Symptoms:

Attacks most often last 4 - 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

Signs and tests:

Your health care provider can usually diagnose pityriasis rosea by the way the rash looks.

Rarely, 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