I have had a RPR syphilis test at 6 weeks after an event that made me very scared of Syphilis. That test was negative and then I went on to have an EIA test at 9 weeks which was negative. I have had no symptoms like a chancre that I’ve seen and I’m a male. I will try not to repeat myself here but I’m getting two small white oval marks on my gums on the same side. It’s 11 weeks after the event and I’m just now seeing them. I just finished a course of 100 MG of doxycycline once per day for 10 days for orchitis.  My main question is if I’m on doxycycline and with the far out chance I had contracted syphilis, these white marks on my mouth couldn’t be from the secondary stage with my antibiotics, correct? How long after a short course of doxycycline could I possibly retest for syphilis without the doxycycline screwing my test. Am I overreacting with two negative blood tests at 6 and 9 weeks? The white marks are not raised on my gums but it is what is making me nervous so please kindly advise. Thank you. 

On a side note as well, I went on levofloxacin at 5 weeks after exposure but I’ve heard that does nothing for Syphilis and cannot affect tests.

Welcome back to the Forum although it saddens me to see that you have felt the need to return.  We covered many of your current questions in our exchange two days ago.  The answers are not going to change.  As I indicated before you need to believe your test results.  The EIA tests are, if anything, MORE sensitive than the RPR and had you acquired syphilis during your exposure of concern your test would have been positive.  ---

Great thanks Dr. Hook. You’ve been a big help. I was tested a day after taking Doxycycline for 10 days which was 11 weeks (77 days) after my exposure. My RPR was negative. I still have a white mark in my mouth that’s been there for 2 weeks and showed up around 70 days after my exposure but based off your feedback, I can put syphilis to rest? 

Absolutely.  The white spot you have noted is NOT syphilis.  It is due to something else.  EWH---

Good Morning Doctor Hook and happy Monday. Since I’m sensitive on this issue, I took a Syphilis EIA test at exactly 90 days post exposure. It was negative. My only question is that I had taken the 90 day EIA test 13 days after my completion of Doxy (100 MG once per day, 10 days). The doxy treatment for something unrelated ending 77 days post exposure wouldn’t delay syphilis antibodies at day 90 and cause my EIA test to be falsely negative would it?

final response.  if you had acquired syphilis, your EIA test would have been positive. Once again, I urge you to believe your test results.  You have been tested using two different, unrelated test types, both of which perform well for syphilis diagnosis.  If you had acquired syphilis your tests would be positve.  YOU DO NOT HAVE SYPHILIS.---