[Question #6898] Syphillis risk?

9 months ago
I am a gay man who has sex with men.  In the last 12 months, I have had two sexual exposures.  On February 3rd, I had unprotected anal sex with another man (the only time literally in my life I have had sex without a condom - I'm still kicking myself for that decision).  On March 2nd, I masturbated with another man and there was lots of body contact with pre-ejaculate.  There was little or no cross-person contact with ejaculate.

On March 19th (approximately 50 days after the initial exposure and 16 days after the first -  and despite being symptom free), I was tested for HIV (4th gen), gonorrhea, chlamydia, and syphillis (RPR).  All tests were negative except chlamydia.  I completed a 1g dose of azithromycin the following day.

On April 29th, a small bump appeared where my scrotum transitions to my perineum.  About 5mm round. Slightly hard.  No pain or itching - just an odd bump.  Just for reference toward what I'm noticing - I've had a very similar small bump on the base of my neck for years.  Since my neck doesn't catch STDs, I've never worried about it except avoiding it with the razor when I shave ;)

On April 30th (approximately 90 days after the initial exposure and about 55 days after the second exposure), I re-tested for HIV (4th gen), gonorrhea, chlamydia, and syphillis (RPR).  All tests were negative.  (I had planned to only be tested for chlamydia because I believed the first tests to be conclusive on everything else, and I just needed proof of cure for the chlamydia treatment - but the appearance of the bump caused some anxiety - so I went ahead and went all in on the testing again).

I know this forum has a large international audience, so to be clear, all the tests were performed by CLIA labs in the US - name brands you would recognize.

Do you recommend any further testing or monitoring?  Is the bump on my scrotum/perineum something I need to follow up on, or just part of aging (I'm coming up on 50)?

Edward W. Hook M.D.
Edward W. Hook M.D.
9 months ago

Welcome to our Forum and thanks for your question.  Your comment about your next not catching STIs brought a smile to my face although you'd be surprised at some of the things I've seen :). In answer to your question however, you are in the clear- no risk that a future syphilis (or HIV for that matter) test will become positive related to the exposures you describe.  To elaborate and provide some additional information which I hope will be helpful:

1.  Syphilis is transmitted sexually only by direct contact.  Thus realistically your February 3rd encounter was your only real risk for syphilis or HIV.  Mutual masturbation, even when there is lots of contact with a partner's genital secretions is not associated with risk for STIs including HIV and even the CDC which tends to be quite conservative, classifies mutual masturbation as a no risk event.  While I suppose that, theoretically if a partner has a syphilis lesion  transmission might occur, in over 35 years or STI-focused practice neither of us has seen such a case. 

2.  While the very conservative recommendations for syphilis testing suggest that persons might develop a positive syphilis blood test, in practice virtually all blood tests become positive by 30 days and certainly by 6 weeks (42 days).

I see no need for further testing or monitoring for syphilis, HIV, gonorrhea or chlamydia.  There is an outside chance that the perineal bump you have discovered could be a genital wart - the timing is about right.  Warts however a mostly a nuisance and do not jeopardize your health.  My advice would be at some convenient time in the future you have a trained clinician take a look.  If it is a wart it is easily treated.

I hope this information is helpful.  If there are further questions please use your up to two follow-up questions for clarification.  EWH

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9 months ago
Thanks for your prompt reply, Dr. Hook.  And thanks for this service - it's quite convenient and reassuring to get facts from experts this way and the ability to wait a few days before asking a follow-up question is really nice - even with minor results from annual physicals with my GP, I often think of questions I wish I had asked in the days after.

This is likely a case of letting the internet get the best of me in the wrong ways, but in my reading online about syphilis RPR tests, some sources say that consuming alcohol in the 24 hours before the blood draw can cause a false negative.  I find it odd that the CDC doesn't mention this, nor do the testing labs (who thoughtfully remind you not to urinate for an hour and to clean your penis before giving a urine sample - it seems they would mention this if there were actual data behind it).

I gave the blood sample in early afternoon and certainly hadn't had alcohol since the evening before - but it's likely I did drink the evening before (I don't exactly keep a drinking journal...but virtual happy hours have become common during COVID).

Is there any data behind the concern around alcohol consumption influencing the syphilis test?
Edward W. Hook M.D.
Edward W. Hook M.D.
9 months ago
Thanks for your follow up question. As you suggest, this is a glowing example of how misstatements present on the Internet can fuel unnecessary concerns.  Blood tests for syphilis detect antibodies to the bacteria that causes the infection, treponema pallidum. While years of chronic alcohol abuse can lead to ill health and reduce an individual’s ability to produce antibodies in some but not even most cases, there is no biological or bio chemical reason that recent alcohol ingestion should have any impact whatsoeverThe results of Syphilis testing.  Please don’t worry that having had a drink the night before having your Syphilis blood test may have created a false negative test result.  EWH---