Health Encyclopedia

Pityriasis rosea

Definition

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

Causes, incidence, and risk factors

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 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

Itching of the lesions (mild to severe)
Skin lesion or rash
- Centers have wrinkled (cigarette paper) appearance
- Lesions appears like a scale that is attached at the edges and loose at the center
- May follow cleavage lines or appear in a "Christmas tree" pattern
- May spread
- Oval plaque, papule, or macule
- Sharp border (edge)
- Starts with a single (herald) lesion followed several days later by more lesions
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. It doesn't usually come back.

Calling your health care provider

Call for an appointment with your health care provider if you have symptoms of pityriasis rosea.

References

Habif TP. Psoriasis and other papulosquamous diseases. In: Habif TP, ed. Clinical Dermatology. 4th ed. Philadelphia, Pa: Mosby Elsevier; 2004: chap 8.

Lim HW. Eczemas, photodermatoses, papulosquamous (including fungal) diseases, and figurate erythemas. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007: chap 464.

Review Date:11/16/2008
Reviewed By:Linda Vorvick, MD, Family Physician, Seattle Site Coordinator, Lecturer, Pathophysiology, MEDEX Northwest Division of Physician Assistant Studies, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

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