Systemic corticosteroids are often used as primary therapy for PG, but alternatives should be considered for their favorable safety profile.
A recent case report published in the Journal of Dermatology for Physician Assistants reviewed the clinical presentations of pemphigoid gestationis (PG) and available treatment options. From their case report and discussion, Merson et al recommend quick treatment upon diagnosis and for clinicians to consider agents such as topical corticosteroids, systemic corticosteroids, antihistamines, calcineurin inhibitors, intravenous immunoglobulin (IVIG), azathioprine, dapsone, cyclosporine, and pyridoxine.
PG is a vesiculobullous autoimmune dermatosis of pregnancy with an estimated prevalence of 1 in 60,000 pregnancies, making it one of the rare causes of pruritic skin disorders during pregnancy. Multigravida women typically develop PG during their second or third trimesters, and PG does not differ among age or ethnicity.
Merson et al describe the clinical presentation of PG as the “eruption of intensely pruritic erythematous papules and plaques that begin centrally over the abdomen and may progress peripherally to flexural areas of the trunk and extremities.” In some severe cases, the lesions can become tense vesicles and bullae typical of a pemphigoid-like disease. Most patients experience lesions throughout their pregnancy, which then spontaneously resolve during postpartum.
The study authors noted the pathogenesis of PG is not fully understood, however, it may be similar to bullous pemphigoid.
According to Merson et al, “The clinical characteristics of early pruritic periumbilical erythematous urticarial papules and plaques or later progression of tense blister along with a confirmatory [direct immunofluorescence] DIF are considered to be diagnostic of PG. No data exist for biopsy with DIF or serum-based screening of patients without a characteristic rash or presentation suggestive of PG.” Fetal risks of PG include intrauterine growth restriction or preterm labor. Maternal risks include an increased risk of associated autoimmune diseases such as autoimmune thyroiditis. The study authors also wrote that there is variable data regarding the likelihood of PG occurring in later pregnancies.
Merson et al emphasized that despite the different treatment paths for PG, it is crucial to initiate treatment as soon as a diagnosis is made to reduce symptoms and prevent new lesions from forming. The choice of agent depends on the severity of the patient’s symptoms and whether the patient is pregnant or postpartum.
Merson et al wrote that a combination of topical corticosteroids and antihistaminic agents may resolve symptoms in mild cases of PG. The study authors recommend starting the patients with lower potency topical steroids and adjusting to higher potency based on the patient’s outcome. Breastfeeding patients should be prescribed second-generation antihistamines to control pruritus. Calcineurin inhibitors can also be considered on small areas of the skin if the patient does not want topical corticosteroids, or they are contraindicated with a maximum treatment of 5g/day for 2 to 3 weeks.
For moderate to severe PG symptoms, systemic corticosteroids combined with topical corticosteroids and antihistamines are needed. If the patient is pregnant, the study authors prefer prednisone over other oral corticosteroids because it is ‘metabolized by placental dehydrogenase enzymes resulting in lower levels of corticosteroid reaching the fetus.” According to the study authors, a starting dose of prednisone 0.5mg/kg/d by mouth can provide significant symptom clearance. If there is an inadequate response, the dose can be increased to 1mg/kg/day.
If a patient has an inadequate response to any of the treatments mentioned above, Merson et al recommend the use of steroid-sparing agents such as IVIG, azathioprine, dapsone, cyclosporine, and pyridoxine. Steroid-sparing agents can be used for patients with contraindications or those experiencing adverse effects of systemic corticosteroids. The study authors also wrote that in some cases, IVIG treatment has been successful for PG where prednisone was either contraindicated or ineffective.
Merson et al described a case report of a 36-year-old pregnant woman (gravida 2, para 1, 29 weeks) with a history of PG who presented with a new rash. The rash at presentation was “intensely and severely pruritic across the periumbilical area and unrelieved by topical triamcinolone 0.1% ointment or over-the-counter antihistamines, such as loratadine or diphenhydramine.” The patient also had a history of PG during her first pregnancy which began at 21 weeks gestation.
According to the report, histology and DIF showed subepidermal blisters with an infiltrate of predominantly eosinophils and a linear band of C3 with positive immunoglobulin G (IgG) at the basement membrane zone consistent with PG. The patient’s PG was treated with high-dose systemic corticosteroids which improved the severe pruritus and blisters. Despite improvement, the patient reported significant adverse effects related to corticosteroid use and wanted to avoid systemic corticosteroids during her second pregnancy. Adverse effects of systemic corticosteroids include fragile skin, slow wound healing, weight gain, moon facies (the appearance of a rounded face due to increased fluid and fat deposits within the soft tissues), difficulty sleeping, as well as premature delivery at 35 weeks with subsequent infant hypoglycemia.
Because of the aversion to systemic corticosteroids, the patient discussed alternative therapies to systemic corticosteroids with clinicians after referencing an online support group. According to the case report, the patient “reported an improvement in her mental health through the sharing of treatment options with hundreds of other people with similar presentations of PG.” Finally, the patient chose to treat her PG with IVIG due to its favorable safety and low side effect profile in pregnancy. According to the study authors, the patient’s pruritis decreased and her baby girl was delivered at 37+5 weeks gestation.
“Providers unfamiliar with pruritic syndromes of pregnancy should consider urgent referral to dermatology in a patient with an unclear presentation or diagnosis. Those practicing in a setting caring for patients with pruritus in pregnancy should be able to recognize and appropriately treat patients with PG being mindful of side effects and contraindications as a method to improve long-term patient outcomes and satisfaction,” concluded Merson et al.
Merson J, Clapp M, Shehu M. Recognition and management of pemphigoid gestationis. JDPA. 2023;17(4):35-38.