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Classification and external resources

Alopecia in a 33-year-old man.
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Classification and external resources

Alopecia in a 33-year-old man.

Alopecia (pron.: /ˌæləˈpʃə/, from Classical Greek ἀλώπηξ, alōpēx) means loss of hair from the head or body. Alopecia can mean baldness, a term generally reserved for pattern alopecia or androgenic alopecia. Compulsive pulling of hair (trichotillomania) can also induce hair loss. Hairstyling routines such as tight ponytails or braids may cause traction alopecia. Both hair relaxer solutions, and hot hair irons can also induce hair loss. In some cases, alopecia is due to underlying medical conditions, such as iron deficiency.[1]

Generally, hair loss in patches signifies alopecia areata. Alopecia areata typically presents with sudden hair loss causing patches to appear on the scalp or other areas of the body. If left untreated, or if the disease does not respond to treatment, complete baldness can result in the affected area, which is referred to as alopecia totalis. When the entire body suffers from complete hair loss, it is referred to as alopecia universalis. It is similar to the effects that occur with chemotherapy.[2]


Signs and symptoms

Symptoms of alopecia include hair loss, skin lesions, and scarring. In male-pattern hair loss, loss and thinning begin at the temples and the crown and either thins out or falls out. Female-pattern hair loss occurs at the frontal and parietal.


Causes of alopecia include:


Hair follicle growth occurs in cycles. Each cycle consists of a long growing phase (anagen), a short transitional phase (catagen) and a short resting phase (telogen). At the end of the resting phase, the hair falls out (exogen) and a new hair starts growing in the follicle beginning the cycle again.

Normally, about 40 (0-78 in men) hairs reach the end of their resting phase each day and fall out.[8] When more than 100 hairs fall out per day, clinical hair loss (telogen effluvium) may occur[citation needed]. A disruption of the growing phase causes abnormal loss of anagen hairs (anagen effluvium).


Because they are not usually associated with an increased loss rate, male-pattern and female-pattern hair loss do not generally require testing. If hair loss occurs in a young man with no family history, drug use could be the cause.


  • In hair transplants, a dermatologist or cosmetic surgeon takes tiny plugs of skin, each which contains a few hairs, and implants the plugs into bald sections. The plugs are generally taken from the back or sides of the scalp. Several transplant sessions may be necessary.
  • Scalp reduction is the process is the decreasing of the area of bald skin on the head. In time, the skin on the head becomes flexible and stretched enough that some of it can be surgically removed. After the hairless scalp is removed, the space is closed with hair-covered scalp. Scalp reduction is generally done in combination with hair transplantation to provide a natural-looking hairline, especially those with extensive hair loss.


In May 2009, researchers in Japan identified a gene, SOX21, that appears to be responsible for hair loss in humans[15] and a researcher in India found a link between androgenic hormone and hair loss. Androgenic alopecia is a counterproductive outcome of the anabolic effect of androgens.[16]

In March 2012, George Cotsarelis discovered a causal link between elevated levels of prostagladin D2 (PDG2) and androgenic alopecia. Abnormally high levels of PDG2 (a nearly three-fold increase) were discovered in tissue samples of balding areas compared to haired areas of the scalp. During the course of the research, a PDG2-binding receptor, GPR44, was also discovered. Compounds aimed at targeting the GPR44 receptor are currently being researched.[17]

See also


  1. ^ "Hair loss, balding, hair shedding. DermNet NZ". Archived from the original on 14 November 2007. Retrieved 2007-12-07.
  2. ^ "Chemotherapy and hair loss: What to expect during treatment -". Archived from the original on 26 November 2007. Retrieved 2007-12-07.
  3. ^ "What is Alopecia: What Causes Alopecia?". MedicalBug. 6 February 2012. Retrieved 28 March 2012.
  4. ^ "Many causes of hair loss".
  5. ^ Alopecia Areata, by Maria G. Essig, MS, ELS, Yahoo! Health
  6. ^ "Alopecia: Causes". Better Medicine. Retrieved 28 March 2012.
  7. ^ "Infectious hair disease – syphilis". Retrieved 2011-11-17.
  8. ^ Carina A. Wasko; Christine L. Mackley; Leonard C. Sperling; Dave Mauger; Jeffrey J. Miller. Standardizing the 60-Second Hair Count. Arch Dermatol., 2008;144(6):759-762 [link]
  9. ^ "The hair pull test". Retrieved 28 March 2012.
  10. ^ Rudnicka L, Olszewska M, Rakowska A, Kowalska-Oledzka E, Slowinska M. (2008). "Trichoscopy: a new method for diagnosing hair loss". J Drugs Dermatol 7 (7): 651–654. PMID 18664157.
  11. ^ H. Panda: Handbook On Ayurvedic Medicines With Formulae, Processes And Their Uses [1]
  12. ^ S. Suresh Babu: Homemade Herbal Cosmetics
  13. ^ Zhong Ying Zhou, Hui De Jin: Clinical manual of Chinese herbal medicine and acupuncture [2]
  14. ^ Ablon, Glynis (2012). "A Double-blind, Placebo-controlled Study Evaluating the Efficacy of an Oral Supplement in Women with Self-perceived Thinning Hair". Journal of Clinical and Aesthetic Dermatology 5 (11): 28–33. PMC 3509882. //
  15. ^ Scientists identify gene that may explain hair loss Reporting by Tan Ee Lyn; Editing by Alex Richardson, May 25, 2009, Reuters
  16. ^ Soni VK (September 2009). "Androgenic alopecia: a counterproductive outcome of the anabolic effect of androgens". Med. Hypotheses 73 (3): 420–6. doi:10.1016/j.mehy.2009.03.032. PMID 19477078.
  17. ^ "Scientists identify protein responsible for male pattern baldness". Fox News. 21 March 2012. Retrieved 21 May 2012.

External links