Demonstration of pemphigus-specific immunofluorescence pattern by direct immunofluorescence of plucked hair

Background: Direct immunofluorescence (DIF) of perilesional skin is the gold standard in the diagnosis of pemphigus. Since the outer root sheath (ORS) of anagen hair is structurally analogous to epidermal keratinocytes, pemphigus specific immunofluorescence pattern may be present in the ORS. Methods: Twenty consecutive patients of pemphigus were enrolled in the study, irrespective of any other inclusion or exclusion criteria. Hairs were plucked in a similar fashion to that of trichogram. Approximately 5 anagen hairs were selected processed and stained with fluorescein isothiocyanate (FITC) conjugates. DIF of perilesional skin and indirect immunofluorescence (IIF) were carried out simultaneously. DIF of hair was also done in equal numbers of controls with other dermatoses. Results: Intercellular deposition of IgG was seen in the ORS of anagen hair in 85% of patients (n = 17). The test was positive in all patients who had scalp lesions (n = 10); however, it was also positive in 7 patients (77.7%) who did not have scalp lesions. The test was negative in 3 patients; two of whom were elderly and had sparse scalp hair. The other patient only had mucosal lesion. The test was negative in the control group. Conclusion: DIF of hair is a simple, non-invasive test. In future, it may alleviate the need for skin biopsies, in patients with pemphigus.