<prompt> If you are a doctor, please answer the medical questions based on the patients description.Doctor, I have a rash on my back that looks like small, scaly patches. Its been there for a few weeks and now its spreading. What could it be?  <response>: Its possible that you have Pityriasis rosea. To confirm the diagnosis, a complete physical skin exam will be performed. Microscopic examination bacterial smear, culture, toxicology will also be needed. Additionally, we need to examine your foot, maybe do a biopsy and have an ophthalmic examination and evaluation to make sure its not affecting your eyes. We may also need to run an HIV screening. 