Hair Loss Syndromes
Hair loss syndromes
Hair loss syndromes are a varied group of disorders and conditions characterized by the gradual or sudden loss of large amounts of hair—most often from the scalp, but sometimes from other areas of the body. Hair loss (or baldness) is sometimes referred to as alopecia. Madarosis is the medical term for the loss of eyelashes (ciliary madarosis) or eyebrows (superciliary madarosis).
Genetic factors are the most common cause of alopecia. Although hair loss, unlike some genetic disorders , is not a life-threatening or disabling condition, it often has painful psychological consequences. Good grooming and an attractive appearance are important factors in the contemporary job market as well as interpersonal relationships, and a full head of hair is considered a positive feature. Historically, men have tended to put less weight on their external appearance than women have, but this pattern has changed in the last two decades. Present evidence indicates that men are now as vulnerable to pressures to "look good" as women are, and that hair loss is a frequent focus of men's concerns about their looks. American men spend over two billion dollars each year on hair-replacement products.
Hair loss syndromes can be divided into two major categories, those caused by some type of inflammation, and those caused by genetic factors, aging, or medication side effects. The noninflammatory syndromes are subdivided into two groups according to the pattern of hair loss. The inflammatory syndromes are also subdivided into two groups according to the presence or absence of tissue destruction.
Noninflammatory patterned hair loss
ANDROGENETIC ALOPECIA Androgenetic alopecia is the most common hair loss syndrome, covering about 95% of cases of hair loss. It is also referred to as androgen-dependent or genetic hair loss. In order to understand this form of alopecia, it is useful to begin with some basic facts about the structure and growth cycle of human hair. Hair is composed primarily of keratin, a tough protein that is also found in the fingernails, toenails, and the outermost layer of skin. Each individual hair consists of a hair follicle, which is a small sac that produces the hair shaft, and the hair shaft itself. The average adult scalp contains about 100,000 hair follicles, the number depending on the natural color of the hair. Brunettes have the highest number of scalp follicles (about 155,000), followed by blondes (140,000) and redheads (85,000). The average adult loses between 70 and 100 scalp hairs per day from ordinary combing, brushing, or shampooing. A loss of more than 150 hairs per day is abnormal.
Human hair differs from the hair of other animals in that its growth cycle is not synchronized; an examination of a group of scalp hairs from the same part of the scalp will show that they are in different phases of growth. There are three phases in the human hair growth cycle. Hairs in the anagen, or growth, stage remain in the follicle during an average period of two to eight years, and grow between a quarter-inch and a half-inch per month. About 90% of scalp hairs are in the anagen phase at any one time. At the end of the anagen phase, the hair enters a brief catagen phase lasting between two and four weeks. During this phase the follicle begins to break down. The catagen phase is followed by a telogen, or resting, phase that lasts between two and four months. Hairs in the telogen phase are shed when the growth phase of the next cycle begins and the new hair shaft pushes out the old hair. About 10% of the hairs on the scalp are normally in the telogen phase. These hairs will regrow about six months after they have been shed.
What happens in androgenetic baldness is that the hair growth cycle is affected by the rise in the level of androgens (male sex hormones) in the body that occurs at puberty. Women as well as men produce androgens, although in much smaller amounts. The amount of these hormones does not need to be abnormally high for androgenetic hair loss to occur. Males who have a normal level of androgens and a gene for baldness will develop male pattern hair loss, or MPHL. There are two androgens that contribute to MPHL, dihydrotestosterone (DHT) and testosterone. Testosterone is converted to DHT by an enzyme called 5-alpha-reductase. In men with genes for baldness, the hair follicles in the scalp remove testosterone from circulation and convert it to DHT. The action of DHT over time shortens the duration of the anagen phase of the hair growth cycle and decreases the proportion of the hairs in the anagen phase. As the anagen phase decreases, the hairs produced are shorter in length and thinner in diameter. As a larger percentage of the hairs are in the resting or telogen phase, more are lost during normal grooming. This process of the shortening and thinning of each hair shaft is called miniaturization. Miniaturization is accompanied by the loss of hair pigment production, so that the miniaturized hairs are also lighter in color. The light-colored fine hairs that are left at the end of the miniaturization process are called vellus hairs.
