Pityriasis Rosea may begin with a "herald" patch, a one to three inch pink patch that may go unnoticed. A few days later the herald patch is followed by a pink rash found commonly on the trunk of the body, and occasionally on the arms and thighs.
Treatment is necessary only if itching becomes bothersome. 25 mg Benadryl can be used for daytime itching. If the Benadryl causes drowsiness, you may try Zyrtec or Allegra. You may use 50 mg or 100 mg of Benadryl for nighttime itching.
If the symptoms have not cleared up within six weeks, make an appointment to see your health care provider.