It is heralded by one large patch somewhere on the upper trunk that is then followed by the appearance of other smaller patches gradually spreading down over the rest of the trunk, upper arms, and legs. The rash is not itchy or bothersome in a physical way. The individual is not sick in any way. It is just there as something visible to patient and family. Pityriasis comes to the doctor's attention only because it is there and in need of diagnosis.
Treatment is minimal to none.
The cause of pityriasis is not clearly known. The rash comes on over a period of about ten days, stays without change for another week or two, and then gradually begins to fade. It takes about six weeks for all signs of the rash to disappear. It is not contagious in any way and is not likely to ever appear again. The only treatment that is sometimes necessary is the application of a cream that helps overcome dryness, irritation, and discomfort.