Syphilis is a sexually transmitted disease. Did you know that, every year, around six million people between the ages of 15 and 49 become infected with syphilis worldwide? In the United States alone, 100,000 new cases of syphilis were reported in 2019. The disease is classified as a dangerous sexually transmitted infection (STI) because, even though it is easily curable, it can lead to serious health problems if left untreated. These include, for example, neurological conditions and heart disease.
People mainly become infected with syphilis during sex, and men are particularly often affected. Many do not notice the infection and unknowingly infect others with syphilis. Pregnant women can also transmit the bacteria to their babies. This increases the risk of stillbirths and serious health damage.
Read this article to find out exactly what syphilis is and who is often affected by this STI. In what ways can you get infected during sex, and what are common syphilis symptoms? How long are those affected contagious, and how is syphilis treated – and what is the cure for syphilis? Read our article to find out more!
What Is Syphilis?
Syphilis (also called lues or Great Pox) is a venereal disease caused by the spiral-shaped bacterium Treponema pallidum. The bacterium is transmitted by infected persons mostly during sex by the mucous membranes of the penis, vagina, mouth, or anus and causes various symptoms and discomfort that can occur all over the body.
Syphilis symptoms are typically split into three successive stages – interrupted by a symptom-free phase that can last for years.
What Is Syphilis Known as?
Where exactly syphilis came from is still disputed among experts: Was it brought to Europe from the United States or was it already rampant and first brought to North America by Columbus and then taken back again?
One thing is certain: When Christopher Columbus returned from his voyage of discovery to Spain in 1492, his sailors had syphilis. In subsequent European wars, Italian and French soldiers became infected with the venereal disease. The returning French troops then triggered the first syphilis epidemic in Europe. This is why syphilis was known as the French disease for a long time. The venereal disease spread rapidly through all social classes in Europe and also reached Asian countries.
In the past, every population affected by syphilis blamed their neighboring country, often even hostile countries, for the disease. So in addition to being known as the French disease, there were other names inferring the disease was brought over from countries such as Poland, Spain, and Germany.
Who Is Most Likely to Get Syphilis?
Men are particularly often affected by syphilis – in fact, more than 90 percent of all syphilis infections are diagnosed in men. Women between 25 and 29 years old are most frequently affected in terms of age groups, and among men, the age group where most syphilis cases are reported are within the 30-to-39-year-olds.
Most people become infected with syphilis through unprotected sexual intercourse. Men often become infected during sex with men; in women, infections occur predominantly through heterosexual intercourse.
The following groups of people have an increased risk of syphilis infection:
- Men who have sex with men (MSM)
- Sex workers
- People with frequently changing sexual partners
- HIV-positive people
- People whose partner is infected with syphilis
Did you know that there is a link between HIV and syphilis? Data shows that about half of all gay or bisexual men who have syphilis are also infected with HIV? People with syphilis have an increased risk of also becoming infected with HIV because the subsequent skin and mucous membrane wounds also make it easier for HIV viruses to enter the body.
Syphilis Transmission: How Do You Contract Syphilis?
Syphilis is most often transmitted during sex. Infected persons develop small red nodules – later ulcers – on the skin or mucous membranes where the bacterial fluid leaks out. These sores are also called “hard chancres.” Syphilis bacteria are transmitted to sexual partners through the smallest injuries to the mucous membranes or skin in the genital or anal area and in the mouth.
Syphilis can be transmitted through contaminated needles, other contaminated objects, and blood transfusions, but this is very rare. However, infected pregnant women can pass the bacteria on to their babies through the placenta.
What Are Common Syphilis Symptoms?
Around half of syphilis infections run their course without symptoms, and in one in three people affected, it cures itself after a few years.
In other cases, people affected by the disease experience various symptoms and discomfort. Syphilis symptoms affect the skin, mucous membranes, lymph nodes, eyes, liver, spleen and kidneys, bones and joints, as well as the heart and nervous system if syphilis is not treated.
