Pemphigoid gestationis is an intensely itchy rash that occurs only during pregnancy.
Pemphigoid gestationis is thought to be caused by abnormal antibodies that attack the body's own tissues—an autoimmune reaction. It is relatively rare.
The rash can begin as flat or raised red spots that often first form on the abdomen around the navel. Then blisters develop and the rash spreads. The blisters are small or large, irregularly shaped, and fluid-filled. The rash is extremely itchy.
The rash usually appears during the 2nd or 3rd trimester. However, it may appear earlier or immediately after delivery. Typically, the rash worsens soon after delivery and disappears within a few weeks or months. It often reappears during subsequent pregnancies and sometimes reappears if the woman later takes oral contraceptives. Occasionally, the baby is born with a similar rash, which usually disappears without treatment within a few weeks. Also, when women have this disorder, the risk that the fetus may die is increased.
Very rarely, the thyroid gland malfunctions in affected women.
This rash is diagnosed based on its appearance and sometimes a test for abnormal antibodies done on a tiny sample of affected skin. Tests, such as a nonstress test, ultrasonography, or electronic fetal monitoring, may be done to evaluate the fetus (see Monitoring the Fetus).
Applying a corticosteroid cream (such as triamcinolone) directly to the skin often helps. For more widespread rashes, a corticosteroid (such as prednisone) is given by mouth.