Pemphigoid gestationis (also known as herpes gestationis) is a rare autoimmune skin disease characterized by severe itching and blistering that occurs exclusively during pregnancy. ICD-10 code O26.4.
The prevalence of the disease is consistent worldwide and is estimated to be 1 in 60,000 pregnancies. Pemphigoid gestationis occurs primarily during the 5th to 6th month of pregnancy, particularly during the second and third trimesters. Rarely, it may occur earlier, around the 3rd to 4th month, or after delivery. Once developed, the dermatosis may recur with each subsequent pregnancy. It often flares up after delivery, but gradually resolves within a few weeks or months, even without treatment. In some cases, the condition resolves after childbirth, but it may persist for several years.
The exact pathogenesis is not fully understood, but there is an association with HLA-DR3 in 61-80% of cases and with HLA-DR4 in 52-53% of cases. The primary immune response occurs in the placenta. Circulating IgG antibodies react with the amniotic epithelium of the placental tissue and the basal membrane of the skin. Autoimmune reactions in the skin are associated with the accumulation of immune complexes, complement activation, chemotaxis, and eosinophil degranulation, leading to tissue damage and blistering. The main triggering factor remains unclear, but it is believed that an alloimmune or autoimmune reaction is associated with deviations from the normal expression of the TI antigen of the major histocompatibility complex.During the pre-bullous stage, the patient's general condition worsens for no apparent reason. They may experience a rise in temperature, itching, burning and pain. After a few days, intensely pruritic polymorphic eruptions appear in the peri-umbilical area. These eruptions consist of erythematous, papular, vesicular, and bullous elements and are predominantly located on the abdomen and extremities. The eruptions tend to cluster.
In some patients, the disease becomes generalized. Herpes gestationis is characterized by the development of erythematous-urticarial patches on the trunk and extremities, followed after some time (2-3 days) by tiny, conical or oval, vesicular or bullous elements. The blisters may fuse, rupture, and their contents dry to form crusts. Less commonly, blisters with firm margins and serosanguineous or hemorrhagic contents may appear on an erythematous background.
At the peak of the disease, the picture is quite varied: erythematous lesions with multiple herpetiform vesicular-bullous and pustule-like elements, some of which are covered with serosanguineous crusts. Hyperpigmented patches are seen in the areas of the former blisters. The blisters contain an increased number of eosinophils, accompanied by a rise in temperature. The rashes dissolve and reappear as separate eruptions. Rashes on the mucous membranes are extremely rare.
As a result of transplacental transfer of IgG antibodies from the mother to the fetus, about 10% of newborns may develop vesicular or urticarial eruptions that resolve spontaneously within a few days to weeks.
- Subcorneal Pustulosis
- Bullous Pemphigoid
- Pruritic urticarial papules and plaques of pregnancy (PUPPP)
- Pemphigus vulgaris
Treatment of herpes gestationis can often be complex, especially if the outbreaks continue for a long time, including after childbirth. Sulfonamides, B vitamins, and antibiotics are used with caution.
For severe and persistent forms of the disease:
- Glucocorticoid therapy (prednisone at a dose of 0.5 mg/kg, with a gradual tapering to a maintenance dose depending on the disease activity). In all cases of glucocorticoid administration, consultations with obstetricians-gynecologists and neonatologists are necessary.
- Cyclosporine, dapsone, azathioprine, or methotrexate (after childbirth).
Topical treatments may include aqueous solutions of aniline dyes, antiseptics, creams and ointments containing glucocorticoids (class III and IV) and antibiotics.
Termination of pregnancy is indicated if the disease progresses.
The prognosis is generally good in most cases.