Direct immunofluorescence of the outer root sheath in anagen and telogen hair in pemphigus vulgaris and pemphigus foliaceus.

Direct immunofluorescence of peri-lesional skin is the gold standard in the diagnosis of pemphigus. A specific immunofluorescence pattern may also be demonstrated in the outer root sheath of anagen and telogen hair. We demonstrated an intercellular reticular deposition of immunoglobulin G in the outer root sheath of plucked anagen and telogen hair in all pemphigus vulgaris patients with active disease and for the first time in all patients with active pemphigus foliaceus. Moreover, we demonstrated for the first time that plucked hair samples may be kept at -20°C for at least 2 weeks before immunofluorescent staining and analysis.