[Question #5243] Positive RPR but negative T.palladium

22 months ago
Hi , I had just gotten through asking Dr. Hansfield some questions regarding risk from exposure and HSV. All my questions were answered. However as I had mentioned, I had STD testing done and after the last thread was closed I got new results back from Planned Parenthood that indicated my RPR was positive but the Treponema palladum was negative. I got these results on their portal and their clinic is closed until Tuesday so no one can interpret them for me until then. From what I read online, I don’t believe I have syphillus but am concerned as to why the RPR was positive. I tested negative for HIV that day. One site said it could be positive from an acute bacterial or viral infection. Could it be positive due to a new HSV infection? As I mentioned in last post since I saw physician at PP she did not feel as though my symptoms looked like HSV but since then I have delevoped two lesions different from what I had the week prior that are painful.  So still paranoid about that and about why the RPR was positive. 


Edward W. Hook M.D.
Edward W. Hook M.D.
22 months ago
Welcome back to the Forum.  Our replies to clients are closed following a total of three replies.  On this occasion, I'll be addressing your new questions.  

When an RPR test is positive but the treponemal test is negative, the results are considered to be falsely positive.  The RPR test and treponemal tests measure different types of antibodies and when persons have syphilis they make both types of antibodies.  On the other hand, a small proportion of people who do not have syphilis make antibodies which are positive on one test of another on the basis of chance alone - you appear to be one of those people.  Persons make antibodies which give false positive antibody results on the basis of chance alone although the frequency of this phenomenon is also a little bit higher among persons who have chronic inflammatory diseases such as rheumatoid arthritis or lupus, or in persons who are reacting to a recently acquired viral diseases (not necessarily herpes).  In most people with these false positive results however there is no obvious reason or associated process to explain the false positive test result.  

In your case, with the continued appearance of new  lesions, I would advise you to seek further evaluation.  The new lesions would be the clue that might help.  I suggest you return to PPH on Tuesday when they open.

I hope this is helpful.  As with your last thread, if there are further questions you now have two additional follow-ups to seek clarification.  EWH
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22 months ago
-So, how often do you see a positive RPR when someone newly acquires HSV?
-And does the fact that the titer said 1:1 make a difference ?  From what I understand that is low? 
-do you often see HSV lesions not be blisters, nor on a red base and but look more like pimples and that are spread out?  Two I popped and they havent created ulcers or anything- just a red mark/bump? Especially if this is a primary infection? 
Edward W. Hook M.D.
Edward W. Hook M.D.
22 months ago
You are asking good, but difficult to answer questions.  There is not precise data to answer some of these questions which is part of the reason I have encouraged you to seek further evaluation.  While I do not have the opportunity to examine you or to order tests, I'll describe my sense.  These lesions could be HSV which can occur with a non-classical presentation (i.e. rather that presenting with small painful "water-blisters" it can be with bumps or other sorts of rashes).  The only way to be really sure is to have a PCR test performed on a lesion and even then, while a positive test can be diagnostic negative tests can occasionally occur in persons who do have the infection.  In answer to your follow-up questions:

1. So, how often do you see a positive RPR when someone newly acquires HSV?
This is a question that does not have a precise answer. Most people with new HSV infections do NOT have false positive RPR tests.  I would guess the proportion who do is less than 3 or 4%.

2.  And does the fact that the titer said 1:1 make a difference ?  From what I understand that is low?
A 1:1 is the lowest possible positive RPR result.  Most false positive tests are low.

3.  do you often see HSV lesions not be blisters, nor on a red base and but look more like pimples and that are spread out?  Two I popped and they havent created ulcers or anything- just a red mark/bump? Especially if this is a primary infection?
See my comment above.  It certainly is not uncommon for the infection to appear without blisters.  How often again is hard to say.

Finally, PLEASE do NOT  squeeze or pop these lesions.  The manipulation can change the appearance and lead to infection due to skin bacterial  

I hope this helps.  I know you are concerned and worried.  You need to be seen by someone who know what they are doing or at least someone who has access to PCR tests for herpes diagnosis (all too often this is NOT what you will get in an ED or walk-in Clinic).    If not PPH, perhaps your local public health STD Clinic or a good dermatologist may be helpful.  EWH
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