Alopecia
Encyclopedia
Alopecia 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 produce hair loss. Hairstyling routines such as tight ponytails or braids may induce 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
.
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 in to the effects that occur with chemotherapy
.
In male-pattern hair loss, loss and thinning begin at the temples and either thins out or falls out. Female-pattern hair loss occurs when hair thinning occurs at the frontal
and parietal
.
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 100 hairs reach the end of their resting phase each day and fall out. When more than 100 hairs fall out per day, clinical hair loss (telogen effluvium
) may occur. A disruption of the growing phase causes abnormal loss of anagen hairs (anagen effluvium
).
, SOX21
, that appears to be responsible for hair loss in humans and a researcher in India found the missing link between androgenic hormone and hair loss. Androgenic alopecia is said to be a counterproductive outcome of the anabolic effect of androgens.
Hair
Hair is a filamentous biomaterial, that grows from follicles found in the dermis. Found exclusively in mammals, hair is one of the defining characteristics of the mammalian class....
from the head or body. Alopecia can mean baldness
Baldness
Baldness implies partial or complete lack of hair and can be understood as part of the wider topic of "hair thinning". The degree and pattern of baldness can vary greatly, but its most common cause is male and female pattern baldness, also known as androgenic alopecia, alopecia androgenetica or...
, a term generally reserved for pattern alopecia or androgenic alopecia. Compulsive pulling of hair (trichotillomania
Trichotillomania
Trichotillomania, which is classified as an impulse control disorder by DSM-IV, is the compulsive urge to pull out one's own hair leading to noticeable hair loss, distress, and social or functional impairment. It is often chronic and difficult to treat....
) can also produce hair loss. Hairstyling routines such as tight ponytails or braids may induce Traction alopecia
Traction alopecia
Traction alopecia is a form of alopecia, or gradual hair loss, caused primarily by pulling force being applied to the hair. This commonly results from the sufferer frequently wearing his/her hair in a particularly tight ponytail, pigtails, or braids...
. 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
Iron deficiency (medicine)
Iron deficiency is one of the most common of the nutritional deficiencies. Iron is present in all cells in the human body, and has several vital functions...
.
Generally, hair loss in patches signifies alopecia areata
Alopecia areata
Alopecia areata is a medical condition in which hair is lost from some or all areas of the body, usually from the scalp. Because it causes bald spots on the scalp, especially in the first stages, it is sometimes called spot baldness. In 1–2% of cases, the condition can spread to the entire scalp ...
. 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
Alopecia totalis
Alopecia totalis is the loss of all head hair. Its causes are unclear, but it is currently believed to be an autoimmune disorder. Stress is sometimes thought to be a contributor in alopecia areata...
. When the entire body suffers from complete hair loss, it is referred to as alopecia universalis
Alopecia universalis
Alopecia universalis or alopecia areata universalis is a medical condition involving rapid loss of all hair, including eyebrows and eyelashes. It is the most severe form of alopecia areata, with an incidence of .001%...
. It is similar in to the effects that occur with chemotherapy
Chemotherapy
Chemotherapy is the treatment of cancer with an antineoplastic drug or with a combination of such drugs into a standardized treatment regimen....
.
Signs and symptoms
When examining the scalp, the distribution of hair loss, presence and characteristics of skin lesions, and the presence of scarring should be noted. Part widths should be measured. All abnormalities should be noted.In male-pattern hair loss, loss and thinning begin at the temples and either thins out or falls out. Female-pattern hair loss occurs when hair thinning occurs at the frontal
Frontal lobe
The frontal lobe is an area in the brain of humans and other mammals, located at the front of each cerebral hemisphere and positioned anterior to the parietal lobe and superior and anterior to the temporal lobes...
and parietal
Parietal lobe
The parietal lobe is a part of the Brain positioned above the occipital lobe and behind the frontal lobe.The parietal lobe integrates sensory information from different modalities, particularly determining spatial sense and navigation. For example, it comprises somatosensory cortex and the...
.
Causes
- Alopecia mucinosaAlopecia mucinosaAlopecia mucinosa generally presents, but not exclusively, as erythematous plaques or flat patches without hair primarily on the scalp and face....
- Androgenic alopecia
- Dissecting Cellulitis
- Fungal Infections (such as tinea capitisTinea capitisTinea capitis is a superficial fungal infection of the scalp. The disease is primarily caused by dermatophytes in the Trichophyton and Microsporum genera that invade the hair shaft...
