Alopecia

Alopecia 

Definition

Alopecia simply means hair loss (baldness).

Description

Hair loss occurs for a great many reasons, from conditions that make people literally pull it out to complete hair loss caused by the toxicity of cancer chemotherapy. Some causes are considered natural, while others signal serious health problems. Some conditions are confined to the scalp. Others reflect disease throughout the body. Being plainly visible, the skin and its components can provide early signs of disease elsewhere in the body.

Oftentimes, conditions affecting the skin of the scalp will result in hair loss. The first clue to the specific cause is the pattern of hair loss, whether it be complete baldness (alopecia totalis), patchy bald spots, thinning, or hair loss confined to certain areas. Also a factor is the condition of the hair and the scalp beneath it. Sometimes only the hair is affected; sometimes the skin is visibly diseased as well.

Causes and symptoms

Top of balding male's head.

(Photograph by Kelly A. Quin. Reproduced by permission.)

Diagnosis

Dermatologists are skilled in diagnosis by sight alone. For more obscure diseases, they may have to resort to a skin biopsy, removing a tiny bit of skin using a local anesthetic so that it can be examined under a microscope. Systemic diseases will require a complete evaluation by a physician, including specific tests to identify and characterize the problem.

Treatment

Successful treatment of underlying causes is most likely to restore hair growth, be it the completion of chemotherapy, effective cure of a scalp fungus, or control of a systemic disease. Two relatively new drugs—minoxidil (Rogaine) and finasteride (Proscar)—promote hair growth in a significant minority of patients, especially those with male pattern baldness and alopecia areata. While both drugs have so far proved to be quite safe when used for this purpose, minoxidil is a liquid that is applied to the scalp and finasteride is the first and only approved treatment in a pill form.

Key terms

Athlete's foot — A fungal infection between the toes, officially known as tinea pedis.

Autoimmune disease — Certain diseases caused by the body's development of an immune reaction to its own tissues.

Chemotherapy — The treatment of diseases, usually cancer, with drugs (chemicals).

Hair follicles — Tiny organs in the skin, each one of which grows a single hair.

Lupus erythematosus — An autoimmune disease that can damage skin, joints, kidneys, and other organs.

Ringworm — A fungal infection of the skin, usually known as tinea corporis.

Systemic — Affecting all or most parts of the body.

Minoxidil was approved for over-the-counter sales in 1996. When used continuously for long periods of time, minoxidil produces satisfactory results in about one-fourth of patients with androgenic alopecia and as many as half the patients with alopecia areata. There is also an over-the-counter extra-strength version of minoxidil (5% concentration) approved for use by men only. The treatment often results in new hair that is thinner and lighter in color. It is important to note that new hair stops growing soon after the use of minoxidil is discontinued.

Over the past few decades a multitude of hair replacement methods have been performed by physicians and non-physicians. They range from simply weaving someone else's hair in with the remains of one's own to surgically transplanting thousands of hair follicles one at a time.

Hair transplantation is completed by taking tiny plugs of skin, each containing one to several hairs, from the back side of the scalp. The bald sections are then implanted with the plugs. Research completed in 2000 looked at the new technique of hair grafting, and found that micrografts (one or two hairs transplanted per follicle) resulted in fewer complications and the best results.

Another surgical procedure used to treat androgenic alopecia is scalp reduction. By stretching skin, the hairless scalp can be removed and the area of bald skin decreased by closing the space with hair-covered scalp. Hair-bearing skin can also be folded over an area of bald skin with a technique called a flap.

Stem cell research is generating new hope for baldness. Scientists know that a part of the hair follicle called the bulge contains stem cells that can give rise to new hair and help heal skin wounds. Early research with mice in 2004 showed promise for identifying the genes that cause baldness and to identify drugs that can reverse the process.

Prognosis

The prognosis varies with the cause. It is generally much easier to lose hair than to regrow it. Even when it returns, it is often thin and less attractive than the original.

Resources

Periodicals

Cohen, Philip. "Stem Cells Generate Hair and Hope for the Bald." New Scientist (March 20, 2004): 17.

Lohr, Elizabeth. "Alopecia Nearly Epidemic Among Black Women." Clinical Psychiatry News (March 2004): 96.

Nielsen, Timothy A., and Martin Reichel. "Alopecia: Diagnosis and Management." American Family Physician.

Other

Androgenetic Alopecia.com. "How can minoxidil be used to treat baldness?" May1, 2001. http://androgenetic-alopecia.com/baldnesstreatments/minoxidil/002minoxidilbaldnessusee.shtml.

Mayo Clinic. "Alopecia" January 26, 2001. [cited May 1, 2001]. http://www.mayohealth.org.

WebMD Medical News. "Hair Today, Gone Tomorrow, Hair Again" 2000. [cited May 1, 2001]. http://my.webmd.com/content/article/1728.53923.

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alopecia /al·o·pe·cia/ (al?o-pe´shah) baldness; absence of hair from skin areas where it is normally present.alope´cic

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androgenetic alopecia  a progressive, diffuse, symmetric loss of scalp hair, believed due to a combination of genetic predisposition and increased response of hair follicles to androgens, in men beginning around age 30 with hair loss from the vertex and frontoparietal regions (male pattern a. or male pattern baldness), and in females beginning later with less severe hair loss in the frontocentral area of the scalp.

alopecia area´ta  hair loss, usually reversible, in sharply defined areas, usually involving the beard or scalp.

cicatricial alopecia  irreversible loss of hair associated with scarring, usually on the scalp.

male pattern alopecia  see androgenetic a.

alopecia tota´lis  loss of hair from the entire scalp.

traction alopecia  traumatic alopecia due to continuous or prolonged traction on the hair, as applied in certain styles of hair dressing or in the habit of twisting the hair.

alopecia universa´lis  loss of hair from the entire body.

