The loss of some hairs–about 100 a day–is normal, part of the natural process of growth and replacement. At any given time, about 10 percent of hairs on the scalp are in a resting (telogen) phase in preparation for being shed. A new hair then begins to grow in the same hair follicle. When hair is shed faster than it is replaced, the result is thinning of the hair or balding. Excessive hair loss, partial or total, is known as alopecia. And it comes in many forms–some of which are temporary and nearly all of which are treatable.
The male-type baldness that is most common typically occurs in certain patterns–a receding M-shaped hairline, a bald patch at the crown or a completely bald top with a horseshoe ring around the sides. This type of hair loss is primarily determined by genetics and the male hormone dihydrotestosterone. In response to dihydrotestosterone, some hair follicles shrink or become miniaturized, producing progressively shorter, finer hairs. Known as androgenetic alopecia, this kind of progressive hair loss can begin as early as age 12 and noticeable balding by age 30 in one-quarter of all men.
Women also suffer from androgenetic alopecia, although with a different pattern–generally without a receding hairline or completely bald areas. A woman may notice general thinning on top with a more exaggerated part line, which can be masked through hair styling. Women with androgenetic hair loss do not necessarily have higher levels of male hormone but rather more androgen receptors in hair follicles. If hair loss occurs in a typical male pattern along with signs of hirsutism, such as facial hair, a hormonal imbalance may be involved. Androgenetic baldness is usually associated with males, because their hair loss typically occurs earlier in life and becomes more noticeable, but this condition eventually affects about half of all men and women.
Similar appearing diffuse hair loss can be a result of telogen effluvium–a condition in which the normal growth cycle of hairs becomes abnormally shortened, causing a predominance of hairs in the telogen or resting phase preparing to be shed. Telogen effluvium is a temporary condition, usually caused by stress, either emotional or physical, or abnormalities of the thyroid, parathyroid or pituitary glands. Identifying and treating the underlying cause can reverse it.
The patchy hair loss that your Aunt Marjory is suffering from is more than likely alopecia areata, an autoimmune disorder that affects about two percent of Americans, both men and women. Although it can occur at any age, this type of hair loss is actually more common in children and young adults, usually causing a great deal of distress. There’s usually no clear reason why the immune system starts to attack hair follicles, and the problem often goes away on its own, usually to recur later. In milder forms, no treatment may be necessary, but it’s still a good idea to see your family doctor or a dermatologist. In some more severe cases, the patient may lose every hair on the head or even every hair on the body. Treatment may include use of corticosteroids–taken orally, rubbed on the skin or injected into the scalp. Anthralin cream, a psoriasis medication, may also be prescribed.
Some persons have patchy hair because they can’t stop pulling it out. Trichotillomania is a compulsive hair pulling behavior that the individual may try to hide or, in some cases, may not even be aware of. Sometimes a response to stress, this disorder usually begins in children between ages 8-12. Treatment is difficult, usually requiring counseling, behavioral therapy and antidepressant medications. Damage to the scalp should also be repaired.
Traction alopecia refers to hair loss caused by hairstyles such as ponytails or cornrows that put excessive pressure on hair follicles. With both trichotillomania and traction alopecia, it’s important to stop the damage before scarring of hair follicles occurs.
Any disorder or infection that causes scarring of the scalp can cause irreversible hair loss. Brush rollers, curling irons and repeated use of certain chemicals on the hair or scalp, can also cause traumatic damage.
What can you do?
In addition to treating the underlying cause, most types of hair loss can be reversed to some extent with minoxidil (Rogaine), available over-the-counter in a topical solutions to apply to the scalp. Minoxidil revitalizes and increases the size of hair follicles that are dwindling in size, creating increased density in a certain percentage of persons. It will not work, however, on areas that are totally bald, and you have to keep using the drug to maintain the effect. If you stop using minoxodil after 10 years, you will revert to what you would have looked like had you never taken it. Minoxodil should not be used on areas of the scalp that are inflamed, infected or irritated. Patients with known cardiac disease should avoid the product, and women should use the two percent rather than the five percent solution.
The other treatment for baldness, finasteride, slows hair loss and increases hair growth by inhibiting the conversion of testosterone to dihydrotestosterone. An oral prescription medication, it is not approved for females. For a pregnant woman, even handling the drug can affect the genitals of a developing fetus. Usually, there are no adverse effects in males but the drug can affect libido and erectile function.
It’s too easy to dismiss thinning, receding or patchy hair as a cosmetic problem. Even though only about five percent of cases are caused by illness, hair loss can have a damaging effect on image and self-confidence in social relationships.
Casey M. Valiente, PharmD
