Why Did My TPHA Titer Skyrocket After Syphilis Treatment?

Q: Why Did My TPHA Titer Skyrocket After Syphilis Treatment?

Hello： Please follow the treatment guidelines from the Infectious Disease or Urology departments, and schedule a follow-up in three months. <br>The hospital physicians are adhering to medical guidelines, which is consistent globally. <br>As for why the levels may be elevated, it

Why does the titer of Treponema pallidum hemagglutination assay (TPHA or TPPA) increase sharply after treatment for syphilis?

Hello Doctor: I couldn't find relevant information while searching online, so I would appreciate it if you could take some time to help answer my questions.
Thank you again for your assistance.
Recently, I went to the hospital for a syphilis test, and the result came back positive.
The doctor diagnosed me with secondary syphilis because I had small red spots the size of soybeans on my palms and soles.
However, there were no ulcer symptoms around my genital area (I had undressed for a thorough examination by the doctor).
The doctor then prescribed one injection of Bicillin L.A.
penicillin and sent me to the injection room.
He also ordered blood tests for RPR, TPHA, and HIV, and told me to return in three months for another blood test (Oh my, three months? That seems too long!).

A few days later, I used the hospital's online system to request my personal medical records, including the test results.
I saw that before I received the Bicillin L.A.
injection, my blood test results were: RPR: REACTIVE 512 DIL, TPHA: REACTIVE >1:5120, HIV: (-) Non-reactive.
After a week, I went to a urology clinic where the doctor prescribed Doxycycline 100 mg, instructing me to take one pill twice a day for 14 days.
Alternatively, he offered Azithromycin 250 mg (Zithromax), which comes in a box of six pills, and advised me to buy two boxes to take eight pills at once.
He mentioned that Bicillin L.A.
penicillin is only available at large hospitals, which is why the clinic only prescribes oral medications.

I was puzzled about whether taking eight Azithromycin 250 mg pills at once could effectively treat syphilis.
Therefore, I chose to take Doxycycline 100 mg, one pill in the morning and one in the evening for 14 days.
After completing the 14 days (two weeks), on the 16th day, I went to a private medical laboratory for blood tests, this time also including an HIV test.
This laboratory is quite large and has multiple branches.
The blood test results were as follows: STS (RPR): REACTIVE 1:16, TPHA (TPPA): REACTIVE >20480X (POS), HIV (Type 1/2/0): Non-reactive.

Seeing the report made me very anxious, so I would like to ask you a question: I have already received the injection and taken Doxycycline 100 mg, so why is my TPHA (TPPA) result even higher than the one from the hospital? And it’s alarmingly high? Is it because I had too few injections? My friends have received several injections; why did the physician at the medical center say that one injection is sufficient for secondary syphilis? What should I do now? Is it because I only received one injection? Or could it be that by taking Doxycycline 100 mg twice a day for 14 days, I completely counteracted the effect of the Bicillin L.A.
penicillin, resulting in a TPHA (TPPA) value that is even higher than the one from the hospital? Thank you very much.

Ding Shiyuan, 30~39 year old female. Ask Date: 2017/11/27

Dr. Du Shixi reply Urology

Hello: Please follow the treatment guidelines from the Infectious Disease or Urology departments, and schedule a follow-up in three months.
The hospital physicians are adhering to medical guidelines, which is consistent globally.
As for why the levels may be elevated, it can be said that without treatment, they could rise even higher.
It takes time for the levels to improve with treatment.
If you are not receiving treatment at a hospital, it is advisable to have follow-ups at a single, consistent hospital.

Reply Date: 2017/11/27

More Info

The situation you are describing regarding your syphilis treatment and the unexpected rise in your TPHA (Treponema pallidum hemagglutination assay) titer is indeed concerning and warrants a thorough understanding of the dynamics of syphilis treatment and serological testing.

First, it is important to clarify that TPHA is a treponemal test used to detect antibodies to Treponema pallidum, the bacterium that causes syphilis. Unlike non-treponemal tests such as RPR (Rapid Plasma Reagin), which measure the presence of antibodies that may decline after successful treatment, treponemal tests like TPHA remain positive for a long time, often for life, even after successful treatment. This means that a high TPHA titer does not necessarily indicate active infection or treatment failure; it may simply reflect a historical infection.

In your case, you were diagnosed with secondary syphilis, which is characterized by systemic symptoms and skin manifestations. The treatment you received, Bicillin L.A (benzathine penicillin G), is the standard and recommended treatment for syphilis, especially for early stages. The typical regimen for secondary syphilis is a single intramuscular injection of benzathine penicillin G, which is effective in clearing the infection.

The rise in your TPHA titer after treatment could be attributed to several factors:
1. Natural Variation: Serological tests can show variability due to biological factors. The immune response can fluctuate, and the timing of the test relative to treatment can influence results.

2. Timing of Testing: If the TPHA test was performed too soon after treatment, it might not accurately reflect the effectiveness of the therapy. Antibody levels can take time to stabilize after treatment.

3. Doxycycline Use: While doxycycline is an alternative treatment for syphilis, it is generally not the first-line treatment for secondary syphilis. However, taking doxycycline after receiving benzathine penicillin should not negate the effects of the penicillin. The concern about "antagonizing" the treatment is not typically supported by clinical evidence, as both antibiotics work differently and do not interfere with each other in a way that would prevent the penicillin from being effective.

4. Re-infection: If there was any exposure to syphilis after treatment, this could lead to a rise in titers. It is crucial to ensure that sexual partners are also tested and treated if necessary.

5. Laboratory Variability: Different laboratories may have variations in their testing methods and reference ranges, which can lead to discrepancies in results.

Given your situation, it is essential to follow up with your healthcare provider. They may recommend re-testing after a certain period to monitor your RPR and TPHA titers. If your RPR shows a significant decline, it would indicate that the treatment was effective, even if the TPHA remains high.

In summary, while it is understandable to be anxious about the rise in your TPHA titer, it is crucial to remember that treponemal tests can remain positive long after successful treatment. The best course of action is to maintain open communication with your healthcare provider, adhere to follow-up appointments, and ensure that any potential re-exposure to syphilis is addressed. Your healthcare provider can provide the most accurate guidance based on your specific medical history and test results.

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