Your description is typical, almost pahtognomonic, to urticarial reactions. They are one of the most common skin reactions and, at least with children, mostly associated with infections, particularly viral. In it self completely harmless but the itch is bad sometimes. An allergy will sometimes go with urticarial skin reaction too, but usually with other organ symptoms too. An airborne allergy, hence, will primarily create symptoms from the upper airways, like nose and eyes. A food related allergy from the mouth to the bowel.
If you have access to any antihistamines (loratadin, cetirizin etc) - try 1-2 tablets daily. It will most of the time ease the itch.
Of course go see a doc too. I only know about kids.
