Brown spots on the back that come and go

Hi,

Welcome to the ehealthforum. I am glad to help you out. One of the possibilities that can present with such rash which disappears is of pityriasis versicolor. It is a common skin infection caused by the yeast Malassezia furfur. This skin disease commonly affects adolescents and young adults, especially in warm and humid climates. It may present with pale rash which clears up with treatment and the skin eventually tans normally with sun exposure. The other possibilitie are of hives and pityriasis rosea.

I sincerely suggest you to consult a dermatologist and get it evaluated. It is very difficult to precisely confirm a diagnosis without examination and investigations, and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care.