Baldness

Alopecia

  

Hair loss in a 33-year-old man.

ICD-10L65.9ICD-9704.09DiseasesDB14765MedlinePlus003246MeSHD000505

Baldness, with some variance in definition, typically refers to the lack of hair on parts of or the whole scalp. It is generally considered a broader term than alopecia, which is loss of hair, since baldness can include context in which the loss is intentional.
The severity and nature of baldness can vary greatly as it ranges from male- and female-pattern alopecia (also called androgenetic alopecia or alopecia androgenetica); alopecia areata, which involves the loss of some of the hair from the head; alopecia totalis, which involves the loss of all head hair; and to the most extreme form, alopecia universalis, which involves the loss of all hair from the head and the body. Many cases of premature balding (in pre-middle aged individuals) are a result of "chronic stress-effect storage in the hypothalamus," a condition which causes scalp muscle bracing that can destroy the hair follicles.

Contents

1 Etymology

1.1 Discrepancy of definition


2 Background, cause, and incidence
3 Evolutionary theories of male pattern baldness
4 Psychological effects
5 Treatment

5.1 Finasteride and Minoxidil
5.2 Laser therapy
5.3 Surgery
5.4 Hair multiplication
5.5 Ketoconazole
5.6 Unsaturated fatty acids
5.7 Placebos
5.8 Exercise
5.9 Immunosuppressants
5.10 Saw palmetto
5.11 Beta sitosterol
5.12 Anti-androgens
5.13 WNT gene related


6 Concealing hair loss
7 Baldness folklore
8 Notes
9 References
10 Credits



Many scientists have contemplated whether or not balding is in all cases a preventable disease, or if it is commonly a natural occurrence, at least in males. Those who believe it to be natural phenomena—a belief determined mainly by its strong prevalence in men—have even speculated as to whether it serves a purpose. There are diverse treatments offered for the various forms of alopecia, with some showing limited success, but those who suffer baldness as a result of stress are able to regrow hair upon eliminating the stress effect before the hair follicles die.

Etymology
The term alopecia 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 likely 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.[1]

Discrepancy of definition
Some sources define balding as the loss of hair where it normally grows, including the head. However there are only two places where hair "normally" grows in both genders: the pubic area, and the area of the scalp. The lack of hair anywhere else on the body would not necessarily be considered abnormal and therefore is not usually categorized as baldness.

Background, cause, and incidence
The average human head has about 100,000 hair follicles. Each follicle can grow about 20 individual hairs in a person's lifetime. Average 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 that the prevalence of mid-frontal hair loss increases with age and affects 57 percent of women and 73.5 percent of men aged 80 and over.
Male-pattern baldness, androgenic alopecia, is characterized by hair receding from the lateral sides of the forehead, known as a "receding hairline." Receding hairlines are usually seen in males above the ages of 25. An additional bald patch may develop on the top (vertex). The trigger for this type of baldness is DHT, a powerful sex hormone, body and facial hair growth promoter that can adversely affect the hair on the head and prostate.[2]
The mechanism by which DHT accomplishes this is not yet fully 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. 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.
Traumas such as chemotherapy, childbirth, major surgery, poisoning, and severe stress may cause a hair loss condition known as telogen effluvium.[3]
Some mycotic infections can cause massive hair loss.[4]
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.). Tumors 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.
Evolutionary theories of male pattern baldness
 
There is no consensus regarding the origin of male pattern baldness. Most evolutionary 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 a superior 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 behaviors increase.[5] It is speculated that 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,[6] males and females viewed 6 male models with different levels of facial hair (beard and mustache 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.

Psychological effects
The psychological effects for individuals experiencing hair loss vary widely. Some people adapt to the change comfortably, while others have severe problems relating to anxiety, depression, social phobia, and in some cases, identity change.

 Retired bald NASA astronaut Story Musgrave.
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 (alexithymia) and may be more prone to avoiding family conflicts. Therapy can help families to cope with these psychological problems if they arise.[7] Psychological problems due to baldness, if present, are typically most severe at the onset of symptoms.[8]
Some men who experience balding may feel proud of their baldness, feeling a kindred relationship with famous or historically significant bald men. Baldness has, in recent years, in any case become less of a (supposed) liability due to an increasing fashionable prevalence of very short, or even completely shaven, hair among men, at least in western countries. This is even true for women, as shown by the case of some women singers who have a shaven head.

