Hair loss is separated into two categories. Cicatricial alopecia, characterized by inflammation that permanently damages the hair follicle, is uncommon. In clinical practice, noncicatricial types make up the majority of cases of alopecia. Whereas male pattern hair loss is largely hereditary and attributable to androgenic mechanisms, less than half of women experiencing hair loss have genetic origins as the cause. The remaining cases are attributable to a range of causes, some of which may indicate an underlying illness.

Hair Loss in Women

Female pattern hair loss (FPHL), or nonscarring alopecia, is one of the most common reasons women seek dermatology consults.1,2  Hair loss is upsetting at any age and often produces significant psychological distress and loss of self-esteem that can affect daily life. In a survey of Australian women 40% reported marital problems related to hair loss and 64% said their hair loss contributed to problems at work.3


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FPHL is a progressive, nonscarring disorder in which miniaturization of the hair follicle occurs. The hair shaft gradually transforms from a thick, terminal strand into a villous strand that is short, thin, and nonpigmented.3

An estimated 49% to 55% of women over the age of 70 years, experience this form of hair thinning and stunted growth.1,3 It is more common to White women compared with those of Korean, Asian, or African American ethnicity.1,3 A genetic component has been demonstrated in 40% to 54% of patients, particularly those with earlier onset.2

The pathophysiology of FPHL is not entirely understood, although a hormonal component is suggested by the occurrence of a first onset which often during reproductive years with a second peak following menopause. Some evidence suggests that in FPHL, the follicle has a shortened growth cycle and may be lost earlier than normal.1

Several risk factors for FPHL have been identified, including increasing age, family history, smoking, elevated fasting glucose levels, and ultraviolet light exposure of more than 16 hours/week.3

But physical consequences are possible as well. Associations with insulin resistance and atherosclerosis have not been fully established, but FPHL is considered a marker for increased risk for cardiovascular and metabolic diseases.1,3 In women of childbearing years, a diagnosis of FPHL is associated with underlying hypertension, and in those women over age 50 years it is suggestive of coronary artery disease.3

Diagnosis

The hair-growth cycle has 3 main phases: growth (anagen), transition (catagen) and resting (telogen).1 The growth phase in a healthy younger individual lasts an average of 2 to 8 years, with most of the hair in this part of the cycle at any given time.

The clinical signs of FPHL are increased shedding of hair at the top of the head, which is often confused with normal periods of heavy shedding associated with life stressors. According to the American Academy of Dermatology, people normally shed between 50 and 100 hairs daily from the head and other parts of the body.4 Shedding more than 100 hairs per day is diagnosable as a temporary condition, telogen effluvium, the causes of which are generally related to stressors that upset the delicate physiology of the body, such as:

  • Recently having given birth
  • Ceasing hormonal birth control
  • Experiencing significant stress (caring for a loved one who is sick, going through a divorce, losing a job)
  • Recent high fever
  • Surgery

Hair shedding frequently occurs about 2 months following a stressful event, peaking at 4 to 5 months. It is considered a normal response and typically self-resolves within 6 to 9 months to normal hair growth.

Grading FPHL

The Sinclair scale is preferred for grading FPHL, as it provides a simple visual guide to assessing the spread of the frontal mid-central part in the hair1:

  • Grade 1: minimal thinning
  • Grades  2 & 3: thinning and widening of the midcentral part
  • Grades 4 & 5: Diffuse and advanced hair loss to the centro-parietal scalp

Complete balding is rare in women, as the frontal hairline is usually preserved even as the loss of hair progresses further back on the central scalp.

Differential Diagnosis

Diffuse alopecia areata (AA) is a nonscarring hair loss that begins as diffuse hair thinning, which evo-lves into hair loss of the anterior-temporal and parietal scalp.

Several other forms of hair loss occur in women that should be differentiated from FPHL:

Alopecia areata (AA) progresses more diffusely into the anterior-temporal and parietal scalp, and is indicative of thyroid disease.

Telogen effluvium (TE) is a temporary, stress-related form of hair loss that is often triggered by pregnancy, medications, surgery, and the presence of other medical conditions. In TE, hair may fall out in clumps in the shower, although in less severe cases it presents in the same manner as FPHL, with mid-central part widening.

Frontal fibrosing alopecia (FFA) is a rare inflammatory condition that presents as a regressing hairline that may be similar in appearance to FPHA, or as large bald spots. Hair loss is permanent and may occur on other areas of the face and body symptomatic of a systemic response to lichen planopilaris infection.

Medications such as antihypertensives, statins, antipsychotropics, and antiviral drugs may cause hair loss.

Medical disorders that produce symptoms of hair loss include cancer, iron deficiency, thyroid disorders, rheumatic disorders, and Treponema palladium infection. Hormonal dysfunction, particularly polycystic ovarian syndrome (PCOS) has been associated with FPHL as well as hirsuitism and other dermatologic disorders, possibly due to disrupted androgen levels.

Associated dermatologic conditions include vitiligo, atopic dermatitis, and psoriasis.

Treatments

Treatments for hair loss in women vary according to the initial cause, but are rather limited. For the most common forms of FPHL, minoxidil 2% solution is the first-line treatment. Applied topically, minoxidil is a potassium channel blocker that stimulates local blood flow to the hair follicles and extends the anagen phase of the hair-growth cycle.1-3 More recently, oral minoxidil combined with oral spironolactone is a therapy that has shown promising results.3 Oral finasteride, commonly prescribed for male pattern baldness, is not recommended for the treatment of alopecia in women.5

Corticosteroid injections, to the affected area may be effective for cases of alopecia areata. Injections will need to be repeated every month or two, with regrowth expected by 12 weeks.4

Microneedling devices, which have hundreds of tiny needles to penetrate the skin, have been shown in limited studies to promote new hair growth, particularly when used in conjunction with minoxidil.4

Low-level laser therapy is a treatment that has resulted in hair growth for hereditary forms of hair loss, alopecia areata, and hair loss from chemotherapy. It is also used following hair transplantation to stimulate new growth.4 Treatments are safe and painless, but need to be repeated weekly for months to be effective.

References

1. Bertoli MJ, Sadoughifar R, Schwartz RA, Lotti TM, Janniger CK. Female pattern hair loss: A comprehensive review. Dermatol Ther. 2020 Nov;33(6):e14055. doi:10.1111/dth.14055.

2. Ramos PM, Miot HA. Female Pattern Hair Loss: a clinical and pathophysiological review. An Bras Dermatol. 2015 Jul-Aug;90(4):529-43. doi:10.1590/abd1806-4841.20153370.

3. Chan L, Cook DK. Female pattern hair loss. Aust J Gen Pract. 2018 Jul;47(7):459-464. doi:10.31128/AJGP-02-18-4498.

4. American Academy of Dermatology – Hair Loss Resource Center. https://www.aad.org/public/diseases/hair-loss

5. Manabe M, Tsuboi R, Itami S, et al. Guidelines for the management of male and female pattern hair loss, 2017. Japanese Journal of Dermatology 127: 2763–2777, 2017.