In MPHL, hair loss tends to occur in certain areas rather than being distributed evenly over the head. One common pattern is recession of the hair at the temples, with the man's hairline moving backward over time in an "M" pattern. The hair at the crown of the head also begins to thin, and may meet the receding hairline so that the remaining hair forms the rough outline of a horseshoe.
In female pattern hair loss, or FPHL, there is an overall thinning of the hair as well as more pronounced hair loss in certain areas of the scalp, usually the crown. Women with FPHL may find that their hairlines recede a little, but rarely to the same extent as happens in men. Androgens play the same role in hair loss in women that they do in men, since the adrenal glands and ovaries secrete small amounts of androgens.
There are other important differences between FPHL and MPHL:
- FPHL generally appears at later ages, in the woman's late twenties or early thirties, whereas MPHL can affect boys as young as 15.
- FPHL is frequently associated with hormonal changes in women, such as those that occur after childbirth; with the use of birth control pills; or after menopause.
- Women very rarely experience complete loss of hair from a specific area of their scalp due to FPHL. The process of miniaturization in FPHL affects the hair follicles at random, so that some hairs are unaffected. These normal thick hairs are interspersed among thinner, miniaturized hairs.
TRACTION ALOPECIA Traction alopecia is a noninflammatory patterned hair loss syndrome in which the pattern of loss is related to pulling or friction on specific areas of the scalp. It is usually caused either by hair styles in which the hair is pulled into tight braids or held too tightly by rubber bands, or by frequent use of electronic headsets (e.g., Walkman radios, hands-free telephones, etc.) for long periods of time. The tension or rubbing damages the hair shafts and hinders the growth of new hair. In some cases the use of tight hair rollers at night or frequent use of blow dryers on high settings contributes to hair loss from traction alopecia.
TRICHOTILLOMANIA Trichotillomania is a psychiatric disorder that results in patterned hair loss. It is characterized by recurrent episodes of pulling or tugging at the hair in order to relieve stress or tension. The most commonly affected areas are the scalp, the eyebrows, and the eyelashes, although some patients with the disorder pull at hair elsewhere on the body. Trichotillomania can usually be differentiated from other hair loss syndromes by laboratory study of a hair sample.
Noninflammatory diffuse hair loss
TELOGEN EFFLUVIUM Telogen effluvium is a common cause of diffuse hair loss, which means that hairs are shed from all parts of the scalp, not just certain patterned areas. Effluvium is a Latin word that means "outflow," and refers to the large amounts of hair that may be lost. Persons affected by telogen effluvium may lose as much as 30%-40% of their hair in a short period of time.
Telogen effluvium results from an abnormal alteration of the hair growth cycle, in which large numbers of hairs in the anagen phase suddenly switch into the telogen phase. Within six weeks to four months after this switch, these hairs begin to shed.
There are number of possible causes for telogen effluvium, including:
- Major surgery.
- Pregnancy and childbirth.
- Crash dieting.
- Nutritional deficiencies, including iron deficiency.
- Malabsorption syndrome.
- Infectious diseases accompanied by high fever, such as scarlet fever, early syphilis, or typhoid.
- Medications. A number of medications are known to cause telogen effluvium, including beta blockers; oral contraceptives; retinoids; nonsteroidal anti-inflamma-tory agents (NSAIDs), such as indomethacin (Indocin) and ibuprofen (Advil); aspirin and other salicylates; lithium; anticoagulants (blood thinners); and anti-convulsants (medications for seizures).
Telogen effluvium usually stops after a few months and new hair grows in. The first regrowth may be finer than usual but the follicles will eventually produce hair of normal thickness.
ANAGEN EFFLUVIUM Anagen effluvium is a type of diffuse hair loss resulting from a sudden interruption of the growth phase. Unlike the time lag that characterizes telogen effluvium, hair loss in anagen effluvium occurs at once. The most common cause of anagen effluvium is chemotherapy, including treatment with methotrexate, bleomycin, vinblastine, vincristine, cyclophosphamide, doxorubicin, daunorubicin, and cytarabine. This form of hair loss, however, can also be caused by poisoning with arsenic, thallium, bismuth, or borax.
Anagen effluvium usually stops as soon as the chemical cause is removed, but it may take several months for hair to regrow completely.