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al·o·pe·cia (l-psh)

n.

Loss of hair; baldness.

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alo·pecic (-psk) adj.

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alopecia (aˈ·l·pēˑ·sh),

n Partial or total hair loss caused by a number of possible factors, including old age, drug reaction, endocrine disorder, skin disease, or cancer treatment.

Alopecia. areata.

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alopecia (al´pē´sh),

n the loss of hair. Baldness. Various types with varying causes.

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alopecia

deficiency of the hair or wool coat; may be caused by failure to grow or by loss after growth. There is a significant difference amongst those in which grown fibers are lost, between those in which stumps of fibers remain, and those in which the hair root has been shed from the follicle. See also hypotrichosis, alopecic.

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alopecia areata

noninflammatory hair loss in sharply defined areas. A rare condition seen in dogs, cats, horses and primates; the cause is unknown, but immune-mediated mechanisms are suspected.

bilaterally symmetric alopecia

a clinical feature associated with endocrine and metabolic causes of hair loss in dogs and cats, although other causes including self-trauma are sometimes responsible.

cicatricial alopecia, alopecia cicatrisata

irreversible loss of hair associated with scarring.

collar frictional alopecia

loss of hair around the neck occurs in some cats wearing collars. It is reversible when the collar is removed.

color dilution alopecia

color mutant alopecia (below).

color mutant alopecia

a clinical syndrome seen in dogs with blue or fawn coat color caused by the dilution gene at the D locus. Clinical signs include bacterial folliculitis, scaling and hair loss, mainly over the back and commencing within the first year or two of life. Hairs contain clumped melanin (macromelanosomes) with distortion and fracture of the shaft. Seen most often in Doberman pinschers but reported in a number of other breeds. Called also blue Doberman syndrome, fawn Irish setter syndrome. Seen also in many breeds of cattle, especially Simmental, Angus. Characterized by short, sparse, curly haircoats and wispy tail switch. Called also color dilution alopecia.

alopecia congenitalis

complete or partial absence of the hair at birth.

endocrine alopecia

hair loss caused by an endocrine abnormality that adversely affects hair growth. Usually characterized by symmetrical distribution and noninflammatory changes in the skin.

feline acquired symmetric alopecia

a bilaterally symmetric hair loss on the posterior abdomen, inner thighs, perineum and, less consistently, ventral thorax, flanks and forelegs of cats, most commonly neutered males. The skin is usually normal and nonpruritic. The cause is unknown; sex hormone deficiency was previously believed to be responsible, but abnormal thyroid function is also suspected. Some cases are in reality self-inflicted by excessive grooming or the cat's response to unrecognized pruritus. Called also feline endocrine alopecia.

inherited symmetrical alopecia

calves born with a normal haircoat lose their hair over bilaterally distributed specific areas of the skin. See also inherited congenital hypotrichosis.

alopecia medicamentosa

hair loss due to ingestion of a drug.

alopecia mucinosa

hair loss associated with mucinosis of the epidermis and hair follicles.

pattern alopecia

see pattern baldness.

periodic alopecia

a pinnal alopecia observed in miniature poodles. Regrowth usually occurs in 3 to 4 months.

pinnal alopecia

gradual loss of hair on the pinnae until there is total alopecia. Occurs mainly in Dachshunds and may have a hereditary basis.

pituitary alopecia

see growth hormone-responsive dermatitis.

post-clipping alopecia

a failure of hair to regrow, usually for a long period, after clipping. Seen particularly in Chow Chows, Samoyeds and Siberian huskies. The cause is unknown.

postvaccination alopecia and panniculitis

a focal area of hair loss occurring at the site of rabies vaccination; miniature poodles are predisposed.

progressive alopecia, congenital anemia and dyskeratosis

a condition seen in Hereford cattle; affected calves are born with sparse, short kinky or curly hair which is gradually lost. They are also anemic.

psychogenic alopecia

hair loss resulting from intensive self-trauma such as licking or biting and for which no cause can be found. Boredom is often considered a factor. See also acral lick dermatitis, idiopathic hyperesthesia syndrome.

seasonal flank alopecia

a cyclic follicular dysplasia which tends to occur seasonally, mainly in spring or fall. There is a nonpruritic hair loss and often hyperpigmentation of the skin in irregular, defined areas on the flanks and lateral thorax. Many cases regrow hair after 3 to 6 months, but recurrences at the corresponding time in following years is common. Boxers, Airedale terriers, English bulldogs, and Miniature schnauzers are predisposed breeds, but it has been reported in others. Called also cyclic follicular dysplasia.

symptomatic alopecia, alopecia symptomatica

loss of hair due to systemic or psychogenic causes, such as general ill health, infections of the skin, nervousness, a specific disease, or to stress. The hair may fall out in patches, or there may be diffuse loss of hair instead of complete baldness in one area.

traction alopecia

loss of hair due to traction, as occurs in dogs of breeds in which hair on the head is held by rubber bands or barrettes.

traumatic alopecia

that caused by self-trauma (licking, scratching, chewing or pulling); possible in any pruritic skin disease in any species, but particularly severe in cats. The area of hair loss corresponds to those areas most accessible to the form of self-trauma.

alopecia universalis

congenital absence of hair from the entire body. A characteristic of the Canadian hairless cat and Sphinx cat.