Suggest Remedy For Small Itchy Bumps At Night Time

for three years I have gotten welts on my body that never occur in the same place and vary in size from small bumps to bigger than a quarter. I get them most nights (they do itch at times) and my daughter calls it bedtime disease . It started during my second deployment to Iraq and I had hair loss on my legs. I went to see the dermatologist and they did scrapes to look for anything and found nothing. I can feel them when I start to get them...any ideas?