Pityriasis rosea is a harmless skin disease that causes scaly patches that sometimes itch over the torso, neck, arms and legs. Anyone can get it, but it is most common in people ages 10 to 35.
Typically, the disease begins with the appearance of a single large, pink, scaly, oval patch, called the "herald patch." This patch is approximately 1 inch to 2 inches long. It tends to have a salmon-colored center surrounded by a darker pink ring, which some people mistake as a sign of ringworm.
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