Baldness is a trait which involves the state of lacking hair where it often grows, especially on the head. The most common form of baldness is a progressive hair thinning condition called androgenic alopecia or 'male pattern baldness' that occurs in adult human males and some primate species. The severity and nature of baldness can vary greatly; it ranges from male and female pattern alopecia (androgenetic alopecia, also called androgenic alopecia or alopecia androgenetica), alopecia areata, which involves the loss of some of the hair from the head, and alopecia totalis, which involves the loss of all head hair, to the most extreme form, alopecia universalis, which involves the loss of all hair from the head and the body. Treatment for alopecia has limited success. The more hair lost, the less successful the treatment will be.

Background, cause and incidence

The most noticeable part of human hair is the hair on the head, more prominent in some than others, which is more dense than most hair found elsewhere on the body. The average human head has about 100,000 hair follicles. Each follicle can grow about 20 individual hairs in a person's lifetime. Average normal hair loss is about 100 strands a day.

Incidence of pattern baldness varies from population to population based on genetic background. Environmental factors do not seem to affect this type of baldness greatly. One large scale study in Maryborough, in central Victoria (Australia) showed the prevalence of mid-frontal hair loss increases with age and affects 57% of women and 73.5% of men aged 80 and over.

Male pattern baldness is characterized by hair receding from the lateral sides of the forehead, known as "receding hairline" or "receding brow." An additional bald patch may develop on top (vertex). The trigger for this type of baldness (called androgenetic alopecia) is DHT, a powerful sex hormone that adversely affects the hair and prostate.

The mechanism by which DHT accomplishes this is not yet understood. In genetically-prone scalps, DHT initiates a process of follicular miniaturization. Through the process of follicular miniaturization, hair shaft width is progressively decreased until scalp hair resembles fragile vellus hair or "peach fuzz" or else becomes non-existent. Onset of hair loss sometimes begins as early as end of puberty, and is mostly genetically determined. Male pattern baldness is classified on the Hamilton-Norwood scale I-VIII.

It was previously believed that baldness was inherited from a person's maternal grandfather. While there is some basis for this belief, both parents contribute to their offspring's likelihood of hair loss. Most likely, inheritance is technically "autosomal dominant with mixed penetrance" (see 'baldness folklore' below)

There are several other kinds of baldness:

• Traction alopecia is most commonly found in people with ponytails or cornrows who pull on their hair with excessive force. Wearing a hat shouldn't generally cause this, though it is a good idea to let your scalp breathe for 7 hours a day .
• Traumas such as chemotherapy, childbirth, major surgery, poisoning, and severe stress may cause a hair loss condition known as telogen effluvium.
• Some mycotic infections can cause massive hair loss.
• Alopecia areata is an autoimmune disorder also known as "spot baldness" that can result in hair loss ranging from just one location (Alopecia areata monolocularis) to every hair on the entire body (Alopecia areata universalis).
• Localized or diffuse hair loss may also occur in cicatricial alopecia (lupus erythematosus, lichen plano pilaris, folliculitis decalvans, central centrifugal cicatricial alopecia, postmenopausal frontal fibrosing alopecia, etc.). Tumours and skin outgrowths also induce localized baldness (sebaceous nevus, basal cell carcinoma, squamous cell carcinoma).
• Hypothyroidism can cause hair loss, especially thinning of the outer third of the eyebrows
• Temporary loss of hair can occur in areas where sebaceous cysts are present for considerable duration; normally one to several weeks in length.

Etymology

The term alopecia (al-oh-PEE-she-uh) is formed from the Greek αλώπηξ (alopex), meaning fox. The origin of this usage is because this animal sheds its coat twice a year.

The term bald derives from the English word balde, which means "white, pale", or Celtic ball, which means "white patch or blaze", such as on a horse's head.

Evolutionary theories of male pattern baldness

There is no consensus regarding the details of the evolution of male pattern baldness. Most theories regard it as resulting from sexual selection. A number of other primate species also experience hair loss following puberty, and some primate species clearly use an enlarged forehead, created both anatomically and through strategies such as frontal balding, to convey increased status and maturity. The assertion that MPB is intended to convey a social message is supported by the fact that the distribution of androgen receptors in the scalp differs between men and women, and older women or women with high androgen levels often exhibit diffuse thinning of hair as opposed to male pattern baldness.

One theory, advanced by Muscarella and Cunningham, suggests baldness evolved in males through sexual selection as an enhanced signal of aging and social maturity, whereby aggression and risk-taking decrease and nurturing behaviours increase.(1) This may have conveyed a male with enhanced social status but reduced physical threat, which could enhance ability to secure reproductive partners and raise offspring to adulthood.

