Am I at risk for developing/tansmitting genital herpes?

[concernednp]

Dr.,
First I would like to thank you for providing such a wonderful service. Four years ago I had an area of vesicles appear on my right knee,and it reoccurs every 3-4 months I have scarring on my knee from these occurences. I have cultured this area for HSV and it was negative. I have had HerpesSelect testing done with results as follows  8/06/07  HSV2 1.26      8/29/07 HSV2 <0.90   3/04/08 HSV2 <0.90    4/30/09 HSV2  1.61  All HSV 1 results were always negative. I had a  HSV Western Blot performed by University of Washington on 5-18-09   with HSV 1 being negative and HSV 2 being positive. I have never had a break out on my genitals (last year I had an area I was suspicious about on my sacrum/coccyx area- it itched and we were at the beach when it started so unsure ? bug bite) but my concern is  am I at risk for breaking out in my genital area and/or transmitting this to my partner? Is this a low or high probability? Do I need to be on daily antiviral therapy for not only myself but my partner ( I don't really want to take this if I don't need to)? When I have a break out on my knee it does respond to the antiviral therapy very well. This is not the same partner that I was with 4 years ago and we do not use condoms.  Sincerely, concernednp

[Edward W Hook, MD]

There are several unusual elements to your infection that are worthy of comment before I address your concerns directly.  The first is that your outbreaks occur on the knee rather than the genitals.  This is important because herpes infection live in nerve roots and the nerve roots which supply the front of the knee do not overlap with the nerve roots that serve the genitals.  On the other hand, the nerves which supply the back of the knee are the same as the genitals.  This is important because, if your outbreaks occur on the back of your knee there certainly is a possibility that you sometimes have shedding of herpes viruses asymptomatically from your genitals as well.  If the outbreaks are on the front of the knee, this is far less likely.

The second thing surprising about your report is that your HerpeSelect values have been negative to very low positive.  This too is unusual.  

Having made these statements, I find myself thinking that your partner is at low, but not no risk for infection.  Condoms and chronic suppressive therapy would make it most unlikely that you would transmit infection to your partner through sex.  Without them, given the information I have provided above, if the outbreaks are on the front of your knee I would say the risk is low.  On the back of the knee. I would recommend condoms and suppressive therapy (unless of course your partner already has HSV.  In situations such as these, he/she should be tested since the odds are pretty good that he/she, like 20% of American adults will already have HSV-2).

I hope this makes sense.  I realize the answer is a bit complex but so is your circumstance.  EWH

[Vance2335]

You have to pay for a question to be answered, you can not jump on someone else's tread and get your question answered.

[concernednp]

Thank you for the information. The outbreak occurs on the front of my knee. And yes this situation is  different. The dermatome that it appears on is L 3. Thank you so much.
                          Sincerely,
                            concernednp