Common baldness, male-pattern hair loss, genetic hair loss and androgenetic alopecia are terms that   are used to describe the same thing - the hair loss typically seen in men, where hair is lost in the front, top, and crown of the scalp, but maintained on the back and sides. Female-pattern hair loss refers to the most common presentation seen in women and tends to be diffuse (thin all over).

The diagnosis of androgenetic alopecia in men is generally straightforward. It is made by observing a "patterned" distribution of hair loss (i.e. hair loss that affects the front, top and crown) and by noting the presence of miniaturized hair in the areas of thinning. Miniaturization, the progressive decrease in hair shaft diameter and length, can be identified using an instrument called a densitometer and is seen only in genetic balding. The diagnosis of male pattern hair loss is supported by the progression of the hair loss according to a recognizable pattern and by a history of baldness in the family, although a family history is not always present.
In women, the diagnosis is more complex, as the most common presentation, a diffuse pattern, can have a variety of non-androgenetic causes including pregnancy, gynecologic problems, birth control pills, and thyroid disease. Because underlying medical conditions can produce hair loss that can closely mimic the diffuse pattern seen in genetic hair loss, a careful diagnostic evaluation is particularly important.
This section helps you to understand the causes of hair loss in men and women, how hair loss is classified, and how the diagnosis of androgenetic hair loss is made.
If you would like to learn more about hair, how it grows and its function, go to: 

• Hair Anatomy
• Functions of Hair
• Hair growth and hair cycle