Cellular Activity in the Dermis Surrounding the Hair Bulb in Alopecia Areata

The study investigated the metabolic activity of cells in the connective tissue surrounding the hair bulb in cases of alopecia areata compared to normal scalp. Using radioautography, it was found that in alopecia areata, hair bulbs were halted at the anagen IV stage, with reduced DNA, RNA, and protein synthesis. Cells in the papilla and cellular infiltrate showed low metabolic activity. During hair regrowth in alopecia areata, endothelial cell activity increased in the papillary and peribulbar layers before the restoration of DNA, RNA, and protein synthesis in the hair bulb's epithelial cells. Eventually, the dermal and epithelial labelling patterns reached levels similar to those in a normal scalp's anagen IV stage. The study concluded that the transition from anagen IV to a further stage is critical for hair growth and relies on the metabolic function of the connective tissue, which was impaired in alopecia areata.