Rosea" most commonly refers to pityriasis rosea, a common, harmless rash that typically begins with a single larger patch (herald patch) followed by a widespread eruption of smaller, scaly spots. The rash is characterized by its pink, scaly patches (pityriasis means scale, rosea means pink) and usually clears up on its own within 6 to 12 weeks, though post-inflammatory color changes in the skin can last longer. While the exact cause is unknown, it is often linked to viral infections and is not contagious.