It has been postulated that IgM antibodies to keratinocytes cause the secondary form of the eruption. Certain drugs that cause a pityriasis rosea-like eruption have been implicated in the etiology of this disorder. The clinical course and distribution of lesions are highly characteristic. Because lesions of pityriasis rosea may closely resemble those of secondary syphilis, a serologic test for syphilis may be indicated. Pityriasis rosea lesions resolve spontaneously after 6 to 8 weeks.
Lesions are variably pruritic.
Symptoms should be treated with bland emollients or systemic antipruritics. Sun exposure may accelerate clearing. A recent study found that 10 erythemogenic exposures of UVB substantially decreased the extent of pityriasis rosea, although it neither altered the duration of the disorder nor improved the itching.