Direct immunofluorescence diagnosis of pemphigus without biopsy

Background: Direct immunofluorescence (DIF) is a necessary examination tool for the diagnosis of pemphigus. The suction-blister-method splits the skin at the lamina lucida and it is possible with a scalpel to separate the entire epidermis from the dermis. Objective: The study was to determine whether DIF is reliable on epidermal sheets separated using a suction apparatus. Methods: Thirteen patients were selected for this study: (nine with pemphigus vulgaris (PV), one with paraneoplastic pemphigus (PP), and three with pemphigus erythematosus (PE). Frozen epidermal sheets, separated from the dermis with a scalpel, were used as a substrate. Diagnosis with routine fluorescein isothiocyanate (FITC) antibodies was made. Results: In all patients a pericellular deposition of IgG was evident and in eight of these patients a pericellular deposition of C3 was present. In two cases of PE and one of PP, the C3 deposits were also present in the lower part of basal keratinocytes. Conclusion: This diagnostic method without skin biopsy is easy to perform and, together with the histology and clinical aspects, could be a useful tool in the diagnosis of pemphigus. We recommend this method when the patient is allergic to local anaesthetics, the patient easily produces hypertrophic scars, or in follow-up of already biopsied patients.