Linear IgA bullous dermatosis of adults

Abstract

The skin disorder designated as linear IgA bullous dermatosis (LABD), identified in 1979 (l), had been for many years a matter of controversy. This controversy was due mainly to its clinical diversity, as some cases closely resemble dermatitis herpetiformis (DH), some cases are indistinguishable from bullous pemphigoid (BP), and still other cases combine features of both (2). No wonder that some authors considered this disease as DH or its variety (3 6), others as BP (7,8), and yet others as intermediate or mixed forms of DH and BP (2,9). In support of the relationship with DH were the skin immune deposits of immunoglobulin A (IgA) class and, as a rule, a dramatic response to sulfones. Supporting the relationship with BP were the linear pattern of IgA deposits along the basement membrane zone (BMZ) and, occasionally, the concomitant presence of complement in the same distribution (1,2,9). Furthermore, at least in some cases, the ultrastructural depositions of IgA, in the lamina lucida, similar to that in BP, suggested some relationship between LABD and BP (10 12). In a proportion of cases of LABD, the linear IgA deposits are found below the basal lamina (12-14) or in both locations (6,11,12,15). The main difference from BP is the IgA-class skin deposits, papillary microabscesses in the histology, and, as a rule, a good response to sulfones. The most important reason for separation of LABD from DH is that LABD is not associated with gluten-sensitive enteropathy and, as could be expected, a glutenfree diet is not effective treatment for LABD (16). Recognition of LABD as a distinct entity, despite the clear-cut differences from DH and BP, took a long time until more data on immunoelectron microscopy, serology, genetics,