In a study by Muscarella and Cunnhingham, males and females viewed 6 male models with different levels of facial hair (beard and moustache or clean) and cranial hair (full head of hair, receding and bald). Participants rated each combination on 32 adjectives related to social perceptions. Males with facial hair and those with bald or receding hair were rated as being older than those who were clean-shaven or had a full head of hair. Beards and a full head of hair were seen as being more aggressive and less socially mature, and baldness was associated with more social maturity.

Approaches to baldness

Psychological implications

The psychological implications for individuals experiencing hair loss vary widely. Some people adapt to the change very well, others have severe problems relating to anxiety, depression, social phobia, and in some cases, problems with identity change.

Alopecia induced by cancer chemotherapy has been reported to cause changes in self-concept and body image. Body image does not return to the previous state after regrowth of hair for a majority of patients. In such cases, patients have difficulties expressing their feelings (what is called alexithymia) and may be more prone to avoiding family conflicts. Family therapy can help families to cope with these psychological problems if they arise.

Psychological problems due to baldness, if present, are typically most severe at the onset of symptoms.

Some balding men may feel proud of their baldness, feeling a kindred relationship with famous charismatic bald film actors such as Yul Brynner, Vin Diesel, Michael Chiklis, Telly Savalas, Ben Kingsley, Patrick Stewart or Bruce Willis; or politicians such as Ed Koch and James Carville; or sportsmen such as wrestler Stone Cold Steve Austin, footballer Zinedine Zidane or tennis star Andre Agassi. Much of these celebrities' perceived masculinity and handsomeness derives from their most obvious distinguishing feature. This is not yet true for women, as there are few female celebrities who are bald by choice, chemotherapy or genetics/environment.

Many companies have built a successful business selling products that reverse baldness, by allegedly regrowing hair, transplanting hair or selling hairpieces. There is very little evidence that any of those which claim hair regrowth actually work.

Preventing and reversing hair loss

It is easier to prevent the falling out of healthy hairs than to regrow hair in follicles that are already dormant. Finasteride (marketed in the U.S. as Propecia) and minoxidil (marketed in the U.S. as Rogaine, and some places as Regaine) have shown some success in partially reversing loss. In a one-year study of finasteride, evaluation after one year showed five of 21 subjects (23.8%) had two-grade improvement in MNHS grade on a modified Norwood/Hamilton scale and 12 of 21 subjects (57.1%) had one-grade improvement; the others remained at the same grade. However such treatments are generally ineffective at treating extreme cases of hair loss.

Surgery is another method of reversing hair loss and baldness, although it may be considered an extreme measure. The surgical methods used include hair transplantation, whereby hair-producing follicles are taken from the back and sides of the head and injected into bald or thinning areas.

Looking forward, the prospective treatment of hair multiplication/hair cloning, which extracts self-replenishing follicle stem cells, multiplies them many times over in the lab, and microinjects them into the scalp, has been shown to work in mice, and is currently under development, expected by some scientists to be available to the public in 2009–2015. Subsequent versions of the treatment are expected by some scientists to be able to cause these follicle stem cells to simply signal the surrounding hair follicles to rejuvenate. See Baldness treatments

Topical application of ketoconazole, which is both an anti-fungal and a potent 5-alpha reductase inhibitor, is often used as a supplement to other approaches.

Interestingly, placebo treatments in studies often have reasonable success rates, though not as high as the products being tested, and even similar side-effects as the products. For example, in Finasteride (Propecia) studies, the percent of patients with any drug-related sexual adverse experience was 3.8% compared with 2.0% in the placebo group.

Regular aerobic exercise can help keep androgen levels (particuarly free androgen levels) naturally lower while maintaining overall health, lowering stress and increasing SHBG. It has been suggested that strinct weight training may have a detrimental effect on hair in studies where aerobic exercise (only) was compared to either weight training (only) or a moderately sedentary life. [ ]; However, there is at least one study that indicates a decline in free testosterone combined with an increase in strength. The possibility that the training was also aerobic cannot be ruled out.

Stress reduction can be helpful in slowing hair loss. Immunosuppressants applied to the scalp have been shown to temporarily reverse hair loss, though the possibly lethal side effects of this treatment make it untenable. Saw Palmetto (Serenoa repens) is an herbal DHT inhibitor often claimed to be cheaper and have fewer side effects than finasteride and dutasteride. Unlike other 5alpha-reductase inhibitors, Serenoa repens induces its effects without interfering with the cellular capacity to secrete PSA. Saw palmetto extract has been demonstrated to inhibit both isoforms of 5-alpha-reductase unlike finasteride which only inhibits the (predominant) type 2 isoenzyme of 5-alpha-reductase.