) - Hair Treatments (chemicals in relaxers, hair straighteners)
- Hereditary Disorder
- Hormonal Changes
- HyperthyroidismHyperthyroidismHyperthyroidism is the term for overactive tissue within the thyroid gland causing an overproduction of thyroid hormones . Hyperthyroidism is thus a cause of thyrotoxicosis, the clinical condition of increased thyroid hormones in the blood. Hyperthyroidism and thyrotoxicosis are not synonymous...
and HypothyroidismHypothyroidismHypothyroidism is a condition in which the thyroid gland does not make enough thyroid hormone.Iodine deficiency is the most common cause of hypothyroidism worldwide but it can be caused by other causes such as several conditions of the thyroid gland or, less commonly, the pituitary gland or... - Hypervitaminosis AHypervitaminosis AHypervitaminosis A refers to the effects of excessive vitamin A intake.-Presentation:Effects include* Birth defects* Liver problems* Reduced bone mineral density that may result in osteoporosis* Coarse bone growths...
- Iron deficiencyIron deficiency (medicine)Iron deficiency is one of the most common of the nutritional deficiencies. Iron is present in all cells in the human body, and has several vital functions...
- Lupus ErythematosusLupus erythematosusLupus erythematosus is a category for a collection of diseases with similar underlying problems with immunity . Symptoms of these diseases can affect many different body systems, including joints, skin, kidneys, blood cells, heart, and lungs...
- Medications (side effects from drugs, such as chemotherapyChemotherapyChemotherapy is the treatment of cancer with an antineoplastic drug or with a combination of such drugs into a standardized treatment regimen....
) - Pseudopelade of BrocqPseudopelade of BrocqPseudopelade of Brocq is a flesh- to pink-colored, irregularly shaped alopecia that may begin in a moth-eaten pattern with eventual coalescence into larger patches of alopecia.-See also:* Cicatricial alopecia...
- Radiation therapyRadiation therapyRadiation therapy , radiation oncology, or radiotherapy , sometimes abbreviated to XRT or DXT, is the medical use of ionizing radiation, generally as part of cancer treatment to control malignant cells.Radiation therapy is commonly applied to the cancerous tumor because of its ability to control...
- Scalp infection
- Secondary syphilisSyphilisSyphilis is a sexually transmitted infection caused by the spirochete bacterium Treponema pallidum subspecies pallidum. The primary route of transmission is through sexual contact; however, it may also be transmitted from mother to fetus during pregnancy or at birth, resulting in congenital syphilis...
- Telogen effluviumTelogen effluviumTelogen effluvium is a scalp disorder characterized by thinning/shedding of hair resulting from the early entry of hairs into the telogen phase.Emotional or physiological stressful events may result in an alteration of the normal hair cycle....
- Traction alopeciaTraction alopeciaTraction alopecia is a form of alopecia, or gradual hair loss, caused primarily by pulling force being applied to the hair. This commonly results from the sufferer frequently wearing his/her hair in a particularly tight ponytail, pigtails, or braids...
- TrichotillomaniaTrichotillomaniaTrichotillomania, which is classified as an impulse control disorder by DSM-IV, is the compulsive urge to pull out one's own hair leading to noticeable hair loss, distress, and social or functional impairment. It is often chronic and difficult to treat....
- Tufted folliculitisTufted folliculitisTufted folliculitis presents with doll's hair-like bundling of follicular units, and is seen in a wide range of scarring conditions including chronic staphylococcal infection, chronic lupus erythematosus, lichen planopilaris, Graham-Little syndrome, folliculitis decalvans, acne keloidalis nuchae,...
Pathophysiology
Hair follicleHair follicle
A hair follicle is a skin organ that produces hair. Hair production occurs in phases, including a growth phase , and cessation phase , and a rest phase . Stem cells are principally responsible for the production of hair....
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 100 hairs reach the end of their resting phase each day and fall out. When more than 100 hairs fall out per day, clinical hair loss (telogen effluvium
Telogen effluvium
Telogen effluvium is a scalp disorder characterized by thinning/shedding of hair resulting from the early entry of hairs into the telogen phase.Emotional or physiological stressful events may result in an alteration of the normal hair cycle....
