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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

• Male pattern baldness (androgenic alopecia) is considered normal in adult males. It is easily recognized by the distribution of hair loss over the top and front of the head and by the healthy condition of the scalp.
• Alopecia areata is a hair loss condition of unknown cause that can be patchy or extend to complete baldness.
• Fungal infections of the scalp usually cause patchy hair loss. The fungus, similar to the ones that cause athlete's foot and ringworm, often glows under ultraviolet light.
• Trichotillomania is the name of a mental disorder that causes a person to pull out his or her own hair.
• Complete hair loss is a common result of cancer chemotherapy, due to the toxicity of the drugs used.
• Systemic diseases often affect hair growth either selectively or by altering the skin of the scalp. One example is thyroid disorders. Hyperthyroidism (too much thyroid hormone) causes hair to become thin and fine. Hypothyroidism(too little thyroid hormone) thickens both hair and skin.
• Several autoimmune diseases (when protective cells begin to attack self cells within the body) affect the skin, notably lupus erythemematosus.
• In 2004, a report a the annual meeting of the American Academy of Dermatology said that alopecia was becoming nearly epidemic among black women as a result of some hairstyles that pull too tightly on the scalp and harsh chemical treatments that damage the hair shaft and follicles.

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.

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.

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.

For Your Information

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.

• Androgenetic Alopecia.com. "How can minoxidil be used to treat baldness?" May1, 2001.
• Mayo Clinic. "Alopecia" January 26, 2001. [cited May 1, 2001].
• WebMD Medical News. "Hair Today, Gone Tomorrow, Hair Again" 2000. [cited May 1, 2001].

This article was updated on 08-14-2006