Recurring rash - eczema or herpes??

On occasion I get a very itchy rash on my left butt cheek (pretty much on my panty line).  I've never really paid much attention to it b/c I just assumed it was herpes b/c it lasts a week and then goes away.  However, when it first happened I was not seeing anyone and was not sexually active.  I do get cold sores on my mouth and they hurt.  The rash on my butt dosen't hurt - it just drives me crazy w/ all the itching.  I don't seem to get the rash & cold sore at the same time.  From what I recall (it's been a year sense the last rash) there is a yellowish coating on top of the redness - it seems scally - I don't know if there are blisters b/c I havent looked that closely.  I'm not sure if it got larger b/c I scratched it so much but the last time I had it it was about 3 inches long - seemed to get worse the more I scratched.  The first time it appeared I thought it was a spider bite - it went away and then a week later came back.  There was a time or two when the area was a little swolen and no rash appeared - I only new about the soreness b/c I was doing crunches and felt it.

Herpes isn't the only skin condition that recurres in the same spot and I'm sure hoping I was wrong.  Could this be some type of eczema or does it sound like herpes?

I'm going to get it checked out as soon as it happens again.

I would appreciate your insite.

Thanks!

[Alan Rockoff, MD]

The location and the fact that your rash does reoccur in the same place does suggest herpes, but someone would have to see it up close (and freshly-appeared) to be sure.  A herpes 2 blood test might also help, because herpes of the buttocks is genital herpes.  If that's what it is, you need to assume that you can shed virus even when you're not having an outbreak, and can spread the virus to a partner who doesn't have it.  Of course, you'll want to be sure that's what you have before drawing any conclusions.

Best.

Dr. Rockoff