Intercellular IgA dermatosis (IgA pemphigus)--two cases illustrating the clinical heterogeneity of this disorder.

IgA pemphigus is rare but may be underdiagnosed. We describe two cases, a 50-year-old female with a pustular eruption resembling subcorneal pustular dermatosis and a 55-year-old male with a pruritic vesiculopustular eruption simulating dermatitis herpetiformis. They illustrate the clinical heterogeneity of IgA pemphigus which is likely to reflect differences in autoantigens, analogous to pemphigus vulgaris and pemphigus foliaceus. There is now evidence that IgA pemphigus encompasses at least two subgroups: a subcorneal pustular dermatosis (SPD)-type, (see case 1) characterized by subcorneal pustules and autoantibodies to desmocollin 1; and intra-epidermal neutrophilic dermatosis (IEN)-type cases (see case 2) which show intra-epidermal pustules and in whom the autoantigen may be desmoglein 3, the pemphigus vulgaris antigen.