Common syphilis symptoms include:[3, 6]
- Nodules or ulcers in the genital area, anal canal, or oral cavity
- Swollen lymph nodes
- Rashes on the hands and feet
- Fever, headache, and pain in the limbs
- Diseases of the heart, brain, and nervous system
Where does the term "syphilis" come from? In the 16th century, the physician Girolamo Fracastoro used the word "syphilis" for the first time in a medical teaching poem. In Greek mythology, syphilus was a shepherd whom the god Apollo punished with a disease whose symptoms were similar to those of syphilis.
How Long Can You Have Syphilis Without Knowing?
After infection, it takes an average of two to three weeks for the disease to break out. In some cases, however, the incubation period can be up to three months.
If syphilis is not treated, the disease progresses in three different stages:
- Primary syphilis (two to three weeks after infection)
- Secondary syphilis (about four to ten weeks after infection)
- Tertiary syphilis (after a latent period of many years and without treatment – rare today)
There can be a latent phase between these three stages. This phase can last for years, during which time those affected are symptom-free.
Syphilis Symptoms: What Are the Three Stages of Syphilis?
After contracting syphilis, a red nodule (papule) – called a hard chancre – develops at the site of entry to the body. The chancre is the size of a lentil to a cent and quickly develops into an ulcer that is usually not painful. The ulcer is yellowish and, when opened, secretes a clear secretion that contains many syphilis bacteria and is therefore very infectious. The lymph nodes are firm, slightly enlarged, and not sensitive to pressure.
A hard chancre can be found on any part of the body, but is commonly found:
- in men: penis, anus, and rectum
- in women: external sexual organ (vulva), cervix, rectum, and perineum
- in men and women: lips, mouth, and throat
After about one month, these syphilis symptoms disappear, even without treatment. Four to eight weeks later, the disease turns into secondary syphilis.[5, 8]
Please note: Even if the ulcer has healed, you need to be treated. This stops the infection and prevents it from progressing to the second phase.
Secondary syphilis is the phase during which the pathogen has spread throughout the body. At the beginning of the secondary phase, fever, fatigue, headache, or joint or muscle pain may occur. The lymph nodes are hard and swollen.
Patchy, non-itchy rashes on the palms of the hands and soles of the feet are typical of this phase. However, the rashes can also appear on other parts of the body (arms, legs, torso).
Other secondary-syphilis symptoms include:
- small skin nodules along the hairline on the forehead and around the beard
- whitish spots between 0.5 and 1 centimeter in size on the back of the neck
- hair loss in small patches
- nodules and around the genital organs and the anus
Some sufferers develop inflammation of the periosteum, inflammation of the iris in the eye, or inflammation of the liver and kidneys. The central nervous system is already affected in the secondary syphilis stage in about 40 percent of those affected; meningitis may occur.
Secondary syphilis lasts about two years without treatment, after which symptoms subside. This is followed by the latent phase of syphilis, during which those affected are symptom-free. The bacterium is still in the body, meaning that those affected are contagious and pregnant women are able to infect their unborn children. In 30 percent of those affected, the disease heals on its own.
After several symptom-free years, the late phase of the disease begins: tertiary syphilis.
During this phase, skin rashes return. They are deep skin lesions and ulcers that can break through to the outside (gummata). Typically, the face, torso, legs, and buttocks are often affected, but the palate, nasal septum, throat and larynx can also be affected. The tissue often dies and leaves deep scars. The palate and nasal septum are destroyed.
If the disease remains untreated, some affected persons develop neurosyphilis (experts also call it quaternary syphilis) 10 to 20 years after infection. The spinal cord and cranial nerves are so severely damaged that there can be a lack of reflexes, impotence, deafness, dizziness, visual disturbances, epileptic seizures, delusions, depression, and dementia. Heart disease may also occur.
How Long Is Syphilis Contagious?
During the primary and secondary phase of the disease, affected persons are infectious – and they are especially infectious during the primary phase. In the tertiary phase, affected persons show serious signs of illness, but are then no longer infectious.
Caution: Even if you do not notice any symptoms or are in a symptom-free phase of the disease, the bacteria are still in your blood. You can still infect other people! If you have already contracted syphilis and been cured, you can become infected again during sex. 
What Is the Most Accurate Test for Syphilis?