) may occur. A disruption of the growing phase causes abnormal loss of anagen hairs (anagen effluvium
Anagen effluvium
Anagen effluvium is the pathologic loss of anagen or growth-phase hairs. Classically, it is caused by radiation therapy to the head and systemic chemotherapy, especially with alkylating agents....
).
Diagnosis
Evaluation for causative disorders should be done based on clinical symptoms. Because they are not usually associated with an increased loss rate, male-pattern and female-pattern hair loss don’t generally require testing. If hair loss occurs in a young man with no family history, the physician should question the patient on drug and illicit drug use.- The pull test: this test helps to evaluate diffuse scalp hair loss. Gentle traction is exerted on a group of hair (about 40–60) on three different areas of the scalp. The number of extracted hairs is counted and examined under a microscope. Normally, <3 hairs per area should come out with each pull. If >10 hairs are obtained, the pull test is considered positive.
- The pluck test: In this test, the individual pulls hair out “by the roots.” The root of the plucked hair is examined under a microscope to determine the phase of growth and used to diagnose a defect of telogen, anagen, or systemic disease. Telogen hairs are hairs that have tiny bulbs without sheaths at their roots. Telogen effluvium shows an increased percentage of hairs upon examination. Anagen hairs are hairs that have sheaths attached to their roots. Anagen effluvium shows a decrease in telogen-phase hairs and an increased number of broken hairs.
- Scalp biopsy: This test is done when alopecia is present, but the diagnosis is unsure. The biopsy allows for differing between scarring and nonscarring forms. Hair samples are taken from areas of inflammation, usually around the border of the bald patch.
- Daily Hair Counts: This is normally done when the pull test is negative. It is done by counting the number of hairs lost. The hair that should be counted are the hairs from the first morning combing or during washing. The hair is collected in a clear plastic bag for 14 days. The strands are recorded. If the hair count is >100/day, it is considered abnormal except after shampooing, where hair counts will be up to 250 and be normal.
- TrichoscopyTrichoscopyTrichoscopy is a method of hair and scalp evaluation and is used for diagnosing hair and scalp diseases. The method is based on dermoscopy and videodermoscopy. In trichoscopy hair and scalp structures may be visualized at many-fold magnification...
: Trichoscopy is a non-invasive method of examining hair and scalp. The test may be performed with the use of a handheld dermoscope or a video dermoscope. It allows differential diagnosis of hair loss in most cases.
Treatment
- Minoxidil (Rogaine)MinoxidilMinoxidil is an antihypertensive vasodilator medication which also slows or stops hair loss and promotes hair regrowth. Now off-patent, it is available over-the-counter for the treatment of androgenic alopecia. Minoxidil must be used indefinitely for continued support of existing hair follicles and...
: This is a non-prescription medication approved for androgenetic alopecia and alopecia areata. Minoxidil comes in a liquid or foam that is rubbed into the scalp twice a day. This is the most effective method to treat male-pattern and female-pattern hair loss . However, only 30–40% of patients experience hair growth. Minoxidil is not effective for other causes of hair loss except alopecia areata. Hair regrowth can take 8 to 12 months. Treatment is continued indefinitely because if the treatment is stopped, hair loss resumes again. Most frequent side effects are mild scalp irritation, allergic contact dermatitisAllergic contact dermatitisAllergic contact dermatitis is a form of contact dermatitis that is the manifestation of an allergic response caused by contact with a substance....
, and increased facial hair. - Finasteride (Propecia)FinasterideFinasteride is a synthetic antiandrogen that inhibits type II 5-alpha reductase, the enzyme that converts testosterone to dihydrotestosterone...
: Is used in male-pattern hair loss in a pill form taken on a daily basis. Finasteride is not indicated for women and is not recommended in pregnant women. Treatment is effective within 6 to 8 months of treatment. Side effects include decreased libidoLibidoLibido refers to a person's sex drive or desire for sexual activity. The desire for sex is an aspect of a person's sexuality, but varies enormously from one person to another, and it also varies depending on circumstances at a particular time. A person who has extremely frequent or a suddenly...
, erectile dysfunctionErectile dysfunctionErectile dysfunction is sexual dysfunction characterized by the inability to develop or maintain an erection of the penis during sexual performance....
