What Causes Itchy Red Rashes On The Arms And Headache Despite Using Ibuprofen?

Hello. My daughter, age 7, has a low to moderate fever, complains of a headache, is fatigued. No stuffy nose of cough. Had an itchy throat yesterday, but today says her throat is fine. I also felt her glands were swollen yesterday. Today I noticed a rash on both of her arms. bigger on her right arm and small on her left. the skin is hard red and itchy, fever and headache get better with Ibuprofen but are coming back every 4-6 hours of so. this is second day she is not feeling well.