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. 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.

Self-diagnosis is often ineffective. Women tend
to have less obvious patterns of hair loss than
men, and non-pattern types of hair loss are
more frequent in women than in men.
Diagnosis of hair loss in a woman should be
made by a trained and experienced physician.

In women as in men, the most likely cause
of scalp hair loss is androgenetic alopecia—
an inherited sensitivity to the effects of
androgens (male hormones) on scalp hair
follicles. However, women with hair loss due
to this cause usually do not develop true
baldness in the patterns that occur in men—
female hair loss occurs in various patterns
and is often diffuse or veiled vs bald.
Patterns of female androgenetic alopecia
can vary considerably in appearance.



Patterns that may occur include:

Diffuse thinning of hair over the entire scalp, often with more noticeable thinning toward the back of the scalp.

Diffuse thinning over the entire scalp, with more noticeable thinning toward the front of the scalp but not involving the frontal hairline.

Diffuse thinning over the entire scalp, with more noticeable thinning toward the front of the scalp, involving and sometimes breaching the frontal hairline.

Unlike the case for men, thinning scalp hair in women due to androgenetic alopecia does not uniformly grow smaller in diameter (miniaturize). Women with hair loss due to androgenetic alopecia tend to have miniaturizing hairs of variable diameter over all affected areas of the scalp. While miniaturizing hairs are a feature of androgenetic alopecia, miniaturization may also be associated with other causes and is not in itself a diagnostic feature of androgenetic alopecia. In post-menopausal women, for example, hair may begin to miniaturize and become difficult to style. The precise diagnosis should be made by a physician hair restoration specialist.

It is important to note that female pattern hair loss can begin as early as the late teens to early 20s in women who have experienced early puberty. If left untreated, this hair loss associated with early puberty can progress to more advanced hair loss if it is left untreated.