Women and Hair Loss: The Causes

Last Editorial Review: 5/4/2005

Today more women than ever are experiencing hair loss -- and the causes may be quite different that what causes balding in men.

WebMD Feature

Reviewed By Charlotte Grayson

From Lady Godiva to the Breck Girl, Farah Fawcett to Jennifer Aniston, there is no question that, at least for women, hair is often a defining point in personal style. That's one reason why so many women panic at even the thought of losing a few hairs down the drain with each shampoo.

Those fears are not unfounded, as each year more women are forced to come to grips with the possibility of serious hair loss. According to the American Academy of Dermatology, it's a growing problem, affecting some 30 million women in the United States -- with some forms of loss occurring at earlier ages, and being seen in increasing numbers.

"I have seen women as young as 15 or 16 develop hair loss problems -- it's not common, but it's also not that rare," says Ted Daly, MD, a dermatologist from Nassau University Medical Center on Long Island, who specializes in the treatment of female hair loss.

But what exactly causes a woman to lose her hair? To understand that, it's important to know a little something about how hair grows.

Growth Cycle Interrupted

Experts say our tresses usually grow at the rate of about one-half inch per month -- with each hair having a growth phase of two to six years. At that point the hair "rests" for a period of time, then falls out -- and the follicle from which it sprang soon starts growing a new strand. And so the cycle continues, usually well into our senior years.

In some folks, however -- those with a genetic predisposition to hair loss -- a group of hormones called androgens interferes with this natural process. According to dermatologist Michael Reed, MD, androgen hormones include testosterone, androsteinedione, and dihydrotestosterone (DHT) -- all of which are made in men's bodies in large amounts, and in women's bodies in small amounts.

In those who are genetically susceptible, when testosterone comes in contact with enzymes residing in the hair cell, it is converted into the more potent androgen DHT, which then binds with receptors deep within the hair follicle.

"Over time, an excess build-up [of DHT] in the follicle causes it to begin shrinking, which in turn alters the natural resting and growth phases of the hair," says Reed, clinical associate professor of dermatology at NYU Medical Center, and a specialist in female hair loss. Some of the follicles eventually die, while others are rendered incapable of producing or maintaining healthy hair growth. The end result, says Reed, is hair loss -- and a condition that is medically known as androgenic alopecia.

For many decades, doctors believed that androgenic alopecia was the primary cause of balding in both men and women. Today they know this is not true -- at least where women are concerned.

Female, Male Balding Not the Same Pattern

"We don't even like to use the term 'androgenic alopecia' in women anymore -- instead we call it female pattern hair loss -- a broader term that encompasses many possible causes, some of which are likely to be directly linked to an excess of testosterone, and some of which are not," Daly tells WebMD.

Indeed, he says that although the science of female balding is still largely misunderstood, there is evidence that many other types of enzymes, as well as hormone receptors and blockers, may be at work in women.

One clue that there is a true difference between male and female balding is the pattern in which the hair loss occurs.

"Female pattern balding goes around the whole top of the head -- it's diffuse -- whereas men lose it on the temple, the crown, the bald spot in the back," says Daly. Not coincidentally, the hormone and enzyme receptor sites are also different in varying areas of the scalp -- another reason doctors now believe the loss patterns are caused by different precipitating factors.

Another important difference: While balding in men is almost always the result a genetic predisposition coupled with age, in women, it can happen at any time. In addition, underlying medical conditions can also be the cause of hair loss -- even when true androgenic alopecia is the diagnosis.

Medical Causes Common

"Often these women are also suffering with polycystic ovary syndrome, [a common hormonal problem in women], and sometimes their hair loss is the only obvious sign," says Ricardo Azziz, MD, director of the Center for Androgen-Related Disorders at the Cedars Sinai Medical Center in Los Angeles.

In addition, Daly reports that certain types of autoimmune disorders result in a slightly different and often less dramatic hair loss problem known as alopecia areata -- an inflammatory condition that causes hair to come out in clumps or patches.

Still others can develop a temporary hair shedding problem known as telogen effluvium -- a change in the natural hair growth system that often follows childbirth, crash dieting, surgery, or a traumatic emotional event.

Azizz adds that thyroid disorders, anemia, even chronic illness or the use of certain medications can also cause hair loss in women that is often undiagnosed.

For these reasons, specialists say it's vital for all women to get at the "root" of their hair loss before seeking treatment.

"The No. 1 rule of treating hair loss in women is getting the correct diagnosis -- if there is an underlying physical problem it has to be corrected first," says Reed. Often, he says, that can preclude the need for additional hair loss treatment. As such, he advises women to see a doctor who specializes in female pattern balding and make certain to be checked for possible underlying medical conditions via blood tests, or if need be, a scalp biopsy.

"Often the diagnosis is made by excluding what problem isn't there -- but it's still essential to do the complete workup," says Daly.


Your Hair and Scalp Can Say a Lot About Your Health See Slideshow

Reviewed by Charlotte E. Grayson, MD.

Published December 2003.

SOURCES: Ted Daly, MD, Garden City Dermatology and Nassau Community Medical Center, East Meadow, New York; Michael Reed, MD, professor, dermatology, NYU School of Medicine, New York City; Ricardo Azizz, MD, director, Center for Androgen -Related Disorders at the Cedars Sinai Medical Center in Los Angeles,; Nature, April 1999; Journal of The American Academy of Dermatology, November, 2003.

©1996-2005 WebMD Inc. All rights reserved.

Health Solutions From Our Sponsors