Epithelial skirt and bulge of human facial vellus hair follicles and associated Merkel cell-nerve complex.

Abstract

Many morphological variations of bulge areas, such as knob-like swellings, were found in extracted human facial vellus hairs. In anagen vellus hair of the face bulge areas including these knobs had a band-like dense aggregation of CAM5.2 (K8, 52.5 kDa) reactive Merkel cells. In telogen hair the bulge became indistinguishable from the clubbed or regressed end of the follicle but Merkel cells continued to be abundant. The epithelial hood at sebaceous gland level showed most commonly a skirt-like structure but variations were also observed; these were bamboo joints, tulip flower, and long apron configurations. Merkel cells were found sparsely in these structures. Palisading stockade-like nerve endings were observed surrounding the follicular epithelium under the skirt and around the bulge areas including the knobs. Merkel cells were sparse in the follicular segment corresponding to the attachment of stockade nerve endings.