Value of direct immunofluorescence for differential diagnosis of cicatricial alopecia.

BACKGROUND There are diverse causes of cicatricial alopecia characterized by lack of follicular ostia and irreversible loss of hair. While clinical differentiation between the causes may be difficult, particularly with regard to lichen planus (LP), lupus erythematosus (LE) and pseudopelade of Brocq (PB), it has been suggested that both histopathologic examination and direct immunofluorescence studies (DIF) are necessary for an accurate diagnosis. OBJECTIVE The aim of this study was to evaluate the diagnostic value of DIF studies in addition to histopathology in patients with cicatricial alopecia as a clinical feature. METHODS 136 scalp biopsy specimens received for histopathology and DIF during a 5-year period were reviewed. RESULTS Definitive diagnosis was achieved by careful evaluation of scalp biopsies. The most prevalent diagnoses in order of frequency were LP (26%), LE (21%) and folliculitis decalvans (20%). PB was diagnosed in 10%. In most cases, the diagnosis could be made on the basis of histopathology and independently of DIF. Characteristic DIF patterns showed high specificity, but low sensitivity for LP, and high specificity and sensitivity for LE. The DIF pattern in PB showed no difference to LP. CONCLUSIONS Histopathology permits diagnosis in the majority of cicatricial alopecias. DIF is of value in histopathologically inconclusive cases, particularly when LE is in question.