Pityriasis rosea is a common type of skin rash seen in young adults.
Rash - pityriasis rosea; Papulosquamous - pityriasis rosea; Herald patch
Pityriasis rosea is believed to be caused by a virus. It occurs most often in the fall and spring.
Although pityriasis rosea may occur in more than one person in a household at a time, it is not thought to spread from one person to another. Females seem to be more affected than males.
Attacks most often last 4 to 8 weeks. Symptoms may disappear by 3 weeks or last as long as 12 weeks.
The rash starts with a single large patch called a herald patch. After several days, more skin rashes will appear on the chest, back, arms, and legs.
The skin rashes:
- Are often pink or pale red
- Are oval in shape
- May be scaly
- May follow lines in the skin or appear in a "Christmas tree" pattern
- May itch
Other symptoms may include:
- Sore throat
- Mild fever
Exams and Tests
Your health care provider can often diagnose pityriasis rosea by the way the rash looks.
In rare cases, the following tests are needed:
- A blood test to be sure it is not a form of syphilis, which can cause a similar rash
- A skin biopsy to confirm the diagnosis
If symptoms are mild, you may not need treatment.
Your provider may suggest gentle bathing, mild lubricants or creams, or mild hydrocortisone creams to soothe your skin.
Antihistamines taken by mouth may be used to reduce itching. You can buy antihistamines at the store without a prescription.
Moderate sun exposure or ultraviolet (UV) light treatment may help make the rash go away more quickly. However, you must be careful to avoid sunburn.
Pityriasis rosea often goes away within 4 to 8 weeks. It usually doesn't come back.
When to Contact a Medical Professional
Call for an appointment with your provider if you have symptoms of pityriasis rosea.
Dinulos JGH. Psoriasis and other papulosquamous diseases. In: Dinulos JGH, ed. Habif's Clinical Dermatology: A Color Guide in Diagnosis and Therapy. 7th ed. Philadelphia, PA: Elsevier; 2021:chap 8.
James WD, Elston DM, Treat JR, Rosenbach MA, Neuhaus IM. Pityriasis rosea, pityriasis rubra pilaris, and other papulosquamous and hyperkeratotic diseases. In: James WD, Elston DM, Treat JR, Rosenbach, MA, Neuhaus IM, eds. Andrews' Diseases of the Skin: Clinical Dermatology. 13th ed. Philadelphia, PA: Elsevier; 2020:chap 11.