The average scalp has approximately 100,000 hair follicles, from which 50 to 100 hairs are shed every day. This sounds like a lot but it's normal. Baldness, in any area or to any degree, occurs when the