Inflammatory nonscarring hair loss
ALOPECIA AREATA Alopecia areata is a nonscarring recurrent form of hair loss characterized by smooth round or oval patches of bare skin. There may be some mild itching but no visible skin eruptions. Alopecia areata is usually considered an idiopathic disorder, which means its cause is unknown. Some researchers, however, consider it an autoimmune disorder. It is often triggered by stress or anxiety. Alopecia areata usually affects only the scalp, the eyebrows, and (in men) the beard, but may cause hair loss over the entire scalp (alopecia totalis) or even the entire body (alopecia universalis). The loss of hairs from the eyebrows and eyelashes that may be associated with alopecia totalis is called madarosis.
PSORIASIS Psoriasis is a chronic inflammatory skin disease that frequently affects the elbows and knees as well as the scalp. On the scalp, psoriasis is marked by the appearance of red plaques or patches with silvery scales. These patches may also be found behind the ears. Psoriasis can cause massive but temporary hair loss.
Inflammatory scarring hair loss
In hair loss syndromes marked by tissue scarring, the hair loss is permanent and irreversible. These syndromes should be diagnosed as quickly as possible to minimize the extent of damaged tissue.
LUPUS ERYTHEMATOSUS Lupus erythematosus is an autoimmune disorder than can affect a number of different organ systems. About 85% of lupus patients are women between 20 and 40 years of age. More than 10% of women with lupus develop a form of the disorder known as chronic discoid or chronic cutaneous lupus erythematosus. Chronic discoid lupus can occur on the scalp as well as the face, and is marked by dark red patches or plaques between 0.5 in (1.3 cm) and 0.75 in (1.9 cm) in diameter. The plaques are covered by dry, horny scales that plug the hair follicles and cause permanent hair loss.
LICHEN PLANOPILARIS Lichen planopilaris is a form of lichen planus, an idiopathic recurrent skin disorder that usually affects the wrists, legs, and mucous membranes. It is characterized by itching pinkish-red or purplish patches or pimples on the scalp. Like lupus, lichen planopilaris can cause lasting hair loss.
BACTERIAL OR FUNGAL INFECTIONS Scarring alopecia can be caused by dermatophytes, which are fungi that live on the skin and hair. These fungi include Trichophyton rubrum, Trichophyton tonsurans, and Microsporum audouinii. The dermatophytes infect the skin of the scalp and move down the hair shaft into the follicle, which may be permanently destroyed.
SCLERODERMA Scleroderma is a chronic disorder in which the patient's skin and connective tissue become progressively thicker and more rigid. Its cause is not known. As the patient's scalp thickens, the hair is gradually but permanently lost.
INJURIES Scarring alopecia can also result from burns, trauma to the scalp, or radiation treatment.
Male pattern hair loss (MPHL)
Male pattern hair loss (MPHL) is a polygenic disorder, which means that its appearance is directed by more than one gene. It may be inherited from either the father's or mother's side. The belief that MPHL is inherited only through the mother is a myth. Genes for baldness are, however, dominant, which means that 50% of the children of a balding parent of either sex will inherit the baldness genes. Genetic factors appear to influence the age at onset of MPHL; the extent and speed of hair loss; and the pattern of hair loss. MPHL may begin at any time after the levels of androgens in a boy's blood begin to rise during puberty.
It is important to note that genes for baldness depend on normal levels of androgen in the body to produce androgenetic hair loss. Men who were castrated prior to puberty, or have abnormally low levels of androgen for other reasons, do not go bald even if they have a gene for baldness.
Female pattern hair loss (FPHL)
Female pattern hair loss, or FPHL, is also a dominant disorder. At present, however, there is some disagreement as to whether it runs in families to the same extent as MPHL.
About 20% of cases of alopecia areata are thought to have a genetic component.
Androgenetic alopecia is quite widespread in the general United States population. It is estimated that 35 million American men are affected by this hair loss syndrome. About 25% of Caucasian men begin to show signs of baldness by the time they are thirty, and 67% are either bald or developing a balding pattern by age 60. The first evidence of hair loss, namely a receding hair line at the temples, can be found in 96% of Caucasian males over age 15, including those who will not lose any more hair.
There is less agreement on the incidence of androgenetic alopecia among women in the United States; estimates range from 8% to 87%. A commonly accepted figure is that 21 million women are affected. About 80% of girls begin to show some loss of hair at the hairline during puberty, including some who will not develop FPHL.
