Direct immunofluorescence of the hair follicle in pemphigus: a less invasive method for diagnosis

Abstract

Background Demonstration of intercellular deposition of immunoglobulin (Ig)G on the cell surface of keratinocytes by direct immunofluorescence (DIF) of the skin is the gold standard in diagnosis of pemphigus. In the past few years, the intercellular deposition of IgG in the outer root sheath has shown to be useful. Objective The aim was to compare the DIF of hair (plucked anagen and telogen and telogen obtained by combing) with that of skin for diagnosis of patients with pemphigus vulgaris (PV) and those with pemphigus foliaceus (PF). Materials and methods A total of 30 patients [24 with PV and six with PF] with active disease were included. Clinical evaluation (ABASIS score), histopathological examination, and DIF of skin and hair were done. Presence of intercellular deposits of IgG and or C3 in skin and outer root sheath of the hair was considered positive. Results DIF of skin was positive in all patients for IgG and in 25 patients for C3 and also DIF in anagen hair was positive in all patients, whereas in telogen hair, it was positive in 23 patients (17 with PV for both IgG and C3, and six with PF for IgG, and four of them for C3). All patients showed a positive relation between clinical, histopathological, DIF skin, and DIF of anagen hair in both PV and PF. Regarding telogen hair, the same findings was found in all six (100%) patients with PF, but in PV, only 17 (70.83%) patients showed these positive relations, whereas the other seven (29.2%) had positive DIF of both skin and anagen hair only. The sensitivity of hair DIF was 100% for anagen hair and 76.67% for telogen hair in patients with pemphigus. Conclusion Anagen and telogen hair DIF is a simple, noninvasive, and cost-effective procedure and can be used as an additional procedure for diagnosis in patients with PV and PF.