Recurring Linear Rash

For the past five days, I have had a recurring linear rash.  It comes on quickly and leaves just as quickly.  With the whole cycle (between when I notice it and when it is completely gone) lasting between 15-20 minutes.  I originally thought it was an allergic reaction to something I was exposed to, however, it has occured in various different places and at various times.  The first time occured while at a baseball game, I thought maybe they were weird bug bites.  Then it occured the same day at my home; we had recently gotten our home exterminated and thought it may be that.  Then we went out of town for the weekend, and it occured while I was there.  Lastly, it had never happened at work before today, and I had a really bad outbreak today.  

Please lend any help you can in this matter, it is really making me nervous.  I appreciate your help.

Thanks.

[Alan Rockoff, MD]

I obviosuly can't be sure, but I can say this:

1.  Things that come and go aren't usually very serious.  Thinsg that come and stay, or spread, are more worrisome.

2.  Linear rashes are often assoicated with external trauma, like scratching.  You may have dermaographism ("skin writing.")  This refers to welts that appear when the skin is scratched or rubbed, when histamine leaks out of mast cells in the skin and produces short-lived hives.

Here's how to check: take an unopened pen and make a design on the skin-- an X or a square.  See if that leaves a red trail of the same shape.  If it does, that's your answer.

No treatment is needed.  The body just goes through a phase like this once in a while, but it doesn't mean anything.

If you can't reproduce the marks this way and they persist, photograph them and show a doctor.

Best.

Dr. Rockoff