I've had a rash on the neck and back.
There are many possible causes rashes and various. We classify them according to their shape, their color, if bulky or drawings and many other features (eg If you are scaly or rather fleshy, etc..). We also consider the possible underlying health problems, rashes may occur with health problems such as allergies, dermatomyositis, lupus, and many other problems. In short, a proper assessment, a detailed history and an examination by your doctor is required to determine the cause.