About 2.5 million people in the United States suffer from alopecia areata. It appears to affect men and women equally.
Trichotillomania was once thought to be an uncommon disorder, but more recent research suggests that it occurs fairly frequently among adolescents and young adults. Surveys of college students indicate that 1%-2% are or have been affected by trichotillomania. The male/female ratio is 1:1 in children, but is about 1:4 in college students. The disorder may be underdiagnosed in males because their hair loss is attributed to MPHL.
Signs and symptoms
The signs and symptoms of each hair loss syndrome are included in its description.
The differential diagnosis of hair loss is usually made on the basis of the patient's history, visual examination of the scalp, and the results of laboratory tests. The more common forms of alopecia can be diagnosed by a family physician, but those that are related to skin disorders may require referral to a dermatologist. There are four key questions that the doctor will ask in evaluating hair loss:
- How long has the patient been losing hair?
- Is there a pattern to the remaining hair?
- Is the hair loss associated with redness, itching, or pain?
- Are there any patches of broken skin, pimples, plaques, or other signs of infection in the affected areas?
The patient's medical history may contain information about previous episodes of hair loss; eating and nutritional habits; use of prescription medications; surgery or chemotherapy; occupational exposure to arsenic, thallium, or bismuth; recent illnesses with high fevers; recent periods of severe emotional stress or anxiety; or other factors that may influence hair loss. In addition, the doctor will ask about grooming habits, including the use of dyes, home permanents, hair straighteners, hair sprays, and similar products as well as blow dryers, rollers, and other hair styling equipment.
Laboratory tests are performed on samples of the hair itself as part of the differential diagnosis. Microscopic study of a hair sample will indicate, for example, damage to the hair shaft, broken hairs, and changes in the shape of the hair. For example, broken hairs may suggest traction alopecia or trichotillomania. In trichotillomania, there will also be an unusually high number of hairs in the catagen phase. Anagen effluvium produces hairs with tapered or pointed ends, sometimes called "pencil-point" hairs. In telogen effluvium, the hairs have white bulbs at the end and can often be removed from the head by very gentle pulling. In alopecia areata, the area of hair loss is bordered by telltale "exclamation point" hairs.
Hair samples can also be subjected to chemical analysis if heavy metal poisoning is suspected. Arsenic and thallium are absorbed by the hair shaft and can be detected by appropriate tests.
Skin biopsies are most useful in diagnosis when an infection or other inflammatory condition is suspected as the cause of the hair loss. While scarring can often be seen during a visual examination of the scalp, a biopsy may be the only way to tell if the hair follicles have been destroyed, as well as to differentiate among lupus, dermatophyte infection, alopecia areata, and scleroderma. Biopsies may also be useful in determining the presence of traction alopecia or trichotillomania. In these conditions, pieces of hair shaft are sometimes found in the surrounding skin. Some hair follicles may show signs of injury and are interspersed among normal follicles.
Treatment and management
The treatment of hair loss syndromes is determined by their causes.
TOPICAL APPLICATIONS Topical applications for hair loss syndromes fall into two major categories—those that stimulate the growth of new hair and those that reduce inflammation. The most frequently prescribed topical medication for male pattern hair loss is minoxidil, which was originally developed to lower high blood pressure. It was approved by the FDA for the treatment of androgenetic hair loss in 1988. Minoxidil, sold under the trade name Rogaine, is applied twice a day as a 2% or 5% solution. Rogaine is also sometimes prescribed for female pattern hair loss and alopecia areata. Its chief drawback is its high cost—it costs between $650 and $700 a year to use Rogaine twice a day.
Alopecia areata may be treated with topical corticosteroids, or with injections of triamcinolone acetonide (Kenalog) in the affected areas every three or four weeks. Topical corticosteroids are also used to treat chronic discoid lupus, lichen planopilaris, and psoriasis. Tar shampoos are frequently recommended along with topical steroids to treat psoriasis of the scalp.
ORAL MEDICATIONS One oral medication, finasteride, has been approved by the FDA since 1997 for the treatment of male pattern hair loss. Finasteride, sold under the trade names Propecia or Proscar, works by interfering with the body's production of 5-alpha-reduc-tase, the enzyme that converts testosterone to DHT. It is considered the most effective nonsurgical treatment of MPHL. The usual daily dose of finasteride is 1 mg. Unlike minoxidil, finasteride does not appear to be effective in postmenopausal women. It has not been tested on women of childbearing age because its androgen content could cause birth defects in male children.