, ejaculatory dysfunction, gynecomastiaGynecomastiaGynecomastia or Gynaecomastia, , is the abnormal development of large mammary glands in males resulting in breast enlargement. The term comes from the Greek γυνή gyné meaning "woman" and μαστός mastós meaning "breast"...
, and myopathyMyopathyIn medicine, a myopathy is a muscular disease in which the muscle fibers do not function for any one of many reasons, resulting in muscular weakness. "Myopathy" simply means muscle disease...
. Treatment should be continued as long as positive results occur. Once treatment is stopped, hair loss resumes again. - CorticosteroidsCorticosteroidCorticosteroids are a class of steroid hormones that are produced in the adrenal cortex. Corticosteroids are involved in a wide range of physiologic systems such as stress response, immune response and regulation of inflammation, carbohydrate metabolism, protein catabolism, blood electrolyte...
: Injections of cortisone into the scalp can be used to treat alopecia areata. This type of treatment is repeated on a monthly basis. Physician may prescribe oral pills for extensive hair loss due to alopecia areata. Results may take up to a month to be seen. - Anthralin (Dritho-Scalp)DithranolDithranol or Anthralin is a Hydroxyanthrone, anthracene derivative, medicine applied to the skin of people with psoriasis. It is available as creams, ointment or pastes in 0.1 to 2% strengths...
: Available as a cream or ointment that is applied to the scalp and washed off daily. More commonly is used to treat psoriasisPsoriasisPsoriasis is an autoimmune disease that appears on the skin. It occurs when the immune system mistakes the skin cells as a pathogen, and sends out faulty signals that speed up the growth cycle of skin cells. Psoriasis is not contagious. However, psoriasis has been linked to an increased risk of...
. Results may take up to 12 weeks to be seen. - Hormonal Modulators: Oral contraceptives or spironolactoneSpironolactoneSpironolactone , commonly referred to as simply spiro, is a diuretic and is used as an antiandrogen.It is a synthetic 17-lactone drug that is a renal competitive aldosterone antagonist in a class of pharmaceuticals called...
can be used for female-pattern hair loss associated with hyperandrogenemiaHyperandrogenismHyperandrogenism is a medical condition characterized by excessive production and/or secretion of androgens.It is one of the primary symptoms of polycystic ovary syndrome. In such cases, it presents with symptoms such as acne or hyperseborrhea, is frequent in adolescent girls and is often...
. - Surgical Options: Treatment options such as follicle transplant, scalp flaps, and alopecia reduction are available. These procedures are generally chosen by those who are self-conscious about their hair loss. These options are expensive and painful. There is a risk of infection and scarring. Once surgery has occurred, it takes 6 to 8 months before the quality of new hair can be assessed.
- Hair transplantHair transplantationHair transplantation is a surgical technique that involves moving individual hair follicles from one part of the body to bald or balding parts . It is primarily used to treat male pattern baldness. It this case, grafts containing hair follicles that are genetically resistant to balding are...
: 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: This 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.
- Wigs: As an alternative to medical and surgical treatment, some patients wear a wig or hairpiece. They can be used permanently or temporarily to cover the hair loss. Quality, and natural looking wigs and hairpieces are available.
Research
In May 2009, researchers in Japan identified a geneGene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
, SOX21
SOX21
Transcription factor SOX-21 is a protein that in humans is encoded by the SOX21 gene. It is a member of the Sox gene family of transcription factors.- Function :...
, that appears to be responsible for hair loss in humans and a researcher in India found the missing link between androgenic hormone and hair loss. Androgenic alopecia is said to be a counterproductive outcome of the anabolic effect of androgens.
See also
- BaldnessBaldnessBaldness implies partial or complete lack of hair and can be understood as part of the wider topic of "hair thinning". The degree and pattern of baldness can vary greatly, but its most common cause is male and female pattern baldness, also known as androgenic alopecia, alopecia androgenetica or...
- Androgenic alopecia – male pattern baldness
- Baldness treatmentsBaldness treatmentsBaldness treatment is a US $1 billion per year industry. In males past their early 20s, the incidence of balding is roughly equivalent to chronological age. Thus, by age 50, roughly half of men experience male pattern baldness . Beginning in the 1980s, drug therapy has increasingly become a...
- Lichen planopilarisLichen planopilarisLichen planopilaris is a form of hair loss which involves scarring, a follicular form of lichen planus, and is considered to have an autoimmune cause...