Childhood bullous pemphigoid--report of a case with dermal fluorescence on salt-split skin.

Bullous pemphigoid (BP) is an acquired bullous disorder which predominantly affects the elderly. It is rare in children, and may be clinically indistinguishable from other immunobullous disorders. As routine histology may be non-specific, a definitive diagnosis of childhood BP usually depends on the results of direct and indirect immunofluorescence investigations. We report a 5-year-old girl who developed bullous pemphigoid, associated with atypical immunofluorescence findings. Indirect immunofluorescence on split-skin showed a pure dermal pattern of IgG binding. This is usually suggestive of epidermolysis bullosa acquisita, but Western immunoblotting was positive with epidermal extracts, confirming a diagnosis of BP. Dermal binding on split-skin occurs in about 5% of adult cases of BP, and has not been reported previously in childhood BP.