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Pityriasis rosea

  • Symptoms

    Attacks most often last 4 - 8 weeks. Symptoms may disappear by 3 weeks or last as long as 12 weeks.

    The rash starts with a single large patch called a herald patch. After several days, more skin rashes will appear on the chest, back, arms, and legs.

    The skin rashes:

    • Are often pink or pale red
    • Are oval in shape
    • May be scaly
    • May follow lines in the skin or appear in a "Christmas tree" pattern
    • May itch

    Signs and tests

    Your health care provider can usually diagnose pityriasis rosea by the way the rash looks.

    Rarely, the following tests are needed:

    • A blood test to be sure it is not a form of syphilis, which can cause a similar rash
    • A skin biopsy to confirm the diagnosis