Pityriasis rosea

Definition
Pityriasis rosea is a skin disorder with a characteristic rash.

Causes, incidence, and risk factors
This disorder is a common skin rash of young people, especially young adults. It occurs most commonly in the fall and spring, and a virus is suspected as the cause. Although pityriasis rosea may occur in more than one person in a household at a time, it is not thought to be highly contagious.

Attacks generally last 4 - 8 weeks. Symptoms may disappear by 3 weeks or last as long as 12 weeks. There is generally a single larger patch called a herald patch followed several days later by more a rash. Although the disorder usually resolves in time, a health care provider should be consulted to rule out other disorders including syphilis.

Symptoms

     
  • Skin lesion or rash       o Starts with a single (herald) lesion       o Followed several days later by more lesions       o May follow cleavage lines or appear in a “Christmas tree” pattern       o Oval plaque, papule, or macule       o Sharp border       o May spread       o Centers have wrinkled (cigarette paper) appearance       o The lesions appears like a scale that is attached at the edges and loose at the center  
  • Itching of the lesions (mild to severe)  
  • Skin redness or inflammation

Signs and tests
Your physician can usually diagnose pityriasis rosea based on the appearance of the rash. A blood test may be required, however, to distinguish pityriasis rosea from the very similar rash seen in Secondary syphilis. Occasionally, a skin biopsy may be necessary to confirm the diagnosis.

Treatment

If symptoms are mild, no treatment may be needed.

Gentle bathing, mild lubricants or creams, or mild hydrocortisone creams may be used to soothe inflammation. Oral antihistamines may be used to reduce itching.

Moderate sun exposure or ultraviolet light treatment may help speed resolution of lesions. However, care must be taken to avoid sunburn.

Expectations (prognosis)
Pityriasis rosea usually goes away within 6 - 12 weeks. Recurrences are unusual.

Calling your health care provider
Call for an appointment with your health care provider if you have symptoms of this disorder.

Johns Hopkins patient information

Last revised: December 5, 2012
by David A. Scott, M.D.

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