Hi, I Am 26 Weeks Pregnant And For The Past

Hi, i am 26 weeks pregnant and for the past 2 weeks i have had horrible itching on my upper to mid legs. They will randomly itch and I'll scratch then a bruise will form. It'll feel like little white or red bumps to the area. I called my obgyn and she said to get some cream and to call back If it for worse. I have been taking benadryl but it isn't helping. They get so itchy that my legs get so red. I wash my sheets constantly andi have unscented soap in the shower. I just don't know what it could be? I checked my house for mold bc i thought it could be mold spores. I am very clean person and just don't get why it's only on my legs! I mainly notice at night but they do itch during the day too.