[Question #3074] Syphilis

38 months ago
Dear Doctors, 

I had a low risk heterosexual  encounter, but I got really afraid that I got syphilis.
So just 3 days after the exposure I took 2g of azythromycin in one dose.
Now I am afraid that I took the antibiotic too early and that syphilis may have not been eradicated.
The reason is that azythromycin is a bacteriostatic antibiotic and therefore it only stops replication of the microbe and does not kill it.  If I understand correctly, when bacteriostatic antibiotics are taken, the body must cooperate with the antibiotic and the body is the one eventually killing the microbe. 
If it was too early, could the my body have failed to identify the existence of the syphilis microbe and therefore have failed to destroy the microbe (since it did not identify the infection)?
Are there any studies confirming that syphilis is eradicated when the antibiotic is taken so shortly after exposure?

I also read that syphilis is transmitted when mucous membrane come in contact with open/broken/damaged skin? Does this mean that there must be a cut in the skin?  What is the exact meaning of broken/damged skin?

thanks

H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
38 months ago
Welcome back to the forum, but sorry to see you found it necessary.

It is correct that azithromycin may not prevent syphilis, but not for the reasons you state. Some syphilis bacteria are resistant to azithromycin, in which case no dose will prevent or effectively treat it. The likelihood of azithromycin-resistant syphilis is geographically variable -- for example, it's a very common issue in parts of Europe and the west coast of North America, but is very rare in Africa. If I recall correctly from a past question, you may be in southern Europe (Greece?); I cannot say how common this is there. In any case, if azithromycin resistant syphilis is not common in your area, the timing of taking the drug makes absolutely no difference. There is no such thing as taking the drug too soon. The amount of azithromycin you took is fine; if you were exposed it would be effective. (Bacteriostatic vs bactericidal makes no difference.)

Beyond that, I cannot comment on the risk of the encounter. You don't say enough about your geographic location, your partner and her potential risk for syphilis (e.g. sex worker? otherwise high risk?), or the details of the sexual exposure. Also how long it has been since exposure and what symptoms you have had, if any. As for "open/broken/damaged skin", this makes little difference. Such problems probably increase syphilis risk, but plenty of people get syphilis without such problems.

If you would like to tell me more about the exposure event, I may have more to say. But from what you have said so far, it is very unlikely you acquired syphilis and the azithromycin may have been effective in preventing it.

HHH, MD



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38 months ago
Thank you for your answer. 
You are correct that I live in Greece. 
Please allow me one more question.
During the past, after a similar sexual exposure, I took some  voltaren pills (diclofenac) in order to treat an injury an ankle strain. Εxposure and injury had absolutely no relation, they just took place within the same month.
Is there any data that diclofenac may treat early syphilis?


H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
38 months ago
Only antibioitics (and not even all antibiotics) have any effect on syphilis. No other medications of any kind, including diclofenac (or any other anti-inflammatory drug), have any effect.

Because you refuse to describe your current syphilis exposure, and previously asked previous questions about exposures that obviously carried no risk for HIV, hepatitis, or STDs, I have to assume your current exposure was very low risk or perhaps no risk at all. If you believe it was high risk, see a doctor or clinic about treatment with benzathine penicillin, which is the only recomemmended drug to prevent syphilis after exposure; and/or have a blood test for syphilis after a few weeks have passed.

This and your other questions show you are abnormally fearful of STDs. We cannot help with such concerns, and you can be confident that future replies will repeat the same sort of advice you have already had. Therefore, similar questions in the future will be deleted without reply and without refund of the posting fee. This policy is based on compassion, not criticism, and is designed to reduce temptations to keep paying for questions with obvious answers. In addition, experience shows that continued answers tend to prolong users' anxieties rather than reducing them. Finally, such questions have little educational value for other users, one of the forum's main purposes. Thank you for your understanding.

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38 months ago
Dear doctor,
Please allow me one final question.
As per the studies, vdrl has 25% chances of being false negative during primary stage.
Do you agree with the above, or has the test improved?
thanks
38 months ago
to be more specific. can a vdrl test taken 6 or 8 weeks ater exposure be false negative?
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
38 months ago
The statistic is about right, a quarter of persons with primary syphilis having negative RPR (or VDRL) test. This is an interesting and important question that often is confusing to persons with syphilis or at risk. It's also an excellent example of how a seemingly simple statistic isn't necessarily easy to apply to any particular patient. Thank you for the opportunity to clarify this; it's actually quite simple.

Untreated primary syphilis typically lasts 3-4 weeks, from onset of the chancre (syphilitic sore), usually 10-20 days after exposure, until it heals. The RPR is increasingly positive during that time. In patients with primary syphilis only 2-3 days duration, RPR is positive in less than half. By the time the chancre clears up, it's 100%. If you average everybody with primary syphilis, depending on when they are tested, about 25% have negative results. All those are in patients tested earlier than 2-3 weeks after exposure. Everybody with new syphilis has a positive RPR by 6 weeks. The test is exactly the same:  there has been no difference in RPR test performance over the decades (although additional new tests have been developed and are often used for intiial testing.)

In asymptomatic persons concerned they might have been exposed to syphilis, the RPR and also the newer tests are 100% conclusive by 6 weeks.

That concludes this thread. As noted above, this wil have to be your last one about low risk exposures and your apparent inflated fear of STDs. But I hope this discussion, and the earlier ones, have been helfpul.
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