[Question #5104] Syphilis transmission question

24 months ago
What are the chances of getting syphilis from performing cunnilingus on a woman who has it? I have read various sources saying that the only conceivable risk from cunnilingus is HSV-1, but I've also seen syphilis included in this list. Would it be more or less likely than HSV-1 transmission? Also, does it pose less of a risk than performing oral on a man who has it? Thank you.
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
24 months ago
Welcome to the forum. I happened to be online when your question popped up. Most users should not expect nearly real time replies!

Syphilis definitely can be transmitted by oral-genital contact, including cunnilingus. However, the chance is very low for any single exposure. First, it is unlikely any particular sexually active woman has syphilis. (The large majority of cases in industrialized countries are in gay men.) Second, even if a woman has syphilis, the chance of an infectious lesion (rash, sore, etc) in the genital area is very low. Unless you know for sure that your cunnilingus partner has syphilis, or is at particular risk for it (e.g. the partner of a guy known to have syphilis), there is no need for syphilis testing and this event is nothing to worry about.

There is little no risk of HSV1 by performing cunnilingus on a woman with herpes. HSV2 could be a risk if the woman has genital herpes. That risk probably is higher than for syphilis, but still extremely low.

Finallly, you are right to ask about performing oral sex on a man with syphilis, especially if the oral partner is also male. That's because, as noted above, most syphilis occurs in men who have sex with men. Still, even among MSM, oral sex is less risky than than anal sex.

If you wouid like to provide more information about your partner(s) and why syphilis in particular is on your mind, I might have more to say about it. In the meantime, I hope this information is helpful.

HHH, MD
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24 months ago
Thank you, that was much faster than expected! 

The reason I asked is that I performed cunnilingus on a CSW. I got tested after the event, but it was not late enough to cover syphilis and, but I am not worried about HIV at all. I just wanted to know if I should bother to get re-tested 6 weeks after the event given my history. I did notice what looked like a classic canker sore on my lower lip a few weeks after the event. It wasn't painful, but it didn't look like a chancre either (not indurated), and I have a history of getting canker sores sometimes.
24 months ago
Also, not sure if it matters, but the CSW was from china and definitely not "high end".
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
24 months ago
I'm not sure I understand the timing of the sexual event, the canker-like sore, and your negative syphilis test. For the reasons above, syphilis is unlikely. But it would make sense to have another syphilis blood test 6 weeks (or more) after the sexual contact. If negative, it will prove conclusively you did not catch syphilis-- assuming, of course, no potential exposures after that.---
24 months ago
Thanks. I will report back with the results. The test occurred 18 days after exposure, and the canker sore occurred a few days after the test.
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
24 months ago
That means the canker started at least 3 weeks after the exposure? While it can take that long for a chancre to appear, it's unusual.

Normally threads are closed after two follow-up comments and replies, but I'll leave it open until you report your repeat syphilis blood test result (or 4 weeks max, whichever comes first). I won't have any further comments or advice until then.
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24 months ago
So I went and got tested immediately, and the results are negative. This is now 12 weeks after the exposure, so I’m guessing that’s totally conclusive?

Yes the canker sore occuree about 3 weeks after. It also healed in a few days. Thank you.
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
24 months ago
Thanks for the follow-up and happy to hear your test was negative. At 12 weeks it definitely is conclusive.

That concludes this thread. I hope the discussion has been helpful.
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