Pityriasis rosea and pityriasis versicolor are completely different conditions. Pityriasis rosea is a disease caused by a herpes virus infection, which is contagious. On the other hand, pityriasis versicolor is an inflammatory skin disease, which is not contagious. The cause is not particularly clear, but it may be related to infections or allergies. Furthermore, the treatments for pityriasis rosea and pityriasis versicolor are different. Pityriasis rosea can be treated with antiviral medications, along with symptomatic treatments such as reducing fever, etc. Pityriasis versicolor is recommended to be treated with antiallergic or astringent medications.