Regulation of hair follicle cycle]

This review is devoted to the control of hair growth. The hair follicle undergoes cyclic transformation from the resting phase (telogen) to the growth phase (anagen). The latter phase is characterized by rapid proliferation of follicular keratinocytes and elongation and thickening of the hair shaft. The regression phase (catagen) leads to the involution of the hair follicle. These cyclic changes include rapid remodeling of both the epithelial and the dermal components. They are controlled by numerous different factors: sex hormones, neurotrophins, FGF, TGF, BMP, VEGF, Sonic Hedgehog, and other signaling pathways.