Pemphigoid gestationis.

We present a 21-year-old primigravida woman with a several-week history of pruritic, edematous, targetoid plaques that appeared initially on the abdomen, flanks, and legs and that progressed to involve the inner aspects of the upper arms and lateral aspects of the chest. The histopathologic findings showed perivascular and interstitial dermatitis with eosinophils and vacuolar changes with linear C3 deposition at the basement-membrane zone on direct immunofluorescence study. A diagnosis of pemphigoid gestationis was made. Pemphigoid gestationis is a rare, bullous dermatosis of pregnancy that may be associated with prematurity and small-for-gestational age birth weights. The diagnosis is often made with direct immunofluorescence studies of perilesional skin. Oral glucocorticoids remain the gold standard of therapy in moderate-to-severe cases. The edematous papules and plaques of pemphigoid gestationis may be particularly difficult to distinguish from polymorphic eruption of pregnancy; therefore, immunofluorescence studies are prudent. Prompt recognition and appropriate management may reduce morbidity of this disease, which often recurs with subsequent pregnancies.