PUPP

Polymorphous eruption of pregnancy is a skin condition which affects the abdominal skin in pregnant women. The condition initially consists of small elevated spots around the umbilicus, which are pink in color and often surrounded by a ring of paler skin. Lesions will coalesce into larger red plaques, and may involve the thighs, buttocks and even limbs as the condition progresses. Lesions are accompanied by intense itching.

Polymorphous eruption of pregnancy affects only women, and only during pregnancy. The condition typically appears in the last trimester, and resolves after delivery. The exact cause is unknown, but the condition is thought to develop due to the stretching of skin in the affected area, presenting as an allergy to the stretching process. It is more common and severe during first pregnancies, and is accompanied by increased weight gain, heavier than average infants, and increased risk of giving birth to twins. Additionally, polymorphous eruption of pregnancy may be passed to infants, but typically resolves within the first few days of life.

Differential Diagnosis (Other conditions with similar appearance)
Contact Dermatitis
Scabies
Seabather’s Eruption
Drug eruptions
Urticaria
Erythema multiforme
Insect Bites

Polymorphous eruption of pregnancy is typically diagnosed based on the characteristic appearance of the affected area. Skin biopsy and serum level tests may be performed to confirm the diagnosis and rule out similar appearing conditions.