My four year old daughter is having persistent welts that come and go frequently throughout the day. For the past week they have been almost constant. They appear suddenly and last for 15-30 minutes. they itch a little. They are on her arms, torso, neck and face. They seem to happen when her skin is scratched or tickled. I have taken her to an allergist . He said it is a problem where the histamines cause swelling at the site of contact that is irritating (such as after a tickling ). Should I take her back to the allergist? He said it is not a problem and she will hopefully grow out of it. Could it be a reaction to stress? heat? pollens? Is ithere an underlying problem I should be searching out?