Pityriasis rosea.

Pityriasis rosea is a common, self-limited, scaling disorder of unknown etiology, seen predominantly in young adults. The lesions, typically found on the trunk and proximal extremities, are ovoid, salmon-colored and symmetric. A "herald patch" appears in 70 percent of cases. Variants appear frequently. Papular, urticarial, vesicular or hemorrhagic lesions may be seen. Management with antipruritic lotions, emollients or antihistamines may be necessary to relieve itching.