Oral antifungal medications are considered better than topical preparations for treating dermatophyte infections of the scalp because topical products do not penetrate around the hair follicle. The mostly commonly prescribed oral antifungal drugs are griseofulvin (Grisactin, Fulvicin), ketoconazole (Nizoral), and fluconazole (Diflucan).
Clomipramine (Anafranil), which is a tricyclic antidepressant, or fluoxetine (Prozac), a selective serotonin reuptake inhibitor (SSRI), have been used in the treatment of trichotillomania.
Surgical transplantation is considered the most effective treatment of MPHL, but is not recommended for alopecia areata. Punch grafts or larger skin flaps bearing the patient's own hair are transferred from areas of the head with normal hair growth to the balding areas. Hair transplantation is expensive but is usually permanent. It appears to work best on patients with dark or curly hair.
Scalp reduction is another surgical technique used in treating MPHL, in which bald areas at the top of the scalp are removed. It works best for patients with relatively little hair loss.
Non-surgical hair additions
These devices consist of human hair, synthetic fibers, or combinations of both. They are added to existing hair or attached to the scalp with adhesives to cover areas of hair loss. They include hair weaves, hair pieces, hair extensions, toupees, partial hair prostheses, and similar devices. Non-surgical hair additions are less expensive than surgery but still cost between $750 and $2500, depending on materials and design. They can be used in combination with hair replacement surgery.
Cognitive-behavioral therapy is considered the most effective form of psychotherapy in treating trichotillomania. Individual psychodynamic psychotherapy is often helpful for persons who are emotionally upset by hair loss, particularly those whose employment depends on their appearance.
The prognoses of hair loss syndromes vary according to their causes. Hair loss caused by inflammatory scarring has the worst prognosis, as syndromes or injuries that form scar tissue destroy the hair follicles, preventing regrowth. The prognosis for alopecia areata is less favorable if the disorder affects large areas of the scalp, begins in adolescence, or has existed for a year or longer before the patient seeks treatment. Alopecia areata that begins in adult life and is limited to a few small areas of the scalp often goes away by itself in a few months, although the condition can recur. Diffuse hair loss related to anagen or telogen effluvium has a good prognosis; although complete regrowth may take some months, the hair does come back once the cause is identified and removed.
The prognosis for androgenetic alopecia varies. Rogaine does not work equally well for all men with MHPL. Those who benefit most from treatment with Rogaine have been bald for less than ten years; have a bald spot on the crown of the head that is smaller than 4 inches across; and still have vellus hairs in their balding areas. In addition, hair that grows in as a result of Rogaine will fall out once the patient stops using it. Finasteride is becoming the first-line nonsurgical treatment for MPHL because it prevents hair loss as well as aiding regrowth; one study indicates that finasteride prevents further loss of hair in 90% of men even five years after they take it, and assists regrowth in 65% of men even two years later.
"Alopecia." The Merck Manual of Diagnosis and Therapy. Edited by Mark H. Beers, MD, and Robert Berkow, MD. Whitehouse Station, NJ: Merck Research Laboratories, 1999.
American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. 4th ed. Washington, DC: American Psychiatric Association, 1994.
Helm, Thomas N., MD. "Hair Disorders." Conn's Current Therapy. Edited by Robert E. Rakel, MD. Philadelphia: W. B. Saunders Company, 2000.
American Academy of Dermatology. PO Box 4014, 930 N. Meacham Rd., Schaumburg, IL 60168-4014. (847) 330-0230. Fax: (847) 330-0050. <http://www.aad.org>.
American Society for Dermatologic Surgery. 1567 Maple Ave., Evanston, IL 60201. (708) 869-3954.
Dept. of Health and Human Services. Public Health Service, FDA, 5600 Fishers Lane, Rockville, MD 20857.
National Alopecia Areata Foundation (NAAF). PO Box 150760, San Rafael, CA 94915-0760. (415) 456-4644.
Food and Drug Administration consumer affairs. <http://vm.cfsan.fda.gov/~dms/cos>.
International Society of Hair Restoration Surgery. <http://www.ishrs.org>.
Rebecca J. Frey, PhD