Special Feature

Dermatologic Disorders of Pregnancy

By Steven G. Gabbe, MD

During the course of prenatal care, patients frequently present with concerns about dermatologic changes related to pregnancy or with dermatoses specific for pregnancy. To assist the obstetrician in caring for these patients, this review will describe the skin changes associated with normal pregnancy, identify specific dermatoses of pregnancy, describe dermatoses that may be exacerbated by pregnancy, and develop a plan for the evaluation and treatment of pregnant patients presenting with a dermatologic disorder in pregnancy.

Normal pregnancy is characterized by a variety of skin changes, including hyper pigmentation, hirsutism, striae distensae, and vascular changes.1 Hyper pigmentation is common and is associated with an increase in melanocyte-stimulating hormone. Darkening may occur in the areolae of the breast, the linea alba, and pigmented nevi. These changes usually regress postpartum. Hyperpigmentation of the face, melasma or chloasma, is observed in most pregnant women and is increased with exposure to sunlight. It may lighten after delivery but will persist in some form in 30% of women. Melasma may also occur with oral contraceptive use. During pregnancy, there is a slower conversion of hair growth from the growth phase (or anagen) to the resting phase (or telogen). For this reason, increased hair on the face, limbs, and back may be seen. These changes usually regress within six months after delivery. Striae distensae, pink or purple atrophic longitudinal bands occur on the abdomen of most pregnant women. These changes may be associated with stretching as well as the increased levels of cortisol and estrogen, and they usually fade postpartum. Vascular changes due to the increasing estrogen levels observed during gestation are common, including spider angiomata, palmar erythema, and capillary hemangiomas. These usually regress after delivery.

In a detailed study of 200 women referred to a special clinic for dermatoses of pregnancy, Vaughan Jones and associates found that the most common reason for referral was eczema.2 The two dermatoses of pregnancy that most often led to referral were polymorphic eruption of pregnancy (PEP), formerly known as pruritic urticarial papules and plaques of pregnancy (PUPPP) and pemphigoid or herpes gestationis.

Eczema is commonly associated with a personal or family history of atopy including asthma or hay fever. Its distribution is variable, usually on the limbs and/or trunk and face. Eczema may occur in an acute, subacute, or chronic form, with the subacute presentation common, appearing as red, scaling, and numular lesions. Eczema can be treated successfully with topical corticosteroids, emollients, or ultraviolet light phototherapy.

Polymorphic eruption of pregnancy is the most common dermatosis of pregnancy, observed in 1/160-1/300 women.1-3 It occurs in nulliparous women in the third trimester or postpartum period. Recurrence in subsequent pregnancies is rare, and PEP is not associated with adverse fetal outcomes. The onset is often in abdominal striae with subsequent spread over 2-3 days to the breasts, upper thighs, and arms. The periumbilical area and face are spared. PEP is characterized by a variety of lesions including 1-2 mm erythematous papules surrounded by a narrow, pale halo that later coalesce into urticarial plaques. Small vesicles may also develop. Occasionally, a skin biopsy may be required to rule out pemphigoid gestationis, but in most cases, PEP can be diagnosed by its appearance and characteristic presentation. PEP is more commonly seen with a male fetus, and recent studies have identified fetal DNA in the maternal dermis or epidermis of women with PEP.4 The treatment for PEP includes antihistamines such as chlopheniramine, diphenhydramine, hydroxyzine, or promethazine. Topical steroids such as fluocinonide 0.05% ointment or triamcinolone 0.1% ointment may be used. Systemic corticosteroids may be required in the most severe cases. Induction of labor may also be considered as symptoms usually regress postpartum.

