what are the types of alopecia?
Alopecia is loss of hair from the head and body. Alopecia can be broadly grouped into familial (genetic) type or acquired type.
Androgenetic Alopecia and its subgroups come under genetic types. The androgenetic hair loss tend to run in families. Alopecia areata, an autoimmune disorder, appear to have genetic predisposition in some cases.
Acquired baldness encompasses all other types of hair loss. Acquired alopecia is further categorized with respect to the causative factors and the extent of affliction. The triggering factors include certain medical conditions, diseases, febrile illness, psychological disorders, chemicals, cancer chemotherapy, parturition and habits. Certain types of alopecia disappear on their own whereas some types have no cure. Identifying the type of hair loss is essential for an effective treatment.
Androgenetic Alopecia
Androgenetic alopecia is a common type of androgen induced hair loss disorder affecting genetically predisposed men and women. The genetic predisposition and the presence of increased androgen gradually convert terminal hair into short, fine, light-colored, and barely noticeable
vellus hair. Androgenic hormones have different effect on follicles at different areas of the body.
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Androgens stimulate growth of terminal hair on the face, armpits and pubic area on reaching puberty. The same type of androgens lead to catagenic miniaturization and dormancy of follicles on the scalp and temples. Early androgenic alopecia is associated with insulin resistance and metabolic syndrome.
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Male pattern hair loss
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Androgenic loss of hair in men begins above the temples, frontal hairline and vertex. With advancing age a rim of hair at the sides and rear of the head remains. In some rare cases it can progress into total loss of hair. Though loss of hair may cause psychological stress due to its effect on appearance, men are able to cope and retain integrity of personality. In Hamilton–Norwood scale of classification of hair loss in men, the progression is graded from type I to VII. Dr. James Hamilton introduced the measurement scale in 1951 and it was later revised and updated by Dr O'Tar Norwood in the 1975. Hamilton-Norwood scale is frequently used for clinically assessing the severity of androgenetic alopecia in men.
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Female pattern hair loss
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Female pattern hair loss is becoming more common and the prevalence increases with advancing age. In female pattern there is thinning of hair all over the head. However unlike the male pattern, the frontal hairline does not recede. Further, in female pattern very rarely there is total loss of hair. Female pattern is considered androgenetic type if there is androgen increase. Affected women suffer psychological distress and their social life is impaired. In Ludwig's classification of hair loss in women, the progression is graded as minimal (type I), moderate (type II), and severe (type III).
Alopecia areata typically appears as small round patches of hair loss with underlying smooth unscarred skin. It is a non contagious disorder believed to be caused by autoimmunity. The body's immune system attacks its own anagen hair follicles, suppressing or stopping hair growth in the affected area of skin. This type of loss of hair can appear on scalp, beard or any other hair bearing part of the body. In many cases the hair grows back after a few months or years. In some rare cases hair loss may progress to cause total loss of hair on the head or total loss of hair all over the body including head.
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Alopecia totalis
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Alopecia areata totalis (AAT) is a rare severe hair loss. In this type there is total loss of hair on the head. Autoimmunity is considered to be the cause of this disorder. In many cases the hair regrows. Methotrexate, an antimetabolite and antifolate drug used for some autoimmune diseases and cancer may suppress the disorder.
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Alopecia universalis
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Alopecia areata universalis (AAU) is also a rare and severe hair loss. In this type hair fall is rapid and there is total hair loss from the body including head, eyelashes and eyebrows. The condition may appear at any age and in both the genders. The condition may resolve fast and the hair may start regrowing. In some individuals the regrowth may start after several years and in some it may not regrow at all. AAU is believed to be a autoimmune disorder.
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Alopecia barbae
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This is a condition affecting only men wherein alopecia areata is restricted to the beard. This is again an autoimmune condition wherein the body's immune mechanism mistakenly destroys or suppresses the hair follicles.
Alopecia mucinosa
Alopecia mucinosa (follicular mucinosis) is rare skin disorder with characteristic hairless scaly pink, flat patches without hair on the scalp and face. When observed under microscope, mucin is seen deposited around hair follicles. The exact cause of alopecia mucinosa is not known and cell mediated immunity may be the causative factor.
Anagen effluvium
Anagen effluvium is loss of hair under growth phase.
Primarily This type of alopecia is caused by chemotherapy and radiation therapy. In most of the individuals the hair grows after the cessation of the therapy.
Telogen effluvium
Telogen effluvium is the loss of hair during the telogen phase (hair follicle resting phase). Usually emotional or physical stress is the cause of this type of alopecia. prolonged febrile illness, childbirth, major surgery, chemicals and drugs can be the causative factors.
Scarring Alopecia
Cicatricial alopecia (aka scarring alopecia) is a group of hair loss conditions wherein the hair follicles are destroyed and replaced by scar tissue. The scar may be apparent or invisible and deeper inside the skin. The hair loss is permanent. This type of alopecia can affect both men and women. The causes are inflammatory diseases affecting the hair follicles where the stem cells and sebaceous glands are located. With the destruction of stem cells and sebaceous glands there is no regeneration of follicles. Hair follicle destructive inflammatory process and external injuries such as severe scalp infections, burns, radiation, tumors, and traction are some of the causative factors.
Traction Alopecia
Traction Alopecia is a type of alopecia caused by application of pulling force. Wearing tight pigtails, ponytail or braids causes the hairline to recede due to constant hair pulling. Extended use of hairpiece, wig, headgear or tightly fitting safety helmet may also cause this type of alopecia.
Trichotillomania
Trichotillomania is hair pulling disorder. The affected individuals have a compulsive urge to pull out their own hair. In this type of alopecia patches of hair loss occur. It is a psychological disorder and may get triggered by stress and depression. Affected individuals have tendency to keep pulling hair from head, eyelashes, eyebrows, nose and hands. Most of the patients with trichotillomania do not realize that they are pulling their hair. If the disorder is present in childhood, the child may outgrow the habit. If this type of habit persists a psychiatrist may be consulted for behavioral evaluation and treatment.
Pressure alopecia
Pressure alopecia is often seen in infants and bedridden patients. Lying in the same position and constant pressure on the rear of the head causes alopecia.
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Imagesource: http://en.wikipedia.org/wiki/File:Alopecia.jpg
Author: Welshsk | License: CC BY 3.0
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Reference:
1.Camacho-MartÃnez FM. Hair loss in women. Semin Cutan Med Surg. 2009 Mar;28(1):19-32. doi: 10.1016/j.sder.2009.01.001.
2.Banka N, Bunagan MJ, Shapiro J. Pattern hair loss in men: diagnosis and medical treatment. Dermatol Clin. 2013 Jan;31(1):129-40. doi: 10.1016/j.det.2012.08.003. Epub 2012 Sep 21.
3.Sinclair R, Patel M, Dawson TL Jr, Yazdabadi A, Yip L, Perez A, Rufaut NW. Hair loss in women: medical and cosmetic approaches to increase scalp hair fullness. Br J Dermatol. 2011 Dec;165 Suppl 3:12-8. doi: 10.1111/j.1365-2133.2011.10630.
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