Herpes gestationis (HG)¹ is a pruritic polymorphic inflammatory dermatosis of pregnancy and the postpartum period. It is an autoimmune process with circulating complement-fixing IgG antibodies in the serum. It creates severe discomfort for the affected, but it is debated whether fetal prognosis is impaired.
Causes of Herpes Gestationis
Etiology unknown. The C3 deposition at the basement membrane and HG factor suggest an immunologic mechanism similar to that in bullous pemphigoid. It is postulated that IgG antibodies arise in response to antigenic stimulus peculiar to pregnancy, perhaps in the amnion. These antibodies have specificity for a 180-kDa antigen, a hemidesmosomal peptide. Antibodies deposited on the basement membrane zone activate the complement cascade, which in turn generates an inflammatory response.
Relationship between HG and bullous pemphigoid is unresolved. This relationship is suggested by the morphologic similarity of lesions, similar immunopathology, and the fact that the HG antigen is very closely related to, if not identical with, the 180-kDa bullous pemphigoid antigen.
Hormonal factors undoubtedly play an important role. Onset in pregnancy or thereafter, postpartum flares, and exacerbations with hormone-producing tumors or contraceptives.
Symptoms of Herpes Gestationis
- Initially there are itchy red bumps around the belly button.
- Some patients may have no blisters but instead have plaques (large raised patches)
Diagnosis
Clinical setting confirmed by histology and immunofluorescence.
Treatment
Systemic glucocorticoids given orally in doses equivalent to 20 to 40 mg of prednisone. Exacerbation during remission may require higher doses. Prednisone is gradually tapered during the postpartum period. A few patients do not require systemic prednisone and can be controlled with antihistamines and topical steroids.
Infants born to affected mothers who have received high doses of prednisone should be examined carefully by a neonatologist for adrenal insufficiency. Cutaneous lesions in infants are transient and do not require therapy.
References