Pemphigoid gestationis is a rare autoimmune bullous disorder closely related to bullous pemphigoid.1-3 It occurs in approximately 1/7000 pregnancies with its onset usually in the second or third trimester or postpartum. Recurrence is common, and the disorder may appear earlier in subsequent pregnancies and be more severe. It is associated with other autoimmune diseases such as Graves’ disease. Pemphigoid gestationis presents as pruritic erythematous plaques that develop into vesicles or bullae. The abdomen is involved initially, including the periumbilical region, with subsequent spread to the extremities. Skin biopsies reveal characteristic IgG and Complement 3 staining along the basement membrane between the epidermis and dermis. Pemphigoid gestationis is associated with uteroplacental insufficiency and intrauterine growth restriction. For this reason, antepartum fetal testing has been recommended. Neonatal involvement has been observed in up to 10% of cases due to transplacental antibody passage. Neonates developed generalized erythematous plaques with vesicles that resolve spontaneously in days to weeks. Treatment of pemphigoid gestationis includes topical steroids and antihistamines in mild cases, although most patients will require systemic corticosteroids, prednisone 40-60 mg per day. Of note, oral contraceptives may produce flares in pemphigoid gestationis.

Intrahepatic cholestasis of pregnancy is a common cause of pruritis during gestation.1 It usually appears in the third trimester and is marked by nocturnal pruritis that is progressive but resolves soon after delivery. There are no characteristic skin abnormalities. The diagnosis of intrahepatic cholestasis of pregnancy is based on a three-fold increase in fasting serum bile acids. It is the deposition of bile acids in the skin that is responsible for the pruritis. Bilirubin levels may be increased, but usually not above 5 mg/dL, and serum transaminase levels are normal or moderately elevated. Intrahepatic cholestasis of pregnancy has been associated with an increase in preterm birth and fetal death. For this reason, antepartum fetal surveillance and elective delivery have been advised. If prolonged for several weeks, intrahepatic cholestasis of pregnancy may result in impaired reabsorption of vitamin K, decreased prothrombin production, and a prolonged prothrombin time. Treatment includes antihistamines and, in most cases, ion-exchange resins such as cholestyramine. These agents may take several weeks to become effective.

As noted above, nevi may increase in size, and new nevi may develop during pregnancy. A skin biopsy should be considered if melanoma is suspected.1 Lesions marked by darkening, irregular borders, satellite pigmentation, elevation, ulceration, and bleeding are characteristic of a melanoma. The effect of pregnancy on the prognosis for melanoma has been controversial. Pregnancy does not appear to affect the five-year survival of stage I melanoma. Patients who have been treated for melanoma should wait 2-3 years before attempting another pregnancy.

In evaluating a patient with a dermatosis of pregnancy, a careful history is important.2,3 One should determine if a skin disorder was present in a prior pregnancy. Has there been an exposure to allergens, including drug or occupational exposures? Does the patient have a past or current history of atopy? How long has the rash been present, when did it begin, and what are its distribution and characteristics? Are there associated symptoms? Urticaria, papules, and vesicles on the trunk suggest PEP. Vesicles and bullae on the trunk are consistent with pemphigoid gestationis. Unlike PEP, pemphigoid gestationis involves the periumbilical area. Skin biopsy should be considered to confirm the diagnosis of pemphigoid gestationis. Treatment for most patients will include antihistamines and topical corticosteriods, although systemic cortiocosteriods may be required for pemphigoid gestationis. Antepartum fetal surveillance should be used in cases of pemphigoid gestationis and intrahepatic cholestasis of pregnancy. Elective delivery may be advised to relieve symptoms in cases of PEP or intrahepatic cholestasis of pregnancy. In patients with normal physiologic skin changes of pregnancy, the basis for these changes should be explained and the patient reassured.

References

1. Gordon MC, Landon MB. Dermatologic Disorders. In: Gabbe SG, Niebyl JR, Simpson JL, eds. Obstetrics: Normal & Problem Pregnancies. 3rd ed. London, England: Churchill Livingstone; 1996:1183-1192.

2. Vaughan Jones SA, et al. Br J Dermatol 1999;141: 71-81.

3. Vaughan Jones SA, et al. J Am Acad Dermatol 1999;40:233-241.

4. Aractingi S, et al. Lancet 1998;352:1898-1901.