Treatment
Treatments for the various forms of alopecia have limited success, but those who suffer baldness as a result of stress are able to regrow hair upon eliminating the stress effect before the hair follicles die. Clinics specializing in the prevention of hair loss claim that the problem is now a very preventable, and even reversible, condition. Some hair loss sufferers make use of "clinically proven treatments" such as finasteride and topically applied minoxidil in an attempt to prevent further loss and regrow hair. As a general rule, it is easier to maintain remaining hair than it is to regrow; however, the treatments mentioned will supposedly help some of the users suffering from androgenetic alopecia, and there are new technologies in cosmetic transplant surgery and hair replacement systems that can be completely undetectable.

Finasteride and Minoxidil
The treatments for baldness approved by the United States Food and Drug Administration are finasteride (marketed for hair loss as Propecia) and minoxidil.
A pharmaceutical company reportedly sought to find the smallest effective quantity of finasteride and test its long-term effects on 1,553 men between ages 18 and 41 with mild to moderate thinning hair. Based on their research, 1 mg daily was selected, and after 2 years of daily treatment, over 83 percent of the 1,553 men experiencing male hair loss had actually maintained or increased their hair count from baseline.
Minoxidil was first used in tablet form as a medicine to treat high blood pressure, but it was noticed that some patients being treated with Minoxidil experienced excessive hair growth (hypertrichosis) as a side-effect. Further research showed that by applying topical Minoxidil solution directly to the scalp, it could prove to be beneficial to those experiencing hair loss.
FDA clinical trials showed that 65 percent of men with androgenetic alopecia maintained or increased their hair count from the use of minoxidil 5 percent in liquid form. 54 percent of these men experienced moderate to dense regrowth and 46 percent experienced hair loss stabilization and mild regrowth.
In controlled clinical studies of women aged 18-45, 2 out of 3 women with moderate degrees of hereditary hair loss reported re-growth after using 2 percent minoxidil. Initial results occur at 4 months with maximum results occurring at 8 months.

Laser therapy
A low level laser is shone directly on the scalp to stimulate hair growth through "Photo-Biostimulation" of the hair follicles. One product of these low level laser therapies is the "Hairmax Lasercomb." There is no peer-reviewed evidence to support this claim. The lasercomb was cleared by the FDA as being Substantially Equivalent (SE) to predicate devices legally marketed before May 28, 1978. This clearance is not the same as approval because it only applies to the lasercomb and not to any other similar laser based hair devices. The devices that the lasercomb proved itself equivalent to were a variety of FDA approved laser based/non hair growth devices intended for hair removal and pain relief, and 2 non FDA approved non laser based/hair growth devices such as the Raydo & Wonder Brush and the Vacuum Cap. These last two devices were sold in the early 1900's and are well established as medical quackery, but they were legal to market at the time which does satisfy the FDA's 510k SE criteria.

Surgery
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 sides of the head where hair is full and injected into bald or thinning areas.

Hair multiplication
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. 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.
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 re-implanting the cells into the scalp ([[Baldness treatments#Hair multiplication (Hair multiplication). The initial testing resulted in 70% of male patients regrowing hair.

Ketoconazole
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.

Unsaturated fatty acids
Particular unsaturated fatty acids such as gamma linolenic acid are 5 alpha reductase inhibitors if taken internally.[9]

Placebos
Interestingly, placebo treatments in studies often have reasonable success rates (although 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.[10]

Exercise
Regular aerobic exercise can help keep androgen levels (particularly free testosterone levels) naturally lower while maintaining overall health, lowering stress and increasing SHBG.[11][12]
Weight training without aerobic exercise may increase testosterone.[13][14]
One study suggests that both heavy exercise and increased fat intake, in combination, are required for increased free testosterone in strength trainers. Increased total or free testosterone would help them build and repair muscle, but may cause susceptible individuals to lose hair.[15]
However, there is at least one study that indicates a decline in free testosterone combined with an increase in strength due to an (unspecified) strength training regime.[16]

Immunosuppressants
Immunosuppressants applied to the scalp have been shown to temporarily reverse alopecia areata, though the side effects of some of these drugs make such therapy questionable.

Saw palmetto
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.[17]
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.[18][19][20]

Beta sitosterol
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.

Anti-androgens
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.

WNT gene related
In May 2007, US company Follica Inc, announced they have licensed technology from the University of Pennsylvania which can regenerate hair follicles by reawakening genes which were once active only in the embryo stage of human development.[21]

Concealing hair loss
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 (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.

