Definition

Pityriasis rosea is a common type of skin rash seen in young adults.

Causes, incidence, and risk factors

Pityriasis rosea occurs most commonly in the fall and spring. It is believed to be caused by a virus. 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 large patch (herald patch) followed several days later by a rash.

Symptoms

• Skin lesion or rash
  • Starts with a single (herald) lesion
  • Followed several days later by more lesions
  • May follow cleavage lines or appear in a "Christmas tree" pattern
  • Oval plaque, papule, or macule
  • Sharp border
  • May spread
  • Centers have wrinkled (cigarette paper) appearance
  • 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 health care provider can usually diagnose pityriasis rosea by the way the rash looks. A blood test may be needed to rule out a form of syphilis, which can cause a similar rash. Occasionally, a skin biopsy may be needed 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. Antihistamines, taken by mouth, may be used to reduce itching.

Moderate sun exposure or ultraviolet light treatment may help make the lesions go away more quickly. 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.