Immunohistologic and ultrastructural comparison of the dermal papilla and hair follicle bulb from "active" and "normal" areas of alopecia areata.

The "active" edges of patches of alopecia areata and normal areas from the same scalp (i.e., bearing normal terminal hair) from seven patients with alopecia areata were investigated immunohistologically. Similar areas from a further eight patients were examined using light and electronmicroscopy. "Active" and "normal" areas of alopecia areata scalps were immunohistologically similar and varied from normal controls in the number, distribution, and ratio for T4 and T8-positive cells. Similarly the ultrastructural changes seen in the "active" areas when compared to normal controls were also present in the "normal" areas of alopecia areata scalps. The most significant differences found between normal "control" follicles and both "active" and "normal" areas of alopecia areata scalps were the polymorphic nature of the dermal papilla cells and the loss of cellular organization within the dermal papillae taken from alopecia areata scalps. In addition, the junction between the dermal papilla and the bulb of the hair follicle, the dermo-epithelial junction of the hair follicle bulb, demonstrated critical changes in follicles taken from both "active" and "normal" areas of alopecia areata scalps. These results support the suggestion of a subclinical state of alopecia areata and indicate that further work on the etiology of alopecia areata should be directed towards the "normal" areas of alopecia areata scalps, in particular the cells of the dermal papilla and the dermo-epithelial junction of the hair follicle bulb.