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, and so forth. 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.[22] There is a 50 percent 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.[23] Another model for the inheritance of baldness is "autosomal dominant with mixed pentrance." That is, you can get it from either parent and it presents variably.
"Intellectual activity or psychological problems can cause baldness."
This notion may be due to the fact that cholesterol is involved in the process of neurogenesis and also the base material from which the body ultimately manufactures DHT. While the notion that bald men are more intelligent may lack credibility in the modern world, in the ancient world if a person was bald it was likely that he had an adequate amount of fat in his diet. Thus, his mental development was probably not stunted by malnutrition during his crucial formative years, he was more likely to be wealthy, and also have had access to a formal education. However, a sedentary lifestyle is less likely to correlate with intelligence in the modern world, and dietary fat content is not linked to economic class in modern developed countries. Of course, aside from all these scientific reasons, baldness could be linked to intellect or wisdom simply due to the fact that people go bald as they age and become more experienced.
Total testosterone exhibits a positive relation to tactual-spatial abilities and to the degree of lateralization. Total testosterone is negatively correlated with verbal fluency. Testosterone in the saliva is also significantly positively correlated to tactual-spatial test scores and, in addition, to field independence. DHT and the ratio DHT/total testosterone are positively related to verbal fluency and negatively to the degree of lateralization of tactual-spatial performance.[24]
"One's ethnicity can increase the chances of going bald."
This idea has been seen as somewhat discriminative and sensitive in nature, however studies have shown that men of Greek or Macedonian heritage have the highest percentage of bald or balding men. Studies done between six countries in Western Europe (Britain, France, Italy, Germany, Spain and Ireland) and four countries in Eastern Europe (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. 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)
"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.[25][26]
"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 does not 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.
"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."
While this may be a myth, 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 Pityrosporum ovale contamination in men with naturally oily scalps.
Notes


↑ D. Harper, "Bald," Online Etymology Dictionary. Retrieved April 29, 2017.

↑ A. Rebora, "Pathogenesis of androgenetic alopecia," J Am Acad Dermatol 50(2004, issue 5): 777-779. PMID 15097964.

↑ E. Nnoruka and N. Nnoruka, "Hair loss: Is there a relationship with hair care practices in Nigeria?" Int J Dermatol 44 (2005, Suppl 1): 13-17. PMID 16187950.

↑ P. Pappas, C. Kauffman, J. Perfect, P. Johnson, D. McKinsey, D. Bamberger, R. Hamill, P. Sharkey, S. Chapman, and J. Sobel, "Alopecia associated with fluconazole therapy," Ann Intern Med 123(1995, issue 5): 354-357. PMID 7625624.

↑ F. Muscarella and M. R. Cunningham, "The evolutionary significance and social perception of male pattern baldness and facial hair," Ethology and Sociobiology 17(1996, issue 2): 99-117.

↑ F. Muscarella and M. R. Cunningham, "The evolutionary significance and social perception of male pattern baldness and facial hair," Ethology and Sociobiology 17 (1996 issue 2): 99-117.

↑ F. Poot, "Psychological consequences of chronic hair diseases," Rev Med Brux 25(2004, issue 4): A286-288. PMID 15516058.

↑ J. Passchier, J. Erdman, F. Hammiche, and R. Erdman, "Androgenetic alopecia: stress of discovery," Psychol Rep 98(2006, issue 1): 226-228. PMID 16673981.

↑ T. Liang, and S. Liao, "Inhibition of steroid 5 alpha-reductase by specific aliphatic unsaturated fatty acids," Biochem J. 15(1992): 285. Retrieved April 29, 2017.

↑ J. Leyden, F. Dunlap, B. Miller, P. Winters, M. Lebwohl, D. Hecker, S. Kraus, H. Baldwin, A. Shalita, Z. Draelos, M. Markou, D. Thiboutot , M. Rapaport, S. Kang, T. Kelly, D. Pariser, G. Webster, M. Hordinsky, R. Rietschel, H. Katz, L. Terranella, S. Best, E. Round, and J. Waldstreicher, "Finasteride in the treatment of men with frontal male pattern hair loss," J Am Acad Dermatol 40(1999, issue 6 Pt 1): 930-937. PMID 10365924. 

↑ S. S. Tworoger, S. A. Missmer, A. H. Eliassen, et al., "Physical activity and inactivity in relation to sex hormone, prolactin, and insulin-like growth factor concentrations in premenopausal women: exercise and premenopausal hormones," Cancer Causes Control 18(2007, issue 7): 743-752. Retrieved April 29, 2017.

↑ A. Eliakim and D. Nemet, "Exercise and the male reproductive system," Harefuah 145(2006, issue 9): 677-681, 702. Retrieved April 29, 2017.

↑ C. Tsolakis, et al. "The influence of exercise on growth hormone and testosterone in prepubertal and early-pubertal boys," Hormones (Athens) 2(2003, issue 2): 103-112. Retrieved April 29, 2017. 

↑ J. P. Ahtiainen, A. Pakarinen, W. J. Kraemer, and K. Häkkinen, "Acute hormonal and neuromuscular responses and recovery to forced vs maximum repetitions multiple resistance exercises," Int J Sports Med. 24(2003, issue 6): 410-8. Retrieved April 29, 2017.

