INTRODUCTION
Pemphigoid gestationis (PG) is a rare autoimmune vesiculobullous
dermatosis of pregnancy that causes intense pruritis and discomfort. It is also associated with several adverse fetal outcomes, including preterm delivery, low birth weight, and small for gestational age (SGA) infants.1,2 In 3% to 10% of cases, the neonate is directly affected.2,3,4 As a result, recognition is critical, as appropriate pharmacotherapy helps alleviate symptoms and may reduce fetal risk.
CASE
A 42-year-old woman presented to her obstetrician at 22 weeks gestation with complaint of intermittent, pruritic, and erythematous papular rash localized to the umbilicus. Despite oral antihistamines, the rash worsened, coalescing into large, urticarial patches and plaques that spread to the extremities, chest, back, and neck. At 26 weeks, blister formation prompted dermatology referral.
The patient’s condition was excellent and her past medical history was unremarkable. Physical exam revealed annular pink plaques with central clearing on the abdomen, arms, and legs that did not spare the umbilicus (Figure 1a). Plaques on the extensor extremities vesiculated into tense, fragile bullae. No facial or mucous membrane involvement was present.
Although the patient was initially diagnosed with pruritic urticarial
papules and plaques of pregnancy (PUPP), new bullae suggested a vesiculobullous disorder. Therefore, a 4 mm punch
biopsy was performed on an active lesion, and a serum immunoassay
for BP180 antibody was ordered. Pending results, we recommended topical steroids in the form of clobetasol (Clobex®) 0.05% spray. Given the degree of discomfort, we also recommended prednisone at 0.5 mg/kg/day, which she declined.
At one-week follow up the patient had not used the topical steroid,
and both rash and pruritis had worsened (Figure 1c). The rash, then covering all areas below the neck, formed numerous tense bullae. Some vesicles were covered with yellow and hemorrhagic crust (Figure 1b). Biopsy revealed eosinophilic-rich spongiotic and perivascular dermatitis at the dermal-epidermal junction (Figure 2), which strongly suggested PG. This was supported by serum immunoassay, which returned a BP180 autoantibody level of 62U/mL (normal reference range: <15U/mL). With a definitive diagnosis
of PG and given her worsening condition, oral prednisone 1 mg/kg/day was started. Oral Keflex 500 mg twice daily for 5 days was prescribed to treat the impetiginization of her lesions. The patient was advised to continue topical steroids. Expectations of disease course and fetal risks were reviewed. She was encouraged
to inform her pediatrician of her steroid regimen should fetal monitoring be needed after delivery.
After 10 days of prednisone 60 mg/day, the rash stopped spreading
and pruritus improved, so dose was decreased to 40 mg. At next follow up, there were no new vesicles or bullae. The dose was decreased to 20 mg/day over the next 2 weeks, after
which her pruritis subsided completely and, absent mild
