A harmless rash, pityriasis rosea usually begins with a single, scaly pink patch with a raised border. Days to weeks later, salmon-colored ovals appear on the arms, legs, back, chest, and abdomen, and sometimes the neck. Patches on the back may appear "Christmas tree" shaped. The rash, whose cause is unknown, usually doesn't itch, and often goes away in 6-8 weeks without treatment.
Pityriasis rosea is characterized by the appearance of diffuse redness (erythema ) associated with a very slight scaling (fall tiny shreds of skin). 
Pityriasis rosea is a rash that occurs most commonly in people between the ages of 10 and 35, but may occur at any age. The rash can last from several weeks to several months. Usually there are no permanent marks as a result of this condition, although some darker-skinned persons may develop long-lasting flat brown spots that eventually fade. It may occur at anytime of year, but pityriasis rosea is most common in the spring and fall.

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