In patients with pityriasis rosea, what skin lesion often precedes the smaller lesions?

In patients with pityriasis rosea, the herald patch is a distinct, often oval, erythematous patch that appears first and is typically larger than the subsequent smaller lesions that follow. This herald patch usually presents on the trunk or upper arms and is an important clinical sign, as its presence can help in diagnosing pityriasis rosea.

The herald patch is characterized by its size, shape, and color, and serves as a precursor to the generalized rash that spreads throughout the body, which consists of smaller, more similar lesions. Recognizing the herald patch can aid clinicians in identifying and diagnosing this self-limiting condition early in its course.

Other lesions like fissured plaques, exudative vesicles, or scaly papules do not represent typical features in the initial stage of pityriasis rosea, and therefore, do not precede the smaller lesions in this context. The herald patch's unique role as the first sign is integral to understanding the disease's progression.