To diagnose syphilis, doctors usually do a blood test to check your blood for antibodies to syphilis bacteria. Sometimes, a sample is also taken from a weeping skin ulcer (at the beginning of the disease in the primary stage) and tested for the bacterium.
If you have noticed typical syphilis symptoms, such as a hard chancre on your penis or vagina, a sexual health test in the form of a urine or blood sample could also provide a first indication of syphilis infection or another sexually transmitted disease. Samples taken as part of a syphilis test will be screened for the presence of a Treponema pallidum infection, and you will usually be notified of the results after the sample has been analyzed.
To read more about other sexually transmitted infections – including what the signs of an STI are – head over to our dedicated Health Portal article.
When Is Syphilis Detectable?
Immediately after the first bacteria have entered the bloodstream, the immune system forms antibodies against the pathogens to fight them. The blood test detects the syphilis pathogens from the second to third week until many years after infection.
If your blood test is negative, it is very likely that you do not have syphilis, and no further tests are necessary. However, if you experience recurring syphilis symptoms, your doctor will repeat the blood tests for over eight to ten weeks.
Preventing Syphilis Transmission: How Can I Protect Myself?
Use condoms during sex, especially if you have different sexual partners, is a good initial way to prevent syphilis transmission. However, infection with syphilis cannot be safely ruled out even with safer sex measures because, for example, syphilis ulcers in the mouth can also be transmitted through kissing through touching open wounds.
Therefore, you should test yourself regularly for sexually transmitted infections such as syphilis – especially if you change sex partners frequently. If you have a new partner, make sure that they also get tested regularly.
Every pregnant woman is routinely tested for syphilis with a blood test at the beginning of her pregnancy. If the test is positive, doctors check whether the infection was contracted but has healed or whether there is an acute infection. If so, the pregnant woman is treated with penicillin.
Syphilis Treatment: How Is Syphilis Treated?
When syphilis is diagnosed, doctors usually prescribe the antibiotic penicillin – formerly, mercury was in fact used as a form of syphilis treatment. Affected people must take penicillin for at least ten days in a row to safely destroy the pathogen. Penicillin is prescribed for all stages of the disease and can safely cure syphilis. After treatment, doctors carry out regular blood checks to ensure that there is no relapse.
In addition, the sexual partners of those affected should be examined and treated, if necessary – namely, all partners within
- the last three months in the case of primary syphilis, and
- the last year in the case of secondary syphilis.
Please note: You should refrain from all sexual activity during your syphilis treatment.
How deadly is syphilis? Syphilis can actually kill you: One in four people with syphilis will suffer lifelong physical damage from the disease, and one in ten will die from it if they don’t receive treatment.
Common Syphilis Symptoms – at a Glance
What Is Syphilis?
Syphilis is a venereal disease caused by the bacterium Treponema pallidum. The pathogen is transmitted by infected people mostly during sex via the mucous membranes of the penis, vagina, mouth or anus.
Who Is Most Likely to Get Syphilis?
Syphilis most frequently affects sexually active people between 15 and 49 years of age, especially men who have sex with men (MSM). Sex workers, people who frequently change their sexual partners, and HIV-positive people also have an increased risk of syphilis.
What Are Common Syphilis Symptoms?
About half of all those affected do not notice any syphilis symptoms at all. Others have symptoms such as nodules or ulcers in the genital area, anal canal or oral cavity; swollen lymph nodes; skin rashes on the hands and feet; as well as fever, headaches, and pain in the limbs.
If syphilis is not treated, the person may later be affected by heart, brain, and nervous system diseases.
How Can I Protect Myself from Syphilis Transmission?
Use condoms during sex and get tested regularly for sexually transmitted dinfections such as syphilis, especially if you change sex partners frequently. Even if you have already had syphilis and are cured, you can still get infected again during sex.
How Is Syphilis Diagnosed and Treated?
Syphilis can be detected by taking a blood test. Sometimes doctors also take a sample from a weeping skin ulcer and examine it for the pathogen.
Syphilis is treated with penicillin. This antibiotic is prescribed for all stages of the disease and can safely cure syphilis. After this form of syphilis treatment, regular blood tests are necessary.
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