Unlike hair loss in men, female scalp hair loss may commonly begin at any age through 50 or later and may not have any obvious hereditary association.  Women also tend to have less obvious patterns of hair loss compared to male pattern baldness.

Diagnosis of female hair loss should be made by a trained and experienced physician because there may be other medical factors contributing to the hair loss.  If not other medical factors exist, 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 same patterns that occur in men.  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.

Women with 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.