Mystery Itch

So on Wednesday evening I was cooking dinner and my back started to itch. I scratched it and then it REALLY itched. This went on for 20 minutes...I would resist scratching as long as humanly possible until I couldn't stand it any more and scratched. Eventually it went away but later my legs, then my arms, then my stomach, then my feet all would itch constantly and at random intervals. I went to bed hoping it would be gone in the morning. I scratched my feet all night long. When I got up I showered and that's when I noticed I had a fine rash all over my body. Not gross or bumpy but almost like a mild, mottled sunburn. I put some cortizone cream on my feet (they were what was itching at the time). That did little to help. I called the Nurse Hotline and they reccomended a baking soda bath and an antihistimene and to watch for more serious symptoms. I did ok for the day and by evening the rash was better but I still itched. I took an antihistimene before bed and I feel a little better this morning. There are still some really itchy spots (like the bottom's of my feet - weird) and the rash is mostly gone. I have no clue what could have caused this as I don't have any known allergies and I don't think I ate anything new that day. Didn't garden or get into anything unfamiliar. No new medication. I am sure it had to be an allergic reaction of some kind but to what I have no clue and I wish I did because I would like to avoid this feeling again at all costs. Whatever it was was not contagious as neither of the children or Brian has had the issue and we have hugged and snuggled eachother so I am sure I reacted to something but I don't know what.
Anyway, all is well, just had to share my little mystery.