Floor-pattern salt-split skin cannot distinguish bullous pemphigoid from epidermolysis bullosa acquisita. Use of toad skin.

BACKGROUND AND

DESIGN

Patients with epidermolysis bullosa acquisita (EBA) and bullous pemphigoid (BP) can present with similar clinical features. These antigens have different phylogenetic origins. It was thought that sodium chloride split-skin immunofluorescence could reliably distinguish between BP and EBA. However, it has now been recognized that both diseases can present with a floor pattern fluorescence on salt-split skin. A simple method is required to distinguish these diseases.

RESULTS

Serum specimens from two patients presenting with pruritic blisters showing a floor pattern immunofluorescence on salt-split skin were found to have positive fluorescence on toad skin that has the BP and not the EBA antigen. The diagnosis of BP in these patients was confirmed by a prompt response to treatment with systemic steroids. Electron microscopy showed a split at the lamina lucida.

CONCLUSIONS

Bullous pemphigoid can present with a floor pattern immunofluorescence on salt-split skin. The use of the skin from invertebrates like the toad may help in distinguishing BP from EBA.