Syphilis used to be one of the most common STDs in the world. But with the discovery of Penicillin, the number of cases dropped significantly. However, in the recent years, there have been a steady rise in the number of cases of Syphilis. A news article recently reported a 70% increase in the number of cases in the US from 2015 to 2019.
In Singapore, about 1500 cases of Syphilis have been reported every year for the past few years. That works out to be almost 5 cases every single day.
There were also studies to show an increase in the incidence of Syphilis in people who are on HIV PrEP. In this article, we will discuss the symptoms of Syphilis, how to diagnose it and how to treat it.
What is Syphilis
Syphilis is a Sexually Transmitted Disease (STD) caused by the bacteria – Treponema Pallidum. Known as a “great mimicker”, the signs and symptoms of Syphilis are diverse (and mimic the symptoms of other diseases and illnesses hence the name) and can be very subtle or even not present despite a person being infected. This is why screening for Syphilis, even if you feel completely well, is important.
How is Syphilis transmitted?
Syphilis is transmitted via direct skin contact with infected lesions. Therefore, Syphilis is most infectious when a patient has symptoms. Syphilis cannot be transmitted via sharing food, towels or toilet seats.
What are the symptoms of Syphilis?
The symptoms of Syphilis are divided into 3 stages.
Primary Syphilis
This is characterized by a painless ulcer at the point of infection. This ulcer is called a Chancre. Commonly the ulcer is found on the genitals of around the anus. But it can also occur on the fingers or face. Although this is rare. From when a person is infected, it takes between 9 to 90 days for the ulcer to form. Direct contact with this ulcer can transmit Syphilis.
Because the ulcer is painless and can be in an area that is not easily visible (for example around the anus of in the vagina), it is frequently missed by patients and Doctors.
Even when patients do see it, they may just try to treat it with over the counter creams, not knowing what has caused the ulcer.
The thing is, even without any treatment, the ulcer will heal all on its own. This may give patients the false idea that the problem has gone away or their over the counter cream worked.
But the Syphilis infection is still growing in their body and eventually leads to…..
Secondary Syphilis
This is characterized by a rash all over the body but mostly on the trunk. Because this rash can look like any other rash (even a rash caused by an allergy), it is also commonly misdiagnosed. One unique feature of this rash is that it affects the palms and the soles. Not many rashes do that. The rash can be a little itchy but is never painful. Direct contact with this rash can transmit Syphilis.
This rash usually comes on about 6 weeks after the ulcer has healed.
Even with no treatment, the rash will go away on its own. Again giving the false impression that the problem has been solved. However the Syphilis is still in the body and causing damage. But it goes into a period where there are no symptoms. This is called….
Latent Syphilis
Latent Syphilis is actually a very misleading name. Because there is nothing latent about it. Although during this phase the Syphilis does not show any symptoms at all, it is continuing to cause harm in the body. This is why screening for Syphilis is so important. The latent phase can last for up to 10 years or even longer in some people. But eventually the Syphilis causes enough damage and leads to….
Tertiary Syphilis
This is when the Syphilis has damaged the brain and/or the heart and blood vessels enough to cause symptoms. The symptoms vary greatly from a severe change in personality all the way to ruptures of the aorta causing rapid death.
How do I test or screen for Syphilis?
Just like HIV testing, Syphilis testing also has a window period. That means tests done too soon after a person is infected with Syphilis will not be accurate.
There are 2 types of tests for Syphilis. They are both required to diagnose Syphilis and both play a crucial role.
Treponemal tests
The tests that fall into this category are – Tp Ab, TPHA and TPPA. Basically any test that starts with the letter “T”. Rapid Syphilis tests are also Treponemal tests.
They are the usual initial screening test for Syphilis. They are usually accurate 1 month after infection OR 1 week after appearance of the chancre of Primary Syphilis.
However, a positive “T test” alone is not enough to conclude that a person is infected with Syphilis. If the Treponemal Test is positive, Drs will move on to doing….
Non-Treponemal Tests
The tests that fall into this category are – VDRL, RPR. These are tests for different antibodies that are also related to Syphilis. If these tests are positive also, then we can conclude a person has been infected with Syphilis.
If I have been infected with Syphilis before and have been cured, are these tests still accurate? How do I know if I have been infected again?
