummas occur in the area of the aorta (main artery), this can lead to bulging of the vessel walls (aneurysm), which can be life-threatening.

Neurolues (4th stage)

If syphilis continues to be inadequately treated, the disease reaches a stage ten to twenty years after onset where severe damage to the nervous system occurs. In about 25% of cases, a persistent inflammation of the brain (syphilis cerebrospinalis) is observed, which leads to a steady loss of brain power and eventually to dementia.

Furthermore, syphilis can also affect the spinal cord as well as nerve roots and nerves emerging from it. Initially, this is noticeable through severe pain, and subsequently, the destruction of the nerves leads to a loss of pain and temperature perception. Organ functions that are controlled by the autonomic (unconscious) nervous system can also be impaired. For example, the control of urination and defecation may be disturbed. Furthermore, sufferers have coordination problems when walking. In the worst case, the disease can lead to paralysis.

However, this stage of syphilis is no longer observed in western countries, as the disease is easily treatable with antibiotics.


Initially, the attending physician will ask questions about symptoms and the course of the disease (anamnesis) and perform a physical examination. If syphilis is suspected, he will make a smear at the site of infection and take some blood. A bacterial culture can be prepared from the blood and the smear, which serves to detect the pathogen. If syphilis is suspected, it should also be investigated whether other venereal diseases are present.

-During early syphilis (1st and 2nd stages), detection of the pathogen can be made directly by a smear at the site of infection or ulcer by viewing the smear under the microscope.

-By means of an examination of the blood sample, antibodies directed against the syphilis pathogen can be detected. A so-called polymerase chain reaction (PCR) can be used to determine whether DNA of the bacterium is present in the blood.

If neurolues is already present, a spinal cord puncture with examination of the cerebrospinal fluid (CSF) is usually performed.

At the beginning of a pregnancy, every woman is nowadays routinely tested for syphilis, which means that infection of the newborn is now rare.



Syphilis can be treated well with antibiotic therapy. How long antibiotics need to be administered is determined primarily by the course and duration of the disease and the patient's condition.

The stages of early syphilis (1st and 2nd stage) are usually treated with penicillin for about 14 days. Depot penicillin, which is injected into the muscle (intramuscularly) once or twice, is particularly suitable. If the disease has already progressed to late syphilis, a three-week therapy is usually necessary.A therapy duration of this extent can be accompanied by flu-like side effects.

If the syphilis has already reached the stage of neurolues, a high-dose administration of penicillin is necessary.

If the affected person is allergic to penicillin, erythromycin, doxycycline or tetracycline can be administered as an alternative.

Treatment of the partner

Since syphilis is transmitted through sexual intercourse, it is necessary to examine the partner of the infected person for an infection as well. Furthermore, persons who have syphilis and are in the primary stage should contact all sexual partners of the last three months and inform them of a possible infection.

If the diagnosis is only made in the secondary stage, the affected person should even inform the sexual partners of the past two years.

The importance of having sexual partners screened for possible infection is highlighted by study results that showed an infection rate of more than 50% of sexual partners.

Follow-up examinations

After successful treatment of syphilis, follow-up examinations with blood sampling should be carried out at monthly intervals for the first three months. In addition, further follow-up examinations are recommended after six months and after one year. After that, a doctor should be seen at least once a year for follow-up.

After treated early syphilis, blood tests are usually suitable for monitoring the course of the disease. However, if the disease was not detected and treated until the late syphilis stage, blood tests do not always provide reliable results, which is why a cardiolipin test should be performed in these cases.


The prognosis of the disease is essentially determined by the stage of the disease at the time of diagnosis and by the success of treatment. While the primary and secondary stages of syphilis can also heal without drug therapy, medical treatment is definitely necessary for the stages of late syphilis, as otherwise severe, permanent damage can occur.

In most cases, irreversible consequential damage can be avoided by effective treatment, but if the disease has already reached the stage of neurolues at the start of therapy, the prospect of cure is usually poor even with consistent antibiotic therapy.


You can take certain measures to prevent an infection with the syphilis pathogen. One of the most important preventive measures is the use of condoms during sexual intercourse. In particular, people who frequently change sexual partners should pay special attention to efficient protection during sexual intercourse. Although the risk of contracting syphilis can be greatly reduced by protected sexual intercourse, it is also possible in rare cases for the pathogen to be transmitted through kissing or simple touching.

If you think you have been infected with syphilis, it is advisable to consult a doctor. This should be done as soon as possible, because a good prognosis can only be achieved through rapid treatment. Furthermore, it should be remembered that the sexual partner(s) should also be examined and treated.

Pregnant women are routinely tested for the disease as part of the mother-child passport. If the pregnant woman is really infected with the pathogen, special measures can largely prevent transmission to the fetus.

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All information used for the content comes from verified sources (recognised institutions, experts, studies by renowned universities). We attach great importance to the qualification of the authors and the scientific background of the information. Thus, we ensure that our research is based on scientific findings.
Danilo Glisic

Danilo Glisic

As a biology and mathematics student, he is passionate about writing magazine articles on current medical topics. Due to his affinity for facts, figures and data, his focus is on describing relevant clinical trial results.

The content of this page is an automated and high-quality translation from DeepL. You can find the original content in German here.



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