[Question #4827] Interpreting syphilis results

27 months ago
Thank you in advance for your help. In mid-Nov, I noticed a "lesion" on my pointer finger on the dorsal side between the knuckles.  It was circular and about 6mm diameter.  It was hard, almost callus-like, with a raised rough border and slightly concave (scooped-out) interior.  No blood, no pain. In the month prior to its appearance, I'd had hookups with two male partners (I'm male) that included substantial insertive fingering of their butts. I didn't seriously consider the idea of syphilis until the lesion started quickly shrinking away, which didn't seem like a callus. Within 4 weeks of noticing it, it was essentially gone. I decided to get a syphilis test.

- First testing was done 5 weeks after the most recent potential exposure. The lesion was almost entirely gone.  Results: EIA and FTA both negative.
- Given the uncertainty of early testing, I went to get tested again 3.5 weeks later.  This was now at least 8.5 weeks since possible exposure, and roughly a month since lesion disappeared.  Different algorithm used.  Results: RPR and TPHA negative.

I'm grateful for these results, but given the complexity of syph. testing, I wanted to check in about their conclusiveness. I appreciate your thoughts on these questions:

- With the time frames and tests I have described, can I consider myself 100% syphilis-free, or should I do a follow-up, and when?
- I wonder with what degree of frequency you may have encountered syph. infections on the fingers?
- A bit of a silly question, but anyway: given the unusual (non-mucosal) location of the lesion, would this affect how long it'd take for a potential syph. infection to show in results? I'll also mention, there was plenty of contact between the lesion and my eyes, because of rubbing with that part of finger. And I've noticed increased teary-ness lately.  Would finger/eye infections be detected equally by these tests? Thx.
Edward W. Hook M.D.
Edward W. Hook M.D.
27 months ago
Welcome back to the Forum. Thanks for your question and your detailed description of your lesion and test results.   Syphilis can occur on the finger and I have seen a very few cases from exposures of the sort you describe.  Having said that, I can confidently assure you that the lesion you had was not syphilis.  Had it been, your blood test would have been positive by the time the lesion was resolving.  While syphilis blood tests can be negative when lesions are present, if the lesion is resolving, and the blood test is negative, the lesion is NOT syphilis.  

Transmission of syphilis from the fingers to the eyes in the manner you describe is not something I have ever seen or heard or and it is not something I would worry about, even from a theoretical perspective.

I hope this information is helpful. EWH
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27 months ago
Thank you very much for your reply. That is reassuring. Just to clarify, regardless of it being a finger lesion or a more typical genital lesion, the blood tests would respond the same way?

I anticipate a "yes" to that. :) So I'll move on to my main "follow-up". Given the proximity between the two random sexual encounters with significant fingering, and then 2-3 weeks later, developing this lesion, I wonder if there is anything else I should be concerned that it could be? I ask for a few reasons.  1) I've never seen such a lesion on my finger.  2) Considering its resemblance to the syphilis chancres I've seen in pics, I wonder if it could be the early symptom of another disease process (whether bacterial or viral).  And 3), frankly the life cycle of syphilis freaks me out, with its ability to go "stealth" for awhile and slowly injure your brain, vision, etc.  I'd hate to dismiss this and only realize later it was something else. So... granuloma inguinale? Any other ideas?  Would you suggest anything else to be checked for?

For thoroughness, only other unusual symptoms: I tore a side muscle and developed plantar fasciitis within 1-2 wks of the lesion resolving, doing physical activities that were part of my usual routine (gym, running). I mentioned before that my eyes have been teary, but that could just be for the cold. Thanks again.
Edward W. Hook M.D.
Edward W. Hook M.D.
27 months ago
Correct, no matter where the lesion might appear, your blood test results have told the story- this was not syphilis.

s far as other STIs that might have caused this lesion, there are no STIs to be concerned about.  Nothing here suggests herpes, the ulcer of LGV is transient and does not have this appearance and there are almost no cases of granuloma inguinale in the U.S. or western Europe and once again, the description and time course of the lesion do not suggest this.  While I do not have a good alternate explanation for what he lesion you noted might be, I am confident it was not an STI.

I hope these additional comments are helpful.  EWH
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27 months ago
Thank you very much for this additional info. I consider this my due diligence, since I don't want to overlook something important.

I have a photo of the lesion, so perhaps I'll visit the dermatologist and ask his/her opinion of what else it could have been.

With regards to LGV, I see that it is a form of chlamydia.  I take your point that this does not sound like it, but out of curiosity: at the same time when I got the first tests for syphilis (5-6 weeks after potential exposure, as lesion was almost entirely healed), I received a chlamydia blood test as well (negative).  As far as testing for LGV goes, would such a test, at such a time, have detected it?

Finally... you mention that you feel confident this was not an STD.  If I may elaborate on that point a moment... given that there's feces in that region, and this always implies potential bacteria present, is it possible I was exposed to something in that way?  Something not particularly specific but still infectious?  Or are infections more known, categorized, and limited than the sort of phenomenon I'm describing?

And thank you again for your specific help and for offering this great service.
Edward W. Hook M.D.
Edward W. Hook M.D.
27 months ago
All chlamydial tests currently in use would also detect LGV if present.  LGV is a local infection however so testing would only detect infection at sites tested (i.e. urethra or urine, rectum).  Ulcers due to LGV are transient and sound nothing like the lesion you described. Further, chlamydial infection including LGV are not transmitted or acquired during masturbation/fingering.

Sorry, the lesion you describe would not be the sort of thing that would result from contact with feces.

I see you are having a difficult time accepting that this is not related to the fingering/masturbation you described but it really is not.  I think your idea of discussing with a knowledgeable dermatologist who is also familiar with STIs is probably a good idea as I would hope it would relieve your continuing concern.

As per Forum guidelines, as this is my 3rd reply to these questions, this thread will be closed shortly without further responses.  EWH
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27 months ago
Thank you, Doctor.