Pityriasis Rosea (PR) is a very common rash caused by a virus. It is unclear as to how this virus is transmitted, and it does not appear to be contagious. It is most common during the spring and fall.

PR usually begins with a large, scaly pink patch on the trunk called the “herald patch”. Over the course of a few weeks, smaller lesions continue to appear creating what looks like a Christmas tree on the back.

The rash of Pityriasis Rosea may mimic syphilis, a well-known and understood sexually transmitted disease. If a patient has known risk factors for contracting syphilis a blood test will be drawn to rule it out. In most cases a blood test is not needed.

Treatment is usually not necessary as the rash of PR resolves on its own over the course of a few weeks to months with no sequelae. But, topical steroids and treatment with ultraviolet light decreases any itching and hastens resolution in many cases.

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