Skin allergies?

So I've been getting really weird patches all over my body. They itch tremendously. They come up as little purple / red dots that will continue to stay for a few days even after they stop itching. Or I get these bigger patches that also itch me that are just a bit red. Their smooth to the touch, but are very hot on the skin. I'm prone to skin problems such as chronic hives & eczema, but I've never had this skin issue before with either. I've noticed the big red patches do go away fairly quickly after I stop itching it. I recently within the past week switched my medications from Visteril to Prozac. I spoke with my therapist about being so itchy all over & she said the Visteril was probably treating skin allergies I didn't know I had (since I was on it for 3-4 years). I'm not sure what is going on with my skin, I haven't done anything different or used anything that I'm not already suppose to use. I think it might be where I stopped the Visteril, but I started this about 2-3 weeks after I quit taking them & before I started the Prozac so I know my medication now isn't the cause. I guess it's still possible. Has anyone had this issue? What have you done to help it & what was it?