Hair loss can result from many factors including thyroid disease, high fever, childbirth and certain medications.
The hair loss in this latter case is temporary and will recover within a few months.
The most common form of scalp hair loss is androgenetic alopecia (male and female pattern hair loss).
Hair loss can also be permanent.
Male pattern hair loss is determined by a combination of heredity and male hormones called androgens which include testosterone and dihydrotestosterone (DHT).
The tendency for male and female pattern hair loss is genetically inherited from either side of the family and begins to develop after puberty.
32 year old Man
Receding hair line
28 year old Man
Alopecia in the crown area
Hair on the scalp that is genetically affected by androgens (generally the front and top) will gradually be lost, whereas hair at the back and sides of the scalp is permanent because it is not affected by DHT.
An 8 stage classification of male pattern baldness was established in the nineteen fifties by the American James B. Hamilton.
32 year old Man
28 year old Man
Hamilton classification
