Having discussed the anatomy and physiology of hair growth, let’s take on the issue that everyone cares about most – hair loss – something that affects nearly all men at some time in their lives, and a surprisingly large number of women. Because of the greater role hair plays in the public persona of women, they may suffer greater psychological impact although men and women both invest heavily in treatments to restore lost hair.
Most men eventually develop a receding M-shaped hairline and thinning hair on the top of the head – classic male pattern baldness, also referred to as androgenetic alopecia. It’s caused by the male hormone, dihydrotestosterone (DHT). DHT is five times as potent as testosterone and is vital for development of male genitalia in utero. It is also responsible for adult male body characteristics. Hair follicles in parts of the male scalp are particularly susceptible to the effects of DHT and miniaturize in response. DHT results from the action of the enzyme 5-alpha reductase on testosterone.
For men, the percentage experiencing hair loss tracks their age decade by decade. In their 20s approximately 20% of men experience noticeable hair loss. In their 30s, the number is 30% and so on. So in their 50s, half of men have noticeable hair loss. For women, the numbers are not as great but large nonetheless. Noticeable hair loss affects 40% of women by age 70. Each sex also has a particular pattern distribution of hair loss.
Although there is considerable crossover in pathophysiology with the effects of androgenic (male) hormones playing a major role in both sexes, the conditions are now referred to separately: MPHL (male pattern hair loss) and FPHL (female pattern hair loss.) Treatments for both are similar as is the morphological characteristics of the hair changes. It basically is a permanent return of terminal hair into vellus hair, those tiny, wispy, colorless, almost invisible hairs found on children’s bodies. The same thing happens in aging men and women. Hair follicles get smaller. The anagen stage of hair growth gets shorter, and the resting (telogen) stage gets longer. The result: Thin, very short hairs — and many follicles empty of hair shafts.
The good news is the follicle is still alive which makes it potentially possible for it to transition back into producing actively growing, longer, terminal hair.
TRIGGERS of FEMALE HAIR LOSS
Each day we lose about 50 to 100 hairs. When all is well an equal number is growing back. Severe stress (death in the family, divorce, job loss) and changes in diet (crash programs, lack of protein) can cause hair to shed more rapidly. Antidepressants, beta blockers, anti-acne prescriptions and medications with testosterone, which women may take to increase their sex drive, can cause hair loss. So can iron deficiency and an overactive or underactive thyroid gland. When women go through menopause and their estrogen levels fall, their hair often begins to thin. Many women also lose some hair a few months after giving birth because of the hormonal changes the body experiences.
OTHER LESS COMMON TYPES OF HAIR LOSS
Chemotherapy-induced alopecia is an expected and associated side-effect of chemotherapeutic agents used to treat malignancies. Because the target of these agents is rapidly growing tissue, i.e. where cells have high turnover rates, some normal cells are adversely affected, most notably cells in the gastrointestinal tract and hair follicles.
Alopecia areata is an autoimmune inflammatory condition which may affect the hair of the head, face, and body. Although most commonly thought of as an acquired disorder, congenital cases have been described. It has an incidence of 0.1–0.2%, and affects 1–2% of men and women. Hair involvement in AA is often patchy. Two variants of AA are alopecia totalis, a total loss of scalp hair, and alopecia universalis, total loss of scalp and body hair.
Alopecia mucinosa, often referred to as follicular mucinosis, is dermatologic condition where follicles accumulate a mucus-like material that causes an inflammatory condition that causes follicular death. The face, the neck, and the scalp are the most frequently affected sites, although lesions may appear on any part of the body.
Trichotillomania (also known as trichotillosis or hair pulling disorder) is an obsessive compulsive disorder characterized by the compulsive urge to pull out one’s hair, leading to hair loss and balding, distress, and social or functional impairment. It appears in the ICD chapter 5 on mental and behavioral disorders, and is often chronic and difficult to treat. Common areas for hair to be pulled out are the scalp, eyelashes, eyebrows, legs, arms, hands, nose and the pubic areas.
TREATMENTS for HAIR LOSS
Minoxidil (Rogaine) is used topically to treat hair loss in men and women. Products are a 2% lotion and 5% foam. Minoxidil was originally marketed as an effective oral anti-hypertensive drug that reduced blood pressure through vasodilatation. The observed side-effect of hair growth has been known for decades and related to the local increase in blood flow to hair follicles.
Finasteride (Propecia) is a Type II 5-alpha reductase inhibitor that prevents the conversion of testosterone into much more potent DHT. 5-alpha reductase is found predominantly in the prostate gland and in hair follicles. It has long been used to treat MPHL but studies show it is also effective in treating FPHL. Topical finasteride is available but without FDA approval. Side effects of oral finasteride in men include loss of libido, reduced ejaculate, and orgasmic inhibition. Pregnant women should not take finasteride.
Spironolactone (a type of potassium sparing diuretic) has androgen blocking properties and has been used with success in treating FPHL, particularly when combined with minoxidil.
