Is an RPR or FTA-ABS re-test necessary?

[slartibartfast]

Hello,

I am a male and just over seven months ago I had a sexual encounter with a female escort on a trip to Germany (this is NOT a common occurance - happened only once before in my life, and after all the obsessing related to this encounter I don't see it happening again!). A condom was used for intercourse, but not for receptive oral sex (or, obviously, for kissing). I did not perform oral sex during the encounter. When the encounter occurred I was half way through a 3 week course of Ciproflaxin for a completely unrelated case of prostatis (so I had a week and a half of antibiotics after the encounter). About a week after I returned from Germany I had a canker sore inside my mouth just at the base of my gums (so right at the border between hard and soft tissue). This is not unusual after coming back from a sleep deprived international trip (I get them about 25% of the time when I come back from a long haul trip). This looked just like a standard canker (white, flat, and with a red inflammed border), hurt just like one, and was gone in the same amount of time. I had no sores anywhere else on my genitals or lips (and I did look thoroughly and frequently). Still, it spooked me a bit even though it looked no different (and felt no different) than any canker sore I had in the past. None the less, six months after the encounter I got an RPR and HIV test. Both came back negative. Now, about a week after the test I started to get small, raised, red dots on my knuckles and at the base of several of my fingers - some were clustered; they were no where else on my body and there was no other "rash". I should add that this followed a several week period of long runs during which I wore fleece gloves that left my hands damp itchy and ended up creating exema-like cracked knuckles and skin that persisted until I stopped wearing the gloves. Obviously, these red dots spooked me again and made me think of secondary syphilis. My question has three parts:
1.) Could the fact that I was on antibiotics have interrupted the course of syphilis and prevented a chancre or impacted the RPR results 5 1/2 months after I finished the antibiotics? How accurate would the result be 6 months later assuming a normal progression?
2.) Would you recommend a re-test for the RPR and an additional test (FTA-ABS) as well to be sure?
3.) If I had a flu-shot a month ago and just got over an upper respitory cold, how long should I wait to get re-tested (if I need to) in order to avoid a false positive result?

Thank you for your reply.

[H. Hunter Handsfield, M.D.]

Syphilis is rare in this situation; a typical canker sore (painful) is unlikely to be a syphilitic chancre (painless); and the negative RPR 6 months after the event is proof you don't have syphilis.  Cipro is totally inactive against syphilis and could not have affected the test result, and neither can a flu shot.  I don't know the cause of the "red dots" on your knuckles, but it isn't syphilis.  You don't need further testing.

Forget syphilis.  See a health care provider if you remain concerned about the red spots.

Good luck--  HHH, MD

[slartibartfast]

Doctor,

Thanks for the rapid and very helpful answer. Off to my dermatologist to get the red dots figured out.

Very much appreciated the assistance.