AGA in women has been termed ‘female pattern hair loss’ because the androgen dependence of hair loss in all women with patterned alopecia, has not been sufficiently demonstrated. Hair loss in women can be absolutely devastating for the sufferer’s self image and emotional well being.
Onset – True prevalence of female pattern hair loss is difficult to determine given that most authors either have not clearly stated the diagnostic criteria used or have chosen to focus on only one pattern of FPHL.
There are notable differences in the age at onset of pattern hair loss in men and women. In women, there are 2 main peaks of onset of pattern hair loss: the third decade and the second peak is from the age of about 40 through menopause. Those with an earlier age of onset have more severe hair loss.
The degree of hair loss and clinical presentation of AGA in women differ from men. Women may present with either an episodic or continuous increase in hair shedding without any noticeable reduction in hair volume or diffuse thinning over the crown with loss of hair volume with no history of hair shedding. Women with AGA-related increased hair shedding often present prior to the development of reduction in hair volume over the crown.
Majority of women are diagnosed as FPHL by thinning over the midline part with preservation of frontal hair margin, the pattern of loss that is only apparent when one performs a midline part.
The “Christmas tree” pattern of hair loss i.e increasing hair loss towards the front of the scalp is another useful clinical clue to diagnose androgenetic alopecia in women.
However a majority of women do not present with the above clinical features and may go undiagnosed. In a subset of women, hair loss occurs over the parietal, temporal and occipital scalp with or without vertex thinning, thus posing a diagnostic challenge to the clinician (personal observation).
The various patterns of presentation that has been observed in women with FPHL, is enlisted below-
- Diffuse central thinning with preservation of frontal margin.
- Frontal accentuation ( Christmas tree) i.e. breach in frontal line
- Diffuse thinning of hair over entire scalp, often more noticeable thinning towards the back of the scalp.
- Diffuse thinning of hair over the parietal region.
- Male pattern- (Fronto-Parietal)
- Bitemporal thinning is commonly associated with, but not necessarily indicative of female pattern hair loss.
- There is no any recession of the frontal hairline although the hair on the frontal margin are miniaturized i.e. finer and shorter
In females who presented with AGA, polycystic ovaries were observed in 28%–67%, hirsutism in 21%, and acne in 43%.
Grading scale for FPHL
Sinclair Scale (Yip and Sinclair 2006)
Grade 1: This is normal. This pattern is found in all girls prior to puberty but in only forty-five percent of women aged eighty or over.
Grade 2: Shows a widening of the central part.
Grade 3: Shows a widening of the central part and thinning of the hair on either side of the central part.
Grade 4: Reveals the emergence of a diffuse hair loss over the top of the scalp.
Grade 5: Indicates advanced hair loss.
Diagnosis of FPHL is mainly by clinical and trichoscopic examination. In difficult cases histopathological evaluation is necessary. Along with the scalp hair assessment, clinical examination for features of androgenism should be undertaken. Women with menstrual cycle disturbances or those exhibiting marked acne, hirsutism, or both, should be investigated fully.
Woman with mid scalp widening are straightforward case of FPHL. When women present with increased hair shedding, but little or no reduction in hair volume over the mid-frontal scalp, various differential diagnoses should be considered, in particular acute and chronic telogen effluvium and diffuse alopecia areata. Other causes for diffuse hair shedding in women are included in the Table.
Causes of diffuse hair shedding in women
- Drug-induced Hair Loss
- Telogen Effluvium
- Telogen Gravidarum
- Chronic Telogen Effluvium (CTE)
- Early Androgenetic Alopecia
- Diffuse Alopecia Areata
- Scarring Alopecia
- Iron Deficiency
- Starvation/Malabsorption/Crash Diet
- Hypothyroidism and Hyperthyroidism
- Chronic Renal Failure and Hepatic Failure
- Acute Lupus Erythematosus
- Advanced Malignancy
Minoxidil Topical – Minoxidil has been shown to arrest hair loss or to induce mild to moderate hair regrowth in approximately 60% of women with FPHL. A clinical trial comparing 5% and 2% formulations of minoxidil found a mean increase in non-vellus hair counts after 48 weeks of 18% and 14%, respectively.
According to the package insert, minoxidil may be harmful if used when pregnant or breastfeeding. It is pregnancy category C. Although a 1-year, prospective study showed no increase in the cardiovascular events or adverse pregnancy outcomes among patients on topical minoxidil versus controls.
Oral antiandrogen therapy with cyproterone acetate, spironolactone or flutamide is widely used in the treatment of FPHL. Flutamide can improve hair growth after only 6 months of treatment, and offers long-term stability in FPHL.
Finasteride has not shown the same efficacy in FPHL as seen in male AGA. In postmenopausal women, a 1-year course of finasteride 1 mg daily failed to improve hair loss over placebo. In normoandrogenic women, it seems to be efficacious when used in higher doses (5 mg).
There are published reports of effectiveness of micro-needling of the scalp, autologous platelet rich plasma and low level laser therapy for pattern hair loss.