Full body rash mostly on my back that is itchy, flaky & dry looking. It started about a wk ago & I did change soap about 3 weeks ago. Is this the cause?

Doctor can examine. Rashes are hard to describe in words. Usually, a doctor has to look at a rash to decide on a cause. For common rashes such as eczema, mild reactions to plants or chemicals (the soap?), excessive dryness, or little itchy bumps, the doctor may recommend over-the-counter cortisone cream two or three times a day for 1 week. For fungal infections like t. Versicolor, selenium shampoo may be recommended.