Pemphigoid Gestationis

Updated: Jun 02, 2017
  • Author: Victor A Teran; Chief Editor: William D James, MD  more...
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Overview

Background

Pemphigoid gestationis (PG) is a rare autoimmune bullous dermatosis of pregnancy (see the image below). The disease was originally named herpes gestationis for the herpetiform morphology of the blisters, but this term is a misnomer because pemphigoid gestationis is not related to or associated with any active or prior herpes virus infection.

Tense bullae are present on the arms of this other Tense bullae are present on the arms of this otherwise healthy 32-year-old primigravida woman.

See Diagnosing Dermatoses in Pregnant Patients: 8 Cases to Test Your Skills, a Critical Images slideshow, for help identifying several types of cutaneous eruptions associated with pregnancy.

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Pathophysiology

Pemphigoid gestationis is a pregnancy-associated autoimmune disease. Most patients develop antibodies against the hemidesmosomal protein BP180 (BPAG2, collagen XVII), and, in some cases, antibodies also form against another hemidesmosomal protein, BP230. [1] However, whereas the role of anti-BP180 is well defined in the pathogenesis of pemphigoid gestationis, [2] BP230 is intracellular and the clinical significance of anti-BP230 is uncertain. [3] Historically known as herpes gestationis factor, these circulating antibodies belong to the heat-stable immunoglobulin G1 subclass. The binding of immunoglobulin G to the basement membrane at the dermoepidermal junction triggers an immune response by neutrophils and eosinophils, leading to the formation of subepidermal vesicles and blisters. In 1999, Chimanovitch et al [4] demonstrated that pemphigoid gestationis sera recognize five distinct epitopes within BP180 NC16A, four of which have been reported as major antigenic sites targeted by bullous pemphigoid antibodies.

The trigger for the development of autoantibodies in persons with pemphigoid gestationis remains elusive. Cross-reactivity between placental tissue and skin has been proposed to play a role. Pemphigoid gestationis has a strong association with HLA-DR3 (61%) and HLA-DR4 (52%), or both (43%), [5] and virtually all patients with a history of pemphigoid gestationis have demonstrable anti-HLA antibodies. The placenta is known to be the main source of disparate (paternal) antigens and can thus present an immunologic target during gestation. One possible mechanism for autoantibody generation is that aberrantly expressed fetal major histocompatibility complex (MHC)–II on trophoblasts and amniochorionic stromal cells permits maternal detection of paternal MHC-II. [6] BP180 is expressed on both amniotic epithelial cells of the placenta and keratinocytes at the dermoepidermal junction. [7] Thus, BP180 may be presented to maternal MHC-II in the presence of paternal MHC-II and recognized as a foreign antigen, leading to the formation of antibodies that are cross-reactive toward BP180 in the epidermis.

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Epidemiology

Frequency

United States

In the United States, pemphigoid gestationis has an estimated prevalence of 1 case in 50,000 pregnancies. [3]

International

Findings from European studies suggest that pemphigoid gestationis has an overall incidence of 0.5 cases per million people per year. In 1999, Jenkins et al [8] described the largest cohort of 87 patients in the United Kingdom with a total of 278 pregnancies, of which 142 were complicated by pemphigoid gestationis.

Race

Pemphigoid gestationis is less common among blacks than whites, which might reflect its association with specific HLA haplotypes.

Sex

This condition only affects females.

Age

Pemphigoid gestationis occurs in women of childbearing age.

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Prognosis

Pemphigoid gestationis typically regresses without scarring within weeks to months after delivery. Pemphigoid gestationis may recur in subsequent pregnancies and may be precipitated by menses and the use of oral contraceptives.

Mortality/morbidity

No increase in fetal or maternal mortality has been demonstrated. A greater prevalence of premature and small-for-gestational-age (SGA) babies is associated with pemphigoid gestationis. Of infants, 5-10% born to affected mothers may present with transient cutaneous involvement that resolves as maternal autoantibodies are cleared.

Patients with pemphigoid gestationis have a higher relative prevalence of other autoimmune diseases, including Hashimoto thyroiditis, Graves disease, and pernicious anemia, which are also associated with HLA-DR3 and DR-4 haplotypes

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Patient Education

Mothers with pemphigoid gestationis should be counseled regarding potential sequelae for their infant, such as SGA, prematurity, and transient blistering. Patients also should be aware that pemphigoid gestationis may recur with subsequent pregnancies, resumption of menses, and use of oral contraceptive agents.

The goals of therapy (ie, control pruritus, suppress extensive blistering but not totally eliminate blister formation) should be discussed with the patient prior to treatment. Patients should understand the benefits and potential adverse effects of all prescribed medications.

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