​Dermatology - Pityriasis Rosea

​Dermatology - Pityriasis Rosea

Acute exanthematous eruptions with a peculiar self-limited history and unique form are known as Pityriasis Rosea (PR). usually manifests between the ages of 10 and 43, while it can sporadically affect younger and older people. PR typically manifests in the spring and fall, and strong evidence links it to the reactivation of closely related β-herpes viruses, HHV-7 or HHV-6.


In 80% of instances, a single or many herald patches appear before the generalized exanthema. This is a salmon-red, round, slightly elevated plaque or patch that measures 2-4 cm and has fine collarette scale around the edges. Following the lines of cleavage in a "Christmas tree" pattern, one to two weeks later, there are pink or tawny thin scaling papules and patches with marginal collarette. Lesions rarely occur on the face and neck and are often limited to the trunk and proximal parts of the arms and legs.

The differential diagnosis consists of drug eruptions (captopril, barbiturates, etc.), guttate psoriasis (no marginal collarette), small plaque parapsoriasis, erythema migrans with secondary lesions, erythema multiforme, and tinea corporis. The clinical diagnosis is made.


To relieve pruritus, apply topical antipruritic creams or take oral antihistamines. Apply topical glucocorticoids to lesions. Treatment started during the first week after eruption may be beneficial, as may exposure to natural sunlight or UVB phototherapy. A brief course of systemic glucocorticoids may be necessary in severe situations.