Androgenetic alopecia (pattern hair loss)
AGA or pattern hair loss is the most common hair loss in men and women. Clinical characteristics include a reduction of terminal hair density on the scalp that follows a typical pattern in both genders, with a conversion of terminal to vellus-like hairs and an increase of telogen hair (in an episode of active shedding).
Male pattern hair loss results from a combination of androgen and genetics. Its pattern will develop with recession of the frontal hairline to M-shaped and can be classified by Norwood-Hamilton classification. Ethnic variation in the incidence has been reported. Caucasian has higher incidence than Asian and African.
Female pattern is age-related. 40% of Caucasian women have developed some degree of this hair loss at age 70 but less frequent in Asian women, presented with a diffuse loss of hair on the crown and persistence of the frontal hairline.
Patient history and physical exam usually give a definite diagnosis. In young women, further investigations are recommended to rule out other diseases.
Currently, two medications are approved for the treatment of AGA: oral finasteride and topical minoxidail. However, hair restoration or hair transplantation is the most successful and permanent treatment for AGA.