[Androgenetic alopecia]

The physiopathology of androgenetic alopecia is linked to the action of the androgens of the bulbs pilairs of the scalp. The action of these androgens can be associated with the level of hormones in circulation and with the genetic predisposition which will influence the activity of these androgens at the periphery. The classifications of the evolution of alopecia will be done following Norwood for the male and following Ludwig for the female. Hormonal investigation will be effectuated on the female only in the case of research on or the identification of hyperandrogenia; this is essential in order to direct the therapy. The diagnose and the therapeutic follow-up are essentially clinical but can be assisted by a trichogram which will show-up the miniaturisation process of androgenetic alopecia and the telogen effluvium of the affected areas. The treatment of alopecia can be local or general. The local treatment will use a lotion of minoxidil 2 to 5% whether the patient is male of female. On males, an inhibitor of the 5 alpha reductase 2, finasteride, has shown its efficiency at a dose of 1 mg/day. On females oestroprogestatives will be used, if they are not counter-advised, associated with an anti-androgen: either cyproterone acetate or spironolactone. A therapeutic evaluation will be made after 6 months of treatment.