From the symptoms and pictures,it looks like nummular eczema(stubborn, itchy rash that forms coin-shaped patches on the skin.Found mainly in
adults but can oocur in children
also) , hives(red, itchy, raised areas of skin
that appear in varying shapes and sizes. They have a tendency to change size rapidly and to move around, disappearing in one place and reappearing in other places, often in a matter of hours.Many cases of hives are "idiopathic," meaning no cause is known.