Polygonum Multiflorum is a traditional Chinese cure for hair loss. Whether the plant itself is useful, the general safety and quality control of herbs imported from China can be questionable.

Beta Sitosterol, which is a constituent in many seed oils, can help to treat BHP by lowering cholesterol. If used for this purpose, an extract is best. Consuming large amounts of oil to get at small quantities of beta sitosterol is likely to exacerbate male pattern baldness.

Resveratrol, from grape skins, is a lipase inhibitor. By decreasing the body's ability to absorb fat through the intestine walls, it reduces the total fat and calorie content of a person's diet.

While drastic, broad spectrum anti-androgens such as flutamide are sometimes used topically. Flutamide is potent enough to have a feminizing effect in men, including growth of the breasts.

In March 2006, Curis announced that it had received the first preclinical milestone, a $1,000,000 cash payment, in its hair growth program with Procter & Gamble Pharmaceuticals, a division of The Procter & Gamble Company. The program is focused on the potential development of a topical Hedgehog agonist for hair growth disorders, such as male pattern baldness and female hair loss.

In October 2006, UK biotechnology firm Intercytex announced they have successfully tested a method of removing hair follicles from the back of the neck, multiplying them and then reimplanting the cells into the scalp (Hair multiplication). The initial testing resulted in 70% of male patients regrowing hair. This treatment method is expected to be available to the public by 2009 .

In January 2007, Italian stem-cell researchers say they've come up with a new technique for curing baldness. Pierluigi Santi of a Genoa clinic said stem cells could be used to "multiply" hair roots. He said the clinic would be ready to perform its first hair transplants on priority patients - those who have lost their hair in fires or other accidents - within a few months. After that, he said, "we'll open our doors to paying customers". Santi's approach works by splitting roots and growing new follicles.

Concealing hair loss

Head

One method of hiding hair loss is the "comb over", which involves restyling the remaining hair to cover the balding area. It is usually a temporary solution, useful only while the area of hair loss is small. As the hair loss increases, a comb over becomes less effective. When this reaches a stage of extreme effort with little effect — it can make the person the object of teasing or scorn.

Another method is to wear a hat or a hairpiece — a wig or toupee. The wig is a layer of artificial or natural hair made to resemble a typical hair style. In most cases the hair is artificial. Wigs vary widely in quality and cost. In the United States, the best wigs — those that look like real hair — cost up to tens of thousands of dollars. Organizations such as Wigs for Kids and Locks of Love collect individuals' donations of their own natural hair to be made into wigs for young cancer patients who have lost their hair due to chemotherapy or other cancer treatment in addition to any type of hair loss.

Eyebrows

Though not as common as the loss of hair on the head, chemotherapy, hormone imbalance, forms of alopecia, and other factors can also cause loss of hair in the eyebrows. Artificial eyebrows are available to replace missing eyebrows or to cover patchy eyebrows.

Embracing baldness

Of course, instead of concealing hair loss, one may embrace it. A shaved head will grow stubble in the same manner and at the same rate as a shaved face. Many celebrities and athletes shave their heads. They spread the message of baldness by shaving the heads of adults to raise money for curing childhood cancer, which often causes children to lose their hair (see Head shaving). Female baldness is less socially accepted. Sharon Blynn, Bald Is Beautiful founder and an ovarian cancer survivor whose motto is "Always smile from the inside out!" encourages women to define beauty for themselves on their own terms.

Baldness folklore

There are many myths regarding the possible causes of baldness and its relationship with one's virility, intelligence, ethnicity, job, social class, wealth etc. While skepticism is warranted due to lack of scientific validation, some of these myths may have a degree of underlying truth.

• "You inherit baldness from your mother's father."

  Previously, early baldness of the androgenic type was thought to be sex linked dominant in males and to be sex linked recessive in females.

  Research suggests that the gene for the androgen receptor, which is significant in determining probability for hair loss, is located on the X chromosome and so is always inherited from the mother's side. There is a 50% chance that a person shares the same X chromosome as their maternal grandfather. Because women have two X chromosomes, they will have two copies of the androgen receptor gene while men only have one.

  However research has also shown that a person with a balding father also has a significantly greater chance of experiencing hair loss.

