The most common type of hair loss in women is female androgenetic alopecia (female pattern baldness). According to the International Society of Hair Restoration Surgery, it occurs in about 20 percent of American women overall.

For male hair loss, see Male Pattern Baldness.

There is an increased incidence of female androgenetic alopecia during and after menopause. 

The underlying cause of female androgenetic alopecia is believed to be related to production of androgenetic (male) hormones and the effect of androgenetic hormones on the hair follicle – the same underlying cause responsible for male androgenetic alopecia (male pattern baldness). The pattern of hair loss in female androgenetic alopecia has some distinctive features that differentiate it from male-pattern hair loss. In general, there are three patterns of hair loss in female androgenetic alopecia:

Grade I: Thinning hair on the central scalp (top of the head).

Grade II: Thinning hair and patches of greater scalp hair loss.

Grade III: Male-pattern alopecia with hair loss at the front of the scalp to mid-scalp. However, it is very rare to see complete male-pattern ‘cue-ball’ baldness in a woman.

Female hair loss occurs in more than one pattern. If you are a woman with loss of scalp hair, you should seek professional advice from a hair restoration specialist. In most cases, female hair loss can be effectively treated.

The patterns of hair loss in women are not as easily recognizable as those in men. Unlike hair loss in men, female scalp hair loss may commonly begin at any age through 50 or later, may not have any obvious hereditary association, and may not occur in a recognizable ‘female-pattern alopecia’ of diffuse thinning over the top of the scalp.

A woman who notices the beginning of hair loss may not be sure if the loss is going to be temporary or permanent — for example, if there has been a recent event such as pregnancy or illness that may be associated with temporary hair thinning.

In women more often than in men, hair loss may be due to conditions other than androgenetic alopecia. Some of the most common of these causes are:

• Trichotillomania – compulsive hair pulling. Hair loss due to trichotillomania is typically patchy, as compulsive hair pullers tend to concentrate the pulling in selected areas. Hair loss due to this cause cannot be treated effectively until the psychological or emotional reasons for trichotillomania are effectively addressed.

• Alopecia areata – a possibly autoimmune disorder that causes patchy hair loss that can range from diffuse thinning to extensive areas of baldness with ‘islands’ of retained hair. Medical examination is necessary to establish a diagnosis.

• Triangular alopecia – loss of hair in the temporal areas that sometimes begins in childhood. Hair loss may be complete, or a few fine, thin-diameter hairs may remain. The cause of triangular alopecia is not known but the condition can be treated medically or surgically.

• Scarring alopecia – hair loss due to scarring of the scalp area. Scarring alopecia typically involves the top of the scalp and occurs predominantly in women. The condition frequently occurs in African-American women and is believed to be associated with persistent tight braiding or ‘corn-rowing’ of scalp hair. A form of scarring alopecia also may occur in post-menopausal women, associated with inflammation of hair follicles and subsequent scarring.

• Telogen effluvium – a common type of hair loss caused when a large percentage of scalp hairs are shifted into ‘shedding’ phase. The causes of telogen effluvium may be hormonal, nutritional, drug-associated, or stress-associated.

Loose-anagen syndrome –a condition occurring primarily in fair-haired persons in which scalp hair sits loosely in hair follicles and is easily extracted by combing or pulling. The condition may appear in childhood, and may improve as the person ages.

For information on hair restoration, see Hair Transplant Surgery