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HSV2 in the ilioinguinal nerve
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HSV2 in the ilioinguinal nerve

Hi Doctor,

This has partially been discussed before, but not to a great extent. About 5 months ago I contracted HSV2 during protected sex. My primary infection was on the scrotum near the base of the penis on the left side, and on the front interior thigh on the right side. I found it strange that my primary infection was distributed in this manner, and did a little research. What I discovered is that the lumbar L1 nerve (the ilioinguinal nerve) innervates both the anterior scrotal skin and the interior thigh skin, where I got my herpes infection. I have the following questions for you based on this knowledge:

1) Assuming I am only infected in the area identified above, how "at home" is HSV2 in the L1 dermatome/lumbar ganglia? I know it primarily affects the sacral ganglia, and that this is a different dermatome, so is it likely that I will have less recurrences and that it will shed less?

2) Is it possible that I do not shed from my penis (innervated by scrotal nerves), aside from the base (which is innervated by L1)?

3) I've heard HSV doesn't asymptomatically shed from thicker skin, so how much asymptomatic shedding is there from the anterior scrotal skin, the base of the penis, and the interior thigh skin?

4) Since my initial infection, I have been on twice daily Acyclovir 400 mg and have had no recurrences. I'm told that the first six months will be the worst in terms of symptoms -- given this, is there a good chance that as long as I continue on suppression therapy, I am likely to be recurrence free?

5) Given that according to some studies most people asymptomatically shed 5%-10% of the time, and that antivirals reduce asymptomatic shedding by about 90-95%, if I am recurrence free and on suppression therapy, am I only infectious between 0.5% to 1% of the time, or even possibly never infectious?

I know there is not a lot of data about what I am asking you, but I'd just like to get your opinion on what is and isn't possible. Thank you.
I think you're hoping for an opinion that allows you to be less worred about transmitting HSV-2 to future partners by concentrating on those sites with recongized oubreaks.  Sorry, but I don't buy it. From all we know about aymptomatic shedding of the virus and transmission, all peopope with gential (genital) area hepres have to take precautions with all partners, for exposures that involve ANY genital area contact.

Initial herpes usually involves the direclty ivnolved sites, e.g. the penis, labia and vaginal opening, or the anus.  Reucrrent herpes oubreaks, however, often emanate from nearby nervies, resuling in outbreaks on the buttocks, groin, lower abndoman, scrotum, upper thigh, etc.  It can be confusing, becuase the initial ifection may remain asymptomatic, creating the ipression that the infection is limited to the outlying area.

So my best judgment is that your ilioinguinal recurrent outbreaks does not mean your HSV-2 infeciton is limited to that site.  In terms of asymptomatic shedding of the virus that could infect partners, you should assume the virus is directly shed from your penis, not only the scrotum.  Condoms therefore remain important in your strategies to protect future partners.

1) For those reasons, I do not accept these premises.  You need to assume you shed virus from the penis, and perhaps other aread that do not eem to be directly affected by your infetion.

2) That's possible but unlikely.  You should assume penile shedding.

3) There does appear to be a lesser rate of asymptomatic sheddig from thicker than thinner skin, but probably not sufficient difference to rely on a lower transmission risk.

4) Most people on anti-HSV therapy experience reduced frequencies of both symptomatic outbreaks.  But I emphasize "reduced", breathroughs are less common on treatment but they happen.  Being on consistent suppressive therapy reduces but does not eliminate the possibility of transmission to uninfected partners.

5) The effectiveness of antiviral therapy in reducing asymptomatic shedding is not as good as the older figures you cite.  The current, newer data suggest an overall suppression about 505, not 90%.

It is almost impossible accuratley estimate the actual asymptomatic shedding rate in any particular patients.  Even with acyclovir, you should assuke a pottential for transmission at least 5% of the time.  Except for new partners known to have had HSV-2, you are ethically obligated to inform any and all future sex partners of your genital herpes and the possibility they will be infected.

Regards--  HHH, MD
Dr. Hook also glanced at your question and my reply.  He rraises the possibiplity you have herpes zoster (singles), not HSV.  You should promply return to your doctor for possible additional testing

Also please pardon the type in answer no. 5.  It should read "overall suppression about 50%, not 90%.
Thank you for the response doctor.

I have not had any testing or swabbing done; I have considered that it could be HSV2, HSV1, or even shingles. The doctor that identified it said it was genital herpes and indeed it looked entirely like classic genital herpes with tiny clustered blisters, except for the fact that my scrotal ulcers were initially bacterially infected (he said it is possible for herpes sores to become bacterially infected due to co-infection). I am in a foreign country at the moment and cannot pay for testing here as my insurance does not cover it. I return to the US in several months and once there I will promptly get tested.

Just a few follow up questions from your response:

1) Considering I am only 25 years old, how likely is it shingles?

2) How likely is it that it could be HSV1? I had both oral sex (unprotected) and vaginal sex (protected) the night I contracted it.

3) Going back to my question about the dermatomes, can HSV jump from skin innervated by the sacral ganglia to skin innervated by the lumbar ganglia, and visa versa?

I am just a little confused about how this virus works. I was told it takes residence in the sacral ganglia, but then why is it showing up on skin that is clearly, based on all the sources I've checked, innervated by the lumbar ganglia? Am I infected in both the sacral and lumbar ganglia, or is it somehow jumping between two different dermatomes? I just want some clarification here.

