Herpes gestationis or pemphigoid gestationis (PG) is a bullous (characterized by blistering, such as a second-degree burn) disease developing in association with pregnancy. It is believed to be an autoimmune disorder. It occurs during pregnancy, typically in the second or third trimester, and/or immediately following pregnancy. It was originally called herpes gestationis because of the blistering appearance, although it is not associated with the herpes virus. Diagnosis of PG becomes clear when skin lesions progress to tense blisters during the second or third trimester. PG typically starts as a blistering rash in the navel area and then spreads over the entire body. It is sometimes accompanied by raised, hot, painful welts called plaques. After one to two weeks, large, tense blisters typically develop on the red plaques, containing clear or blood-stained fluid. PG creates a histamine (compound involved in local immune responses) response that causes extreme relentless itching (pruritus). PG is characterized by flaring and remission during the gestational and sometimes post partum period. Usually after delivery, lesions will heal within months, but may reoccur during menstruation.