↑ J. Sallinen, A. Pakarinen, J. Ahtiainen, W. J. Kraemer, J. S. Volek, and K. Häkkinen, "Relationship between diet and serum anabolic hormone responses to heavy-resistance exercise in men," Int J Sports Med 25(2004, issue 8): 627-33. Retrieved April 29, 2017. 

↑ I. Ara, J. Perez-Gomez, G. Vicente-Rodriguez, J. Chavarren, C. Dorado, and J. A. L. Calbet, "Serum free testosterone, leptin and soluble leptin receptor changes in a 6-week strength-training programme," British Journal of Nutrition 96(2006, issue 6): 1053-1059. Retrieved April 29, 2017.

↑ F. Habib, M. Ross, C. Ho, V. Lyons, and K. Chapman, "Serenoa repens (Permixon) inhibits the 5alpha-reductase activity of human prostate cancer cell lines without interfering with PSA expression," Int J Cancer 114(2005, issue 2): 190-194. PMID 15543614.

↑ N. Prager, K. Bickett, N. French, and G. Marcovici, "A randomized, double-blind, placebo-controlled trial to determine the effectiveness of botanically derived inhibitors of 5-alpha-reductase in the treatment of androgenetic alopecia," J Altern Complement Med 8(2002, issue 2): 143-152. PMID 12006122.

↑ L. Marks, D. Hess, F. Dorey, M. Luz Macairan, P. Cruz Santos, and V. Tyler, "Tissue effects of saw palmetto and finasteride: use of biopsy cores for in situ quantification of prostatic androgens," Urology 57(2001, issue 5): 999-1005. PMID 11337315.

↑ C. Iehlé, S. Délos, et al., "Human prostatic steroid 5 alpha-reductase isoforms: a comparative study of selective inhibitors," J. Steroid Biochem Mol Biol" 54(1995 issue 5-6): 273-279. PMID 7577710.

↑ Introducing a new approach to hair loss. Follica, Inc. Retrieved April 29, 2017.

↑ A. Hillmer, S. Hanneken, S. Ritzmann, T. Becker, J. Freudenberg, F. Brockschmidt, et al., "Genetic variation in the human androgen receptor gene is the major determinant of common early-onset androgenetic alopecia," Am J Hum Genet 77(2005, issue 1): 140-148. PMID 15902657.

↑ W. Chumlea, T. Rhodes, C. Girman, et al., "Family history and risk of hair loss," Dermatology 209(2004 issue 1): 33-39. PMID 15237265.

↑ K. Christiansen, "Sex hormone-related variations of cognitive performance in !Kung San hunter-gatherers of Namibia," Neuropsychobiology 27(1993 issue 2): 97-107. PMID 8515835.

↑ B. Toone, M. Wheeler, M. Nanjee, P. Fenwick, and R. Grant, "Sex hormones, sexual activity and plasma anticonvulsant levels in male epileptics," J. Neurol Neurosurg Psychiatry 46(1983 issue 9): 824-826. PMID 6413659.

↑ J. Davidson, M. Kwanm, and W. Greenleaf, "Hormonal replacement and sexuality in men," Clin Endocrinol Metab 11(1982, issue 3): 599-623. PMID 6814798.



ReferencesISBN links support NWE through referral fees
Eddleston, M., and S. Pierini. Oxford Handbook of Tropical Medicine. New York, NY: Oxford University Press, 1999. ISBN 0192627724
Holley, L. Pate: The Facts of Nature Underlying Pate Thinning Hair and Baldness, Its Causes and a Professional Program for Prevention. Corvallis, OR: Pate Publishing, 1989. ISBN 0962508306
Muller, R. W. Baldness: Its Causes, Its Treatment and Its Prevention. reprint ed. Whitefish, MT: Kessinger Publishing, 2007. ISBN 9780548356241

Credits
New World Encyclopedia writers and editors rewrote and completed the Wikipedia article
in accordance with New World Encyclopedia standards. This article abides by terms of the Creative Commons CC-by-sa 3.0 License (CC-by-sa), which may be used and disseminated with proper attribution. Credit is due under the terms of this license that can reference both the New World Encyclopedia contributors and the selfless volunteer contributors of the Wikimedia Foundation. To cite this article click here for a list of acceptable citing formats.The history of earlier contributions by wikipedians is accessible to researchers here:

Baldness  history
Alopecia  history
The history of this article since it was imported to New World Encyclopedia:

History of "Baldness"
Note: Some restrictions may apply to use of individual images which are separately licensed.