The most common type of hair loss in both men and women is Androgenetic Alopecia (AGA; other names: pattern alopecia, male pattern hair loss, male balding, female pattern hair loss, female androgenetic alopecia).
AGA is a genetically determined sensitivity of scalp hair follicles to androgens. The androgen dihydrotestoterone (DHT) binds to androgen-receptors on the hair follicle and signals them to undergo miniaturization. Terminal hairs (large, thick, dark-colored hair) gradually convert to vellus hairs (fine, thin, colorless hair) as their growth phase become shorter with each hair cycle.
The Hair Growth Cycle
Miniaturization of Hair Follicles
A definitive diagnosis is usually made just by a thorough scalp examination and history taking. AGA is gradual in onset with a characteristic distribution:
It is important to visit your dermatologist at least once to rule out other possible causes of hair loss (e.g. alopecia areata, trichotillomania, syphilis) or perhaps ensure that what you are encountering is simply a case of physiologic hair shedding (telogen effluvium; in other words, it’s totally normal!).
Did you know?
Androgenetic alopecia in men has been associated with several other medical conditions including coronary heart disease and enlargement of the prostate. Additionally, prostate cancer, disorders of insulin resistance (such as diabetes and obesity), and high blood pressure (hypertension) have been related to androgenetic alopecia. In women, this form of hair loss is associated with an increased risk of polycystic ovary syndrome (PCOS).
The only FDA-approved pharmacologic treatments for AGA are topical minoxidil 5% and/or finasteride 1mg/day for men and topical minoxidil 1% for women. Minoxidil and finasteride are considered first-line therapies because they have been extensively studied and show high tolerability albeit with a varied treatment response – some experience regrowth of hair that is cosmetically significant, while some only benefit from the slowing of additional hair loss. It is important to note that these drugs must be used continuously to maintain the results of treatment.
Minoxidil may be used twice a day on clean, dry, affected scalp areas. Usually some hair shedding occurs during the first two months of treatment as more hair follicles in the resting phase are pushed into the growth phase. Don’t panic. Hair regrowth is assessed at 4-8 months of therapy and stabilizes at 12 to 18 months. Side effects are uncommon but include contact dermatitis and overgrowth of hair on the face when used incorrectly.
Finasteride is taken at a dose of 1 mg per day with hair regrowth noted at 6 to 12 months of therapy and stabilizes at 2 years. Side effects occur in less than 2% of patients but include loss of libido and erectile/ejactulatory dysfunction. Prior to initation of this therapy, please visit your doctor so you may be guided accordingly.
A more permanent treatment for AGA is hair restoration surgery, which includes hair transplantation and/or scalp reduction surgery. Ideal candidates are those with stable or medically controlled AGA who have an adequate reservoir of donor hair follicles. These donor follicles are found at the back portion of your head and do not depend on androgen for their growth.
Emerging therapies (treatments currently with mixed reviews but may prove useful once larger-scale studies are done) are low level laser light therapy and platelet-rich plasma treatments.