Americans spend $800 million a year on hair restoration surgery. Great strides in hair transplant technology now make it possible to transplant hair in such a fashion that it is essentially undetectable. Early techniques often resulted in esthetically unpleasing results with tufts of hair placed into rows similar to the planting of crops. The effect was similar to how hair is placed into the heads of plastic dolls.
There are three advanced techniques in use now. The third actually increases the number of total follicles.
- Follicular Unit Hair Transplantation (FUT): Hair units are removed from a donor strip that has been excised from the donor area. This leaves a noticeable scar which can be visible if hair is not worn appropriately long.
- Follicular Unit Extraction (FUE): Individual hair units are removed directly from the donor area by a micro-punch individually, follicle by follicle, and transplanted to thinning areas. Now robotic machine use sophisticated software to identify and extract donor follicles.
- Hair Stem Cell Transplant (HST): Advanced surgical methods make it possible to transplant only part of a given follicle from which multiple hairs emerge. This enable part of the donor follicle, with its component stem cells, to remain in place making it possible for both the donor and transplanted parts of the same follicle to produce hair. The number of hair producing follicles increases because the donor follicle continues to function as a separate unit.
Low-level laser therapy (LLLT) is proved to stimulate hair re-growth. A review of randomized controlled trials (RCT) that investigated benefits of LLLT in patients with hair loss (male pattern hair loss (MPHL), female pattern hair loss (FPHL), alopecia areata (AA), and chemotherapy-induced alopecia (CIA)) demonstrated significant effect. 21 relevant studies were summarized in the review including 2 in vitro, 7 animal, and 12 clinical studies. The RCTs were critically appraised and found that FDA-cleared LLLT devices are both safe and effective in patients with MPHL and FPHL who did not respond or were not tolerant to standard treatments.
Low level laser therapy and hair regrowth: an evidence-based review. Lasers in Medical Science February 2016, Volume 31, Issue 2, pp 363-371
The growth of human scalp hair in females using visible red light laser and LED sources. Lasers in Surgery and Medicine;13 Aug 2014
Patients undergoing chemotherapy to treat malignancies almost always develop alopecia, which is usually universal and includes all hairy surfaces. In response, many patients resort to wearing wigs to replace lost hair. There is another choice.
Cooling caps worn during periods of relatively high blood levels of cytotoxic drugs can help. Designed to acutely lower the scalp temperature during drug administration, blood vessels constrict in response, thereby reducing exposure of the follicle to drugs that cause acute hair loss by inducing catagen.
Laboratory culture of follicular stem cells along with dermal papilla cell may one day lead to the ability to expand the number of follicles making it possible to create an unlimited number of transplantable hair follicles.
Researchers found that hair follicles in adult mice regenerate by re-awakening genes once active only in developing embryos. These findings provide unequivocal evidence that, like other animals such as newts and salamanders, mammals have the power to regenerate. These findings are published in the May 17 issue of Nature.
A gene called “sonic hedgehog” can convert resting hair into growing hair. It controls follicle size and growth.
Finding a method to upregulate this gene holds promise as a potential treatment. Sonic hedgehog is just one of several key genes scientists are tinkering with in labs.
Certain signaling molecules have direct influence on hair-follicle development. Prime examples are the “wnt” proteins. Wnt proteins can influence wound healing in a way that has less scarring and includes normal structures of the skin, such as hair follicles and oil glands. Researchers found that early wound healing in mice triggered an “embryonic-like” state in which dormant molecular pathways are awakened, sending stem cells to the area of injury. Unexpectedly, the regenerated hair follicles originated from non-hair-follicle stem cells.
By introducing more wnt proteins to the wound, the researchers found that they could take advantage of the embryonic genes to promote hair-follicle growth, thus making skin regenerate instead of just repair. Conversely by blocking wnt proteins, they also found that they could stop the production of hair follicles in healed skin.
Increased wnt signaling doubled the number of new hair follicles. This suggests that the embryonic window created by the wound-healing process can be used to manipulate hair-follicle regeneration, leading to novel ways to treat hair loss and hair overgrowth.
Cytokine and Growth Factor Manipulation
Platelet rich plasma (PRP) injections of the scalp have been shown to be of benefit in instigating hair re-growth. This is often performed in conjunction with microneedling, and may be part of transplant surgery protocols. PRP contains several cytokines and growth factors known to enhance hair growth.
Drjohn and Drgeorge, your humble BFT authors, are busy at work developing hair restoration products that incorporate cytokine and growth factor strategies. We have already learned to manipulated our beloved bone marrow mesenchymal stem cells to modulate their bio-signal outputs to accentuate wnt proteins. Our first product, a serum for use with dermal needling of the scalp is showing promising results. While we perform additional clinical studies on that formula, we are busy at work creating a complementary lotion for daily home use.
Photos of patient below provided by Dr. Diane Duncan of Fort Collins, Colorado. Patient received three dermal needling treatments of scalp, each a month apart, using hair serum developed by BFT authors. Device used provided by ProCell Therapies.