Excessive Hair Growth - Common Skin Conditions: Skin Health

Content provided by the Faculty of the Harvard Medical School

Excessive hair growth

Just as hormones influence hair loss, they can also cause an overgrowth of hair. This condition is called hypertrichosis. It's most common in women and often occurs around the time of menopause because of increased androgen levels. Hypertrichosis is characterized by excessive growth in locations that already have fine, light-colored hair, such as the upper lip or along the jaw line. It differs from hirsutism, which causes women to develop male hair growth patterns. While hypertrichosis is related to age and hormonal changes, hirsutism is caused by underlying endocrine disorders such as adrenal gland tumors or polycystic ovary syndrome. Regardless of the cause, excess hair growth can be embarrassing. A variety of solutions, including new laser treatments, are available.

Treating excessive hair growth

The most common, temporary solution is shaving the excess growth. Plucking, waxing, and depilatories also offer temporary solutions. Traditionally, the only permanent means of removing excess hair has been with electrolysis, which uses a shortwave electrical current to destroy the hair follicles. Electrolysis can be used safely on most parts of the body except the underarms, where there is an increased risk for bacterial infection, and the delicate skin under the eyebrows.

Physicians have discovered how to permanently destroy hair growth using lasers or intense light sources. Certain laser light frequencies are absorbed by the dark pigment in hair, causing selective thermal damage to or destruction of the hair follicle. A single treatment can destroy up to 30% of follicles in the area treated. Hairs that do grow back are thinner and softer. Three treatments may destroy about half of the follicles in the area treated.

One type of laser used for this purpose is the long-pulsed alexandrite laser, which, in its Q-switched version, is also used to eliminate brown pigmented areas. People with fair skin and dark hair are most likely to obtain the best results with laser hair removal, while the treatment is ineffective in people with blond, white, or gray hair. In order to work, the light has to be absorbed by pigment in and around the hair follicle. Light-colored hair has little or no pigment and therefore does not absorb laser light. For most people, laser hair removal is faster, safer, and more effective than electrolysis. The cost depends on the size of the area being treated and the number of treatments needed.

In addition to lasers, a different kind of light source, called intense pulsed light, is effective in removing hair. (For more information on different types of lasers and cosmetic laser procedures, see "Laser and other procedures.")

Last updated:	July 20, 2007