I definitely plan to inform my partners and discuss condom use. These questions are really for me to understand my infection so I can properly assess my partner's risks instead of operating from a place of confusion and uncertainty.


1) The age makes little difference.  HSV is more common than shingles at age 25, but plenty of shingles cases occur in young people.  My son had it at 13.

2) HSV-2 is quite a bit more likely.  But please say more about when you think you were infected:  describe the exposure and the timing of symptoms afterward.  As noted above, I am skepical that your first outbreak was really your initial infection.

3) It is possible for more than one nerve route or ganglion to be infected initially, in which case subsequent recurrences may reflect either or both nerve roots.
I had protected vaginal sex and unprotected oral sex with a sex worker. About five days later, I noticed an ulcer on my left scrotum close to the base of the penis. The ulcer was bacterially infected, and I went to the doctor (not an infection specialist, just a GP) to get it checked out. The doctor said that it was likely a co-infection of some type of herpes along with bacteria. He did a gram stain and found a lot of gram negative bacteria and then gave me some doxycycline and Zovirax cream.

After taking the antibiotic, the bacterial infection went away, but the ulcers continued to form and spread despite use of Zovirax cream. I then noticed tiny clustered blisters that look just like the herpes in the pictures on my scrotum, forming near the ulcers. At this point, tiny blisters started to form on my inner right thigh that were very itchy. I went back to the doctor and he gave me more antibiotics and Zovirax cream. At this point, I did my own research and decided to go buy Acyclovir tablets from the local pharmacy (I am in a country where you can get drugs without any prescription). Once I started taking these, the ulcers on my scrotum started to heal and the blisters on my thigh dried up and disappeared. After about 2-3 weeks, the skin was normal.

It has been five months since and I haven't stopped taking Acyclovir and have not had any recurrences. I don't plan to stop taking Acyclovir until I get my blood test to find out what type I have.

Right now, my impression is that it is HSV2 and the sight of infection was the scrotal skin beneath the base of the penis, because this area could have come into contact with infected skin during vaginal sex. I think this makes sense because initial herpes presents bilaterally, and on the right side of my body it presented on the thigh -- both areas innervated by the same L1 nerve. I have not seen any evidence to indicate I am infected on my penis, though I understand the need to play it safe when it comes to protecting my partners. It could be that since the scrotal skin comes into contact with the penis that it spread to the sacral nerve group via auto-inoculation. But during the initial infection, which was somewhat severe, I did not see anything ever develop on my penis or buttock (sacral areas).

I am also surprised that I've had no recurrences, since I'm told the virus is at its worst during the first six months and suppression is only 70% effective at reducing outbreaks. I went through a severe bout of mononucleosis two months later (confirmed by lab test when I was back in the US for a few weeks, possibly got it from the same sex act which included kissing) and had no recurrence during that despite being so unwell. As I'm approaching six months without a recurrence, I feel like all I really have to worry about is asymptomatic shedding, though I realize recurrences can be random.

If asymptomatic shedding is my biggest worry, and herpes doesn't shed from the thicker skin of the scrotum and thigh, then maybe I can feel more peace of mind? Of course my partners will be informed and condoms will be discussed, but my case does seem somewhat atypical, no?

Thanks for the additional information.

I'm now skeptical you have herpes at all.  Presentation with an initial single ulcer in the groin or ingual fold is atypical, as are herpetic lesions on the scrotum.  That subsequent lesions "looked typical" for herpes doesn't sway me very much; lots of localized cutaneous inflammatory processes can look similar to herpes.  (Even the world's top herpes experts frequently misdiagnose it based on appearance, both missing PCR-positive lesions and calling herpes when PVR is negative.)  Also, most people with HSV-2 would have expected at least a few breakthrough outbreaks while taking acyclovir -- although maybe not with HSV-1.  It is disappointing that the original doctor apparently didn't do an HSV PCR or culture on the initial lesions.

That said, the time course of healing on oral acyclovir is consistent with herpes -- but of course most skin infections heal on their own, so the improvement could have been a coincidence.

My strong advice is that you stop taking acyclovir.  In in the next few weeks you develop any possible herpes oubreaks, see a doctor or clinic right away (within 1-2 days) for PCR testing of the lesions.  If that doesn't happen, or if such testing is inconclusive, then about 3 months after stopping the drug you should have an HSV blood test to check for antibodies to both HSV-1 and HSV-2.

Another strategy to sort this out is to contact your partner at that time.  If she is willing to be tested, you could determine whether she is infected with HSV-1 and/or HSV-2.  If negative for both, you'll be able to safely conclude you don't have herpes; and if positive, it would tell you what viral type might be anticipated if in fact you caught HSV.
Thanks doctor. That's good advice about stopping the medicine. After my final exams finish in January and I head back to the US, I will give that a try and see what happens.

Could it have been impetigo? The ulcers on my scrotum were oozing a very smelly, yellow pus and I even thought it could be chancroid which I'm told is not uncommon here in the Philippines. Anyway, I understand there's no way to truly know unless I get tested, so that's what I'm going to do when I get the chance.

Thank you.
I recommend against waiting until January.  Stop the drug now.

Impetigo is one of the skin inections that could cause such symptoms.  Chancroid is very unlikely.
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H. Hunter Handsfield, M.D.Blank
University of Washington
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