What could be the rashes in my legs causing extreme itching and petechiae?

Hello doctor,

I am a 26-year-old female with no significant health history. I have anxiety, and I had hyperthyroidism in the past. I have had an itchy rash for over three months. It started as a small patch behind my left knee. It happened after having a ring shaped rash on my left thigh. I was treated for that with antifungal cream and it went away.

This new rash is completely different. I am extremely itchy to the point. It is interfering with my life. There is no obvious rash unless I have already scratched that area. I then get a bunch of small skin-colored bumps. Also, after scratching, I often get petechiae and bruising. The itch is everywhere but my face. I have been waking up wet from sweating even though my bedroom is fairly cold at night. A few times I have checked, I had a small fever of around 99.1 Fahrenheit. My doctor puts me on antihistamines (Benadryl at night, Claritin during the day) and steroid cream. It has not worked. She recently wrote me a prescription for Prednisone, but I am worried that a skin allergy just is not what I have.

I am currently taking Effexor 75 mg, Klonopin 0.5 mg when needed.