Subacute prurigo variant of bullous pemphigoid: Autoantibodies show the same specificity compared with classic bullous pemphigoid

We describe a 76-year-old white woman with a 6-month history of intensive pruritus and excoriated papules resembling subacute prurigo. Histopathology showed signs of chronic dermatitis, whereas findings by direct and indirect immunofluorescence microscopy were compatible with bullous pemphigoid (BP). The patient's serum contained IgG autoantibodies that recognized epitopes on both BP180 and BP230 by Western blot analysis of epidermal extracts. In addition, we found strong reactivity with recombinant NC16A, an immunodominant region of BP180 targeted in the majority of BP sera, whereas no antibodies against the keratinocyte-derived soluble BP180 ectodomain (LAD-1) or the recombinant intracellular domain of BP180 were detected. The patient's disease responded well to oral methylprednisolone and mycophenolate mofetil. Disease activity correlated with enzyme-linked immunosorbent assay reactivity of antibodies to BP180 but not with titers of antibodies to the dermoepidermal junction as determined by indirect immunofluorescence on salt-split skin. Our findings suggest that the subacute prurigo form of BP is a true variant of BP.