Causes of Pityriasis Rosea
The exact cause of pityriasis rosea remains unknown. Most recently, pityriasis rosea has been associated most strongly with a virus from the human herpes family called human herpes virus types 6 and/or 7. Pityriasis rosea is not caused by or known to be associated with the common types of herpes virus that causes genital, oral herpes, or varicella (chickenpox). While the mode of transmission (how it gets passed between people) of pityriasis rosea is also unknown, respiratory contact has been postulated. Pityriasis rosea does not seem to be directly or immediately contagious to close contacts or health-care providers exposed to the rash. Most people with a known exposure to pityriasis rosea do not seem to contract the rash.