What causes pityriasis rosea (PR)?

Pityriasis rosea is a common, harmless skin condition. The cause is unknown.

1. Pityriasis rosea is not contagious.

2. Pityriasis rosea clears up in about 6-12 weeks, sometimes a little longer. When clear, the skin returns to its normal appearance. Typically, there will not be scars.

3. Pityriasis rosea is not related to bacteria, fungus, foods, medicines or nervous upsets.

4. Pityriasis rosea disappears by itself.

5. A single scaling spot (“the herald patch”) often appears 1 to 20 days before the general rash. The rash covers mainly the trunk but may spread to the thighs, upper arms and neck.    Pityriasis rosea usually avoids the face, although sometimes a few spots spread to the cheeks.

6. Second attacks of pityriais rosea are rare.

7. Some dermatologists have suggested that a virus may cause this rash. This is based on the fact that the rash usually only occurs once and can occasionally make people feel ill.

8. There are different variants of PR.