From the Guidelines
Female pattern hair loss is primarily caused by the miniaturization of hair follicles, driven by a combination of genetic, hormonal, and aging factors, particularly the influence of androgens on hair follicles. The pathogenesis of female pattern hair loss involves a complex interplay of these factors, leading to the transformation of terminal hairs into smaller, thinner vellus hairs 1. This process is influenced by androgens, particularly dihydrotestosterone (DHT), which is converted from testosterone by the enzyme 5α-reductase. In genetically susceptible women, hair follicles become increasingly sensitive to normal androgen levels, leading to progressive follicular miniaturization.
Some key factors contributing to female pattern hair loss include:
- Decreased estrogen levels, especially during menopause
- Insulin resistance
- Inflammation
- Oxidative stress
- Environmental factors
- Certain medical conditions like polycystic ovary syndrome, thyroid disorders, and iron deficiency can exacerbate female pattern hair loss, as noted in the context of endocrine therapies causing hair changes 1.
The hair cycle is also affected, with shortened anagen (growth) phases and prolonged telogen (resting) phases, resulting in fewer actively growing hairs and increased shedding. This multifactorial pathogenesis explains why treatment approaches often target hormonal pathways, stimulate follicular growth, and address underlying medical conditions. Unlike the hair loss patterns associated with chemotherapy or endocrine therapy-induced alopecia, female pattern hair loss typically presents with diffuse thinning across the central scalp while maintaining the frontal hairline 1.
From the Research
Pathogenesis of Female Pattern Hair Loss
- Female pattern hair loss (FPHL) is a common form of alopecia in women, characterized by progressive loss of terminal hairs 2, 3, 4, 5, 6
- The condition is often associated with psychological distress and impaired social functioning 2, 3, 4, 6
- The pathogenesis of FPHL is not fully understood, but it is believed to be an androgen-dependent condition, at least in the majority of cases 3, 4
Role of Androgens in FPHL
- The response to oral antiandrogens suggests that FPHL is an androgen-dependent condition 3
- Androgens play a role in the miniaturization of hair follicles, leading to the characteristic pattern of hair loss seen in FPHL 3, 4
- The use of anti-hormonal therapy, such as cyproterone acetate and spironolactone, has been shown to be helpful in treating FPHL in some women with normal hormone levels 4
Hair Follicle Miniaturization
- The miniaturization of hair follicles is a key feature of FPHL, leading to the replacement of terminal hairs with vellus hairs 2, 3, 4, 5, 6
- The process of hair follicle miniaturization is not fully understood, but it is believed to be influenced by a combination of genetic, hormonal, and environmental factors 6
- Treatment of FPHL aims to reverse or stabilize the process of hair follicle miniaturization, with topical minoxidil being the only medication with a high level of evidence for its effectiveness 6
Treatment Challenges
- Treatment of FPHL is often challenging, with many therapeutic options having a limited level of evidence and not meeting patient expectations 6
- The lack of knowledge of the pathogenesis of the hair miniaturization process and the factors that regulate follicular morphogenesis restricts the prospect of innovative therapies 6
- There is a need for randomized, controlled studies with longitudinal follow-up, using objective outcomes and exploring the performance of available treatments and their combinations 6