Rashes that develop during pregnancy often result in considerable anxiety or concern for patients and their families. Recognizing these pregnancy-specific dermatoses is important in identifying fetal risks as well as providing appropriate management and expert guidance for patients regarding future pregnancies. Managing cutaneous manifestations of pregnancy-related disorders is challenging and requires knowledge of potential side effects of therapy for both the mother and fetus. It also is important to appreciate the physiologic cutaneous changes of pregnancy along with their clinical significance and management.
In 2006, Ambrose-Rudolph et al1 proposed reclassification of pregnancy-specific dermatoses, which has since been widely accepted by the academic dermatology community. The 4 most prominent disorders include intrahepatic cholestasis of pregnancy (ICP); pemphigoid gestationis (PG); polymorphic eruption of pregnancy (PEP), also known as pruritic urticarial papules and plaques of pregnancy; and atopic eruption of pregnancy.2 It is important to recognize these pregnancy-specific disorders and to understand their clinical significance. The morphology of the eruption as well as the location and timing of the onset of the rash are important clues in making an accurate diagnosis.3
Clinical Presentation
Intrahepatic cholestasis of pregnancy presents with severe generalized pruritus, usually with involvement of the palms and soles, in the late second or third trimester. Pemphigoid gestationis presents with urticarial papules and/or bullae, often in the second or third trimester or postpartum. An important diagnostic clue for PG is involvement near the umbilicus. Polymorphic eruption of pregnancy presents with urticarial papules and plaques; onset occurs in the third trimester or postpartum and initially involves the striae while sparing the umbilicus, unlike in PG. Atopic eruption of pregnancy has an earlier onset than the other pregnancy-specific dermatoses, often in the first or second trimester, and presents with widespread eczematous lesions.3
Diagnosis
The pregnancy dermatoses with the greatest potential for fetal risks are ICP and PG; therefore, it is critical for health care providers to diagnose these dermatoses in a timely manner and initiate appropriate management. Intrahepatic cholestasis of pregnancy is confirmed by elevated serum bile acids (ie, >10 µmol/L), often during the third trimester. The risk of fetal morbidity is high in ICP with increased bile acids crossing the placenta causing placental anoxia and impaired cardiomyocyte function.4 Fetal risks, including preterm delivery, meconium-stained amniotic fluid, and stillbirth, correlate with the level of bile acids in the serum.5 Maternal prognosis is favorable, but there is an increased association with hepatitis C and hepatobiliary disease.6
Diagnosis of PG is confirmed by classic biopsy results and direct immunofluorescence revealing C3 with or without IgG in a linear band along the basement membrane zone. Additionally, complement indirect immunofluorescence reveals circulating IgG anti–basement membrane zone antibodies. Pemphigoid gestationis is associated with increased fetal risks of preterm labor and intrauterine growth retardation.7 Clinical findings of PG may present in the fetus upon delivery due to transmission of autoantibodies across the placenta. The symptoms usually are mild.8 An increased risk of Graves disease has been reported in mothers with PG.
In most cases, diagnosis of PEP is based on history and morphology, but if the presentation is not classic, skin biopsy must be used to differentiate it from PG as well as more common dermatologic conditions such as contact dermatitis, drug and viral eruptions, and urticaria.
Atopic eruption of pregnancy manifests as widespread eczematous excoriated papules and plaques. Lesions of prurigo nodularis are common.
Comorbidities
It is important to be aware of specific clinical associations related to pregnancy-specific dermatoses. Pemphigoid gestationis has been associated with gestational trophoblastic tumors including hydatiform mole and choriocarcinoma.4 An increased risk for Graves disease has been reported in patients with PG.9 Patients who develop ICP have a higher incidence of hepatitis C, postpartum cholecystitis, gallstones, and nonalcoholic cirrhosis.8 Polymorphic eruption of pregnancy is associated with a notably higher incidence in multiple gestation pregnancies.2