From my experience, practically all itchy spots disappear after using clay. The main reason why itchy spots occur is because toxins are being removed through the skin at that spot hence the itch. by putting clay there, it pulls out these toxins at a faster rate and so the itch disappears because the toxins are now drawn inside the clay and out of your body.
it is also possible for new itch spots to occur because your body has sensed that it has removed internal toxins successfully and so will program for another group of toxins to come out in a different part of the body. these are not allergic reactions because there are no rashes left after you remove the clay after the itch has disappeared. the skin appears normal as usual without the itch.