Fetal DNA in skin of polymorphic eruptions of pregnancy.

Background: Polymorphic eruptions of pregnancy (PEP) are common cutaneous disorders of unknown origin that occur usually after week 34 of gestation. Since pregnancy is associated with peripheral-blood chimerism, particularly during the third trimester, we studied the role of fetal cells in the development of the skin lesions.

Methods: We studied samples of skin from ten women with PEP who were carrying male fetuses and 26 women with normal skin or non-PEP skin disorders (13 carrying male and 13 carrying female fetuses). Epidermis and dermis were dissected from the samples, and the DNA was extracted. PCR with primers specific for the SRY gene was used to detect male DNA.

Findings: Male DNA was detected in dermis or epidermis from skin lesions of six of the ten women with PEP. No male DNA was detected in any of the 26 women without PEP.

Interpretation: Fetal cells can migrate to skin during gestation, where they seem to be associated with the development of cutaneous disorders of pregnancy.