Massive lymphocyte-mediated apoptosis during the early stage of pseudopelade.

The early evolving lesions of the hair follicles are described in pseudopelade, a type of cicatricial alopecia where clues for the diagnosis of lupus erythematosus or lichen plano-pilaris are lacking. A sudden and synchronized cell death of all the cells of the epithelial sheaths of the hair follicles occurs and is associated with a dense infiltration by lymphocytes. The epidermis remains uninvolved. This unique aspect is most probably related to the mechanism of apoptosis. Its intensity and extension are much more pronounced than in lichen planus and in lupus erythematosus. Pathogenesis of at least some cicatricial alopecias could therefore be related to massive apoptosis without evident and close relationship with the classical etiologies, i.e. lichen planus and lupus erythematosus.