This idea has been seen as somewhat descriminative and sensitive in nature, however studies have shown that men of Greek or Macedonian heritage have the highest percentage of bald or balding men.(age goup 16-28, typical, non married, non-drug using, males) Studies done between 6 countries in Western Europe, incl. Britain, France, Italy, Germany, Spain and Ireland and 4 countries in Eastern Europe including Greece, Macedonia, Bulgaria and Romania show that Greek men of the same age group and study period had the highest percentage of full crown baldness or Alopeciae totalis (front, top and back) Another typical study during the same period showed that Greek men, 1700 out of 2457 total studied males also suffered the highest amount of random alopecia areata among men (aged 16-28, typical, non-drug using males)

• "Baldness can be caused by emotional stress, sexual frustration etc."

  Emotional stress has been shown to accelerate baldness in genetically susceptible individuals.

  Stress due to sleep deprivation in military recruits lowered testosterone levels, but is not noted to have effected SHBG.

  Thus, stress due to sleep deprivation in fit males is unlikely to elevate DHT. Whether it can cause hair loss by some other mechanism is not clear.

• "Bald men are more 'virile' or sexually active than others."

  Levels of free testosterone are strongly linked to libido and also DHT levels, but unless free testosterone is virtually non-existent levels have not been shown to affect virility. Men with androgenic alopecia are more likely to have a higher baseline of free androgens. However sexual activity is multifactoral, and androgenic profile is also not the only determining factor in baldness. Additionally, because hair loss is progressive and free testosterone declines with age, a person's hairline may be more indicative of their past than present disposition.

• "Shaving hair makes it grow back stronger"

  Proposed as a popular remedy against baldness, it is very probably just an illusion similar to the one perceived after shaving one's beard or mustache. Shaving one's head doesn't increase the number of healthy hair present on the scalp, and, after the remaining hair has grown a few millimeters, no enhancement in thickness or overall quality can be observed.

• "Frequent ejaculation causes baldness"

  There are many misconceptions about what can help prevent hairloss, one of these being that frequent ejaculation may have an influence on MPB. While ejaculation significantly lowers levels of relaxin (a 5-alpha reductase inhibitor) in a male's body and causes testosterone levels to temporarily elevate , the claim that frequent ejaculations can cause baldness is often viewed with skepticism. Higher free testosterone levels may correlate with both hairloss and increased sex drive in predisposed individuals.

• "Standing on one's head alleviates baldness"

  The "blood-flow" theory, which led men to stand on their heads in the 1980s, can be found in the advertising for many of the fake hairloss treatments for sale on the internet. While Minoxidil is a vasodilator and is speculated to work, in part, by increasing blood flow to hair follicles, there is no evidence that standing on one's head can alleviate baldness.

• "Tight hats cause baldness."

  This one probably started in the military where young men entering the service were required to wear hats and soon showed signs of going bald, or at least of hair thinning. This is due to coincidental timing. The age that young men enter the military is also the same age that male pattern hair loss begins. This is due to dihydrotestosterone, not hats. Hats do cause hair breakage and, to a lesser degree, split ends. Since hats are not washed as frequently as other clothing, they can also lead to scalp uncleanliness and possible P. ovale contamination in men with naturally oily scalps.
  

Trivia

• John D. Rockefeller had an extreme case of alopecia that caused him to lose all of the hair on his face, including his eyebrows and eyelashes. Another famous person who suffers from similarly severe alopecia is Italian football referee Pierluigi Collina. Actor Patrick Stewart lost most of his hair to male-pattern baldness by age 19 (His natural "horse-shoe" of remaining hair can be seen in the film L.A. Story, along with his numerous appearances as Captain Jean-Luc Picard in Star Trek).
• Eunuchs rarely go bald, due to to reduced hormone levels.
• Baldness is not only a human trait. Some other primates, such as chimpanzees, stump-tailed macaques, and South American nakari show progressive thinning of the hair on the scalp after adolescence. Adult stump-tailed macaques, in fact, are commonly used in laboratories for the testing of hair-regrowth treatments.
• The different predecessors of Old World and New World vultures convergently evolved a bald head, preventing feathers from retaining material from the vulture's diet of rotting meat, as well as helping in heat regulation.
• The American Bald Eagle is not really bald. The feathers on the head of this bird are white, in contrast to the brown feathers of the body. The term "bald" derives from the English word balde, which means "white".
• Little Britain actor and creator Matt Lucas has suffered from Alopecia Universalis since the age of 6 and has since utilised his situation in the creation of popular characters from Little Britain, such as Andy.