The cause is unknown.pityriasis rosea is caused by a viral or bacterial infection.It also is not due to any type of allergy. Pityriasis rosea is not a sign of any internal disease.

A virus may cause this rash. Like other known viral diseases, pityriasis rosea usually occurs only oncein an individual, and occasionally makes a person feel slightly ill. But the virus theory has not been proven. Unlike many viruses, however, pityriasis rosea does not seem to spread from person to person.

Symptoms of pityriasis rosea

starts with a single lesion
sharp border
itching of the lesion
May spread
Centers have wrinkled appearance
oval papule,macule

Treatment of pityriasis rosea

Treatment is generally directed at alleviating pruritus and consists of oral antihistamines, midpotency topical glucocorticoids, and, in some cases, the use of UV-B phototherapy.

for itching medicated lotions and creams may be enoughto provied relife.
patients whose lesions have a red appearance under thin white scales, or whose pruritus is made worse by warmth or exercise.