Urticarial plaques with a preference for the abdomen and periumbilical area.

PEMPHIGOID GESTATIONIS

Pemphigoid gestationis (PG), previously known as herpes gestationis, is an autoimmune blistering disorder most commonly associated with pregnancy although it may occur in association with trophoblastic tumors, hydatidiform mole or choriocarcinoma. PG binds the NC16A domain of collagen XVII (BPAG2, BP180).

• In a series of 87 patients, the average age was 28 years and the onset ranged from 5 weeks gestation to 35 days postpartum. 18% presented in the first trimester, 34% in the second, 34% in the third and 14% presented postpartum. In that same review, there was no association with change in male partner as previously suggested.
• Most patients flare with delivery.
• Autoimmune blistering disease of pregnancy
• Periumbilical urticarial plaques typical
• PG is associated with adverse pregnancy outcome (e.g. miscarriage, preterm delivery, fetal growth restriction, anhydramnios and blisters in neonate). Of note, collagen XVII is predominantly expressed in the skin, but may also be present in the amniotic epithelia, placenta and amniotic fluid.
  
• One woman had two episodes triggered by spontaneous abortion (presented with urticarial rash and heavy vaginal bleeding) but had 3 normal pregnancies in between [JAAD 1/2025].

Clinical

Itching is often the first symptom. The skin lesions of PG often begin on the abdomen and include urticarial plaques, vesicles and frank bulla. It may then spread to the rest of the trunk and extremities, but is rare on the face or oral mucosa. Flares have been noted after delivery, with the resumption of menses, ovulation or beginning oral contraceptives. Approximately 20% of patients will experience premature delivery. Up to 10% of the babies will develop skin lesions due to passive transfer of antibodies. Approximately 10% of patients will develop Graves disease.

Pemphigoid Gestationis vs PUPPP

Immunoflourescence

DIF of perilesional skin shows linear deposition of C3 along the basement membrane zone. Alternatively CD4 immunohistochemistry of Formalin fixed tissue is positive in PG and negative in PUPPP. Enzyme-linked immunosorbent assay (ELISA) detects the specific antibodies (usually IgG4) against collagen XVII.

BP180 ELISA is a valuable test to differentiate PG from PUPPP as it is highly sensitive for PG, negative in PUPPP and is unaffected by the use of topical steroids which can cause a skin biopsy DIF to give a false negative result [JAAD 2017;76;560].

Treatment

Potent topical steroids (beginning for example with triamcinolone 0.1% ointment BID and increasing as needed) plus antihistamines (e.g. chlorpheniramine) may be tried initially, especially in milder cases. However, most patients require systemic steroids. Prednisone may be given, e.g. 40-60 mg/day initially, then tapered as appropriate. The dose may be increased in anticipation of a post-partum flare. Use of systemic corticosteroids does not appear to increase fetal risk, and may actually decrease it due to reduction of placental inflammation. PG typically resolves after the postpartum period. PG tends to recur in subsequent pregnancies with a trend toward increased severity and earlier onset. Rarely, the patient may go on to develop typical bullous pemphigoid.

Cyclosporin has been used in severe, resistant cases.

Additional Pictures

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