Skin disorders of pregnancy.

Skin disorders of pregnancy fall into three major groups: disorders due to physiologic changes, specific skin disorders of pregnancy, and skin tumors. Elevated levels of estrogen and progesterone stimulate melanogenesis, which causes hyperpigmentation, including melasma; high levels of circulating hormones also cause vascular changes and alter hair growth cycles. Specific skin disorders of pregnancy range from pruritic urticarial papules and plaques of pregnancy and pruritus gravidarum, which are fairly common, to pemphigus gestationis and impetigo herpetiformis, which are rare. Common skin tumors in pregnant women include pyogenic granuloma, which occurs primarily in the gingiva, and molluscum fibrosum gravidarum, or skin tags. While the effect of pregnancy on malignant melanoma continues to be disputed, recent studies indicate that long-term survival is close to that in the general population, although the disease-free interval is reduced.