Pityriasis rosea: Causes

What causes pityriasis rosea?

Why some people get this disease is still a bit of a mystery. It’s likely caused by a virus. Dermatologists have found human herpesviruses in the rash, blood, and saliva of people who have pityriasis rosea.

How can herpesviruses cause pityriasis rosea?

These are many types of human herpesviruses. The ones found in people with pityriasis rosea are human herpesviruses 6 and 7. These types of herpesviruses cannot cause cold sores or genital herpes.

Human herpesviruses 6 and 7 are common. Many Americans become infected with them at an early age. Children often get infected when someone sneezes or kisses them. Once you get these viruses, they remain inside the body.

These viruses generally don’t cause a problem because your immune system keeps them under control. It’s possible that people get pityriasis rosea when their immune system lets down its guard, which allows the viruses to travel around the body and reproduce.

Whether this happens has yet to be proven. It’s also possible that people get pityriasis rosea when they first catch these viruses.

While the strongest evidence points to herpesviruses as the cause, more research is needed to find out what’s happening. Other causes have been suggested. These include another type of virus and bacteria.

Diagnosis can give you peace of mind

While what causes pityriasis rosea is still a bit of a mystery, we know that the rash can look like other skin conditions, including psoriasis or ringworm. A dermatologist can tell you if pityriasis rosea is causing your rash. Find out how at, Pityriasis rosea: Diagnosis and treatment.

References
Clark M, Gudjonsson JE. “Pityriasis rosea.” In: Kang S, Amagai M, et al. Fitzpatrick’s Dermatology (ninth edition). McGraw Hill Education, New York, 2019: 518-26.

Goldstein AO, Goldstein BG. (section editors: Dellavalle RP, Levy ML). “Pityriasis rosea.” UpToDate. Last reviewed: 8/2024. Last accessed: 9/2024.

Litchman G, Nair PA, et al. “Pityriasis rosea.” StatPearls. Last updated 3/1/2024. Last accessed 9/2024.

Méndez A, Stevens C, et al. “From the Cochrane Library: Interventions for pityriasis rosea.” JMIR Dermatol. 2023 Jun 5;6:e45388.

Wood GS, Reizner GT. “Other papulosquamous disorders.” In: Bolognia JL, et al. Dermatology. (fourth edition). Mosby Elsevier, China, 2018:170-2.

Written by:
Paula Ludmann, MS

Reviewed by:
Brendan Camp, MD, FAAD
William Warren Kwan, MD, FAAD
Ata Moshiri, MD, FAAD
Carla Torres-Zegarra, MD, FAAD

Last updated: 10/24/24