Genetic hair loss in women

In women, there’s a distinct relationship between mother, sisters, aunts, and grandmothers when it comes to thinning hair patterns. When we take a careful history from women with thinning hair, far more than half of the women we interview with balding or thinning have female relatives with a similar problem. When one recognizes this in the family history, we generally ask these women to inquire on the course of the family balding patterns from a timeline perspective.

Genetic hair loss is relatively uncommon in women and is generally referred to as female pattern hair loss or female androgenetic alopecia. In women with this condition, the common pattern differs than that of men. Whereas the pattern in men follows the Norwood classification, the postmenopausal pattern in women is characterized by diffuse thinning starting just behind a normal hairline and extending to and beyond the swirl.

Unlike men, adult women with typical female postmenopausal androgenetic alopecia often have significant levels of miniaturization (decreased hair shaft thickness in some hairs and loss of hairs within the follicular unit) in the back and side of the scalp.

Miniaturization causes hair shafts to become thinner over time before falling out, and the higher degree of miniaturization present indicates an unstable hair loss process throughout the scalp. In some women, the genetic pattern of hair loss is associated with an increase in male sex hormones (androsterone, testosterone, and DHT), but in most cases of genetic hair loss, it occurs when the sex hormone levels are normal.

Compared to men, the mechanism of balding in women is less well understood because their hair loss isn’t as directly related to the presence of DHT. The enzyme aromatase appears to have a role in causing female hair loss and may partially explain the different pattern when compared to men. The loss of estrogens in postmenopausal women means that the protection against female genetic alopecia is withdrawn, bringing on the thinning.

Women who develop pattern balding later in life also have a genetic component to their hair loss, but the association is less strong. The changes in hormones that occur around menopause are an obvious contributing factor.

Because genetic hair loss presents itself differently in women than in men, a different classification system is used. Doctors use the Ludwig classification to describe the thinning that women experience. A Ludwig type I is associated with a mild widening of the part width. Patients who fall into type II have increased thinning with moderate widening of the part. Type III patients have significant widening of the part width. Figure 4-3 depicts types I through III. A minority of women develop pattern balding in a distribution that’s similar to men.

These patients are better classified using the Norwood classification system. Because these women have hair loss mainly limited to the front and top of the scalp that doesn’t affect the back and sides, they may be candidates for hair transplant surgery. About 15 percent of women have this patterned balding.