26.2.1 Microscopic Hair Root Analysis

  • Microscopic hair root analysis can be a useful method for helping find certain hair-loss conditions such as alopecia areata , traction alopecia, and cicatricial alopecia.
  • Note that this method can cause confusion particularly when analyzing the anagen and telogen phases of the hair cycle:
    • An anagen root is a very pliable, soft tissue, because it contains living cells for the first two millimeters or so (one-tenth of an inch) from the papilla.  When the hair is pulled out, this tissue at the root stretches and then breaks away from the papilla, like a rubber band.  As the tissue hardens in the air and is viewed under the microscope or magnifying lens, it has an irregular look.  Also, it is often pigmented and is surrounded by a translucent (see-through) root sheath.
    • A telogen root, on the other hand, has already hardened in the hair follicle and its bulb shape doesn’t change when pulled out.  When viewed under a microscope, the area where the shaft meets the root appears regularly shaped and looks like a small bulb, often without pigment or with less pigment than the rest of the hair shaft.  This is what looks like a “plant bulb”.