[Seasonal variation of trichogram in Chilean subjects].
BACKGROUND
Human hair follicle experiments cyclical transformations throughout its life. These are rest (telogen phase), growth (anagen phase) and regression mediated by apoptosis (catagen). During summer the percentage of telogen increases and the percentage of anagen decreases.


OBJECTIVE
To determine the seasonal changes of scalp hair follicle phases among Chilean subjects.


METHODS
Retrospective analysis of 514 differential trichograms of normal scalps from subjects aged 36+/-14 years, obtained between 1998 and 2008.


RESULTS
During summer and winter, the mean percentage of telogen was 20%+/-10% and 16%+/-10%, respectively (p <0.01). The figures for anagen in the same periods were 80%+/-10% and 83%+/-10%, respectively.


CONCLUSIONS
This study confirms the presence of seasonal variations in normal trichogram.
Kahn Ch
Mariana
M
Servicio de Salud Metropolitano Norte, Santiago, Chile. marianakahnchernilo@hotmail.com
Guerrero A
Robinson
R
Césped
María Cristina
MC
D000328:Adult; D002677:Chile; D005260:Female; D018859:Hair Follicle / Q000254:growth & development*; D006801:Humans; D008297:Male; D012189:Retrospective Studies; D012535:Scalp / Q000502:physiology*; D012621:Seasons