Acquired epidermolysis bullosa
This can also look like pemphigoid, but has two im-portant extra features: many of the blisters are a response to trauma and arise on otherwise normal skin; and milia are a feature of healing lesions. The target of the autoantibodies is type VII collagen in anchoring fibrils (see Fig. 9.5). The antigen lies on the dermal side of the lamina densa, in contrast to the pemphigoid antigens, which lie on the epidermal sideaa difference that can be demonstrated when the basement membrane is split by incubating skin in a saline solution (the ‘salt-split’ technique). The condi-tion responds poorly to systemic corticosteroids or immunosuppressive agents.