What type of rash does pityriasis rosea begin with?

Pityriasis rosea typically begins with a solitary salmon-colored macule, often referred to as the "herald patch." This initial lesion is usually larger than the subsequent smaller lesions that develop on the body. The herald patch appears suddenly and is generally oval-shaped, sometimes accompanied by mild flaking. It serves as a prominent characteristic of pityriasis rosea and may be misidentified as other dermatologic conditions initially.

The progression of this rash usually includes the appearance of smaller lesions that follow a "Christmas tree" pattern on the trunk and limbs, but recognizing the herald patch as the initial presentation is crucial for diagnosis. Understanding this typical early manifestation aids in distinguishing pityriasis rosea from other skin conditions, which may present differently, such as with multiple lesions from the outset or in different colors and shapes.