odd rash and fatigue

[equfan]

About two months ago, I sprained my left ankle after moving out of Los Angeles to northern CA.  I was given an adhesive bandage to support the ankle in the first several days after the sprain.  I developed a bad rash/burn to the bandage that was limited to the area of contact.  It was BAD, like a chemical burn.  After a week or more without the bandage, the rash/burn began to subside, but then I began to develop a rash all over.  This new, widespread body rash was not like the area affected by the bandage, but I wonder if they are related.  Along with the body rash came fatigue and exhaustion.

The first doctor I went to (a GP) did not think that the body rash was poison oak, which was my own theory as I had been working around it outside and had had bouts of poison ivy years ago.  He thought that I was having an allergic reaction to Irish Spring soap, which I had begun using after I made the move to northern CA.  He prescribed prednisone and told me to get some plain, white soap.  I started the prednisone and felt immediately better.  Both rash and fatigue vanished in a day or two.  I continued on the prednisone taper feeling good.

I then traveled to MA to visit family where I grew up.  Shortly after finishing the prednisone taper, the body rash and fatigue returned.  I thought that I was reacting to the laundry detergent, so we switched to a non-allergenic detergent (the one I have used for years) and laundered all of my clothes, sheets, towels, etc.  I was also put back on prednisone and felt better.

This cycle has now repeated itself five times: rash and fatigue treated with a prednisone (methylprednisalone once) taper.  I have also been put on various antihistamines, which appear ineffective.  Blood tests have turned up nothing.  An allergist I saw a few days ago started me on hydroxyzine, which has left me almost unable to get out of bed, and which I have stopped taking.  I understand that it is often used as a sort of sedative, whereas my chief complaint is the fatigue/exhaustion, which is now much worse.

The only common denominator to my environment in northern CA and in MA I can think of is outdoor work around brush.  I have been quite careful in wearing long sleeves, jeans, boots, hats, and gloves to minimize contact with whatever plant might be affecting me.  I also notice that sweating seems to make the rash worse, which is most intense in my armpits, groin, forearms, and abdomen even though it has been elsewhere at other times, sometimes in asymmetric fashion.

I am stumped.  While the rash is annoying, I could live with it if I could be rid of the fatigue/exhaustion that accompanies it.

Help!