Pityriasis rosea facts
- Pityriasis rosea begins as a single, large pink patch found on the trunk called the "herald patch."
- The herald patch is followed one to two weeks later with smaller pink patches in a "Christmas tree" configuration.
- Pityriasis rosea is generally asymptomatic except for the appearance.
- Pityriasis rosea is mildly itchy in 50% of cases and clears spontaneously in an average of six to eight weeks.
- Pityriasis rosea is sometimes accompanied by mild, flu-like symptoms and may mimic fungal infection and other conditions.
- Pityriasis rosea has no long-lasting health effects and is not directly contagious.
- Lifelong immunity often occurs after one episode of pityriasis rosea.
What is pityriasis rosea?
Pityriasis rosea is a common rash usually seen in individuals between 10-35 years of age. The rash typically lasts six to eight weeks, rarely extending 12 weeks or longer. Once a person has pityriasis rosea, it generally does not recur in their lifetime.
Pityriasis rosea characteristically begins as an asymptomatic single, large pink, scaly patch called the "herald patch" or mother patch, measuring 2-10 centimeters. The herald patch is a dry pink to red patch which appears on the back, chest, or neck and has a well-defined, scaly border.
One to two weeks following the initial appearance of the herald patch, a person will then develop many smaller pink patches across their trunk, arms, and legs. The second stage of pityriasis rosea erupts with a large number of oval spots, ranging in diameter from 0.5 centimeter (size of a pencil eraser) to 1.5 centimeters (size of a peanut). The individual spots form a symmetrical "Christmas tree" pattern on the back with the long axis of the ovals oriented in the "Lines of Blaschko" (invisible skin lines of embryonic origin). This rash is usually limited to the trunk, arms, and legs, rarely occurring on the face and neck. Pityriasis rosea usually spares the face, hands, and feet.