The main drawback for Treponemal Tests is that they cannot be used to screen for a Syphilis infection after a person has been infected with Syphilis (even after he/she has been completely cured). This is because a person who has been cured of Syphilis will still have antibodies to Syphilis in the body. So these “T tests” will always be positive. This does NOT mean they have been infected again. This is called a serological scar. That said there are some very lucky people whom the Treponemal tests become negative after about 7 years. But this is rare and you should not count on it.
So for people who have been infected and cured of Syphilis, we have to rely on the Non-Treponemal tests. This is because we can track the level of Syphilis activity in the body by the strength of the reaction of these tests. If you look at a report for a Non-Treponemal test, aside from saying that the test was Reactive (positive) for Syphilis, it will also provide a number. 1:2 or 1:4 or 1:8 etc. Always in multiples of 2. This is what we call the Titer. This tells us the strength of the reaction. The higher the number, the stronger the reaction, the greater the activity of Syphilis in the body. So if a person has been cured of Syphilis and was discharged with a titer of 1:2. And is tested again 1 year later and found to have a titer of 1:16, very likely this person has been re-infected with Syphilis.
How to you cure Syphilis?
Syphilis is actually rather easily cured with Penicillin injections. If a person is allergic to Penicillin or for whatever reason the Penicillin treatment fails there are also other antibiotic options.
The problem here is how much Penicillin do we have to give? This is when we talk about early and late Syphilis.
What is early and late Syphilis?
Early and Late Syphilis is defined simply by time. If a person was infected 1 year of less ago, it is Early Syphilis. If a person was infected more than a year ago, it is Late Syphilis. If the patient cannot be sure, most Doctors would err on the side of caution and assume it is Late Syphilis.
The key difference here is that Early Syphilis only require ONE injection of Penicillin. While Late Syphilis require THREE injections of Penicillin.
OK I have had my Penicillin shot for Syphilis. How do I know I am cured?
Well first of all, if you had any symptoms, this should go away very quickly after the treatment. Doctors would then ask you to come back regularly for Non-Treponemal Blood tests to ensure that the titer falls to a level that we can conclude you have been cured and that the Syphilis does not come back. In Singapore we follow up the patient for 2 years.
More complex questions
What if the Treponemal Tests and Non-Treponemal Tests do not match?
There are many possible reasons why one test is positive while the other test is negative. This should be interpreted by your Doctor in the context of your medical history and physical examination. And your Doctor will advise you on the proper next steps to take. To give you an idea of the possible reasons here is a table:
Why does my doctor say I may still have Syphilis even if my test is Negative?
Do note that a Negative test on both Antibody tests DOES NOT always mean you are free of Syphilis. Because your body takes time to develop the antibodies towards Syphilis that these tests are designed to detect, if you have only recently gotten infected, the both tests may show up as Negative (Scenario 4) even though you do have Syphilis in your system.
A further complication for interpreting the results is that Non-Treponemal Antibodies decrease over time and because a Latent state of Syphilis is from 1 to 40 years, having a test result like Scenario 2 could mean an infection is still present but you were infected long ago ( approximately 10 or more ago).
The last complication also from Scenario 2 is the Prozone effect, this happens when there are TOO MUCH non-treponemal antibodies. This causes the test to read as negative even though you do have a Syphilis infection.
False Positive?
Yes, unfortunately there are situations where patients test positive for Syphilis despite not actually having the disease. Unfortunately certain conditions can confound the tests and lead to a false positive.
These conditions are:
- Pregnancy
- HIV infection
- Autoimmune disease – Rheumatoid Arthritis, Lupus
It is therefore important you inform your doctor if you have any of such conditions when he is interpreting your results.
What else do I need to know?
Syphilis is sexually transmitted. So if you have been diagnosed with a Syphilis infection, you should get screened for the other STDs too.
You should also get screened for HIV. Please click on this link for our article on HIV testing.
Another common STD that causes ulcers in the genital region, mouth and fingers is Herpes. Click here for our article on Herpes.
In Summary
Syphilis can quietly damage your body. You should get screened for it regularly. If you have been infected do not worry, Syphilis can be cured.
If you have been infected with Syphilis, please also screen for other STDs as well as HIV.
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