Female pattern hair loss is the most common type of alopecia in women. The prevalence of this condition increases with age, affecting almost 40% of women aged 70 years or older. Female pattern hair loss is a type of diffuse, nonscarring alopecia, characterized by shortening of the hair growth phase, follicular miniaturization, and conversion of thicker terminal hairs to shorter and finer vellus hairs. Patients typically report a gradual and progressive hair loss, localized to the bitemporal areas and the central scalp. Beyond its physical effects, female pattern hair loss significantly impacts quality of life. Studies have shown decreases in quality of life and self-esteem in women with female pattern hair loss compared with unaffected women.
On examination, women with female pattern hair loss appear to have a normal scalp, without evidence of inflammation or scarring; follicular orifices are present. Hair loss occurs in a typical pattern, with widening of the central part, thinning at the crown, and sparing of the frontal hairline. The "hair-pull test" may be used to differentiate female pattern hair loss from other types of diffuse, nonscarring alopecia. During this test, the clinician firmly grasps 40–60 hairs at their base and gently pulls away from the scalp. A positive test result occurs when more than three hairs are removed with each pull at different scalp locations, and is suggestive of alternative diagnoses, such as telogen or anagen effluvium or alopecia areata.
There are no specific laboratory abnormalities associated with female pattern hair loss; most women will have normal serum testosterone levels. However, clinicians should perform testosterone, dehydroepiandrosterone sulfate (DHEAS), and prolactin testing in any patient presenting with female pattern hair loss and other signs of hyperandrogenism, such as hirsutism, virilization, or severe acne. Diffuse hair loss may also be seen in patients with low iron levels, nutritional deficiencies, and thyroid disease; testing for these abnormalities may be appropriate in certain individuals. Patients with a previous history of polycystic ovary syndrome have increased rates of female pattern hair loss.
The goals of treatment are to slow hair loss and to stimulate new hair growth. Topical minoxidil is currently the only medication that is FDA-approved for the treatment of female pattern hair loss. Twice-daily application of topical minoxidil 2% solution increases hair growth and is well-tolerated. Noticeable improvement may require at least 6–12 months of therapy, and hair loss will resume if the medication is stopped. Treatment should be avoided during pregnancy and lactation. Side effects of minoxidil include facial hypertrichosis and dermatitis. Data support adjunctive therapy with spironolactone for patients who have inadequate response to minoxidil alone. However, they must tolerate moderate doses (100–200 mg) of spironolactone. Side effects of spironolactone include orthostatic hypotension, hyperkalemia, decreased libido, and menstrual irregularities; it also must not be used by patients who are pregnant or lactating. In postmenopausal women with female pattern hair loss, small trials support the use of finasteride, the oral 5-alpha–reductase inhibitor effective for the ...