The recognition of early stages of catagen.
Several criteria for recognition of follicles in catagen have been advanced, namely, loss of metachromasia in the hair papilla, subsidence of mitotic activity there, retraction of the lower portion of the follicle, and thickening and corrugation of the fibrous root sheath. The presence of scattered apoptotic cells in the outer root sheath is an additional marker of early catagen.
D000505:Alopecia / Q000473:pathology / Q000503:physiopathology; D000818:Animals; D006197:Hair / Q000254:growth & development* / Q000648:ultrastructure; D006801:Humans; D051379:Mice; D014256:Trichotillomania / Q000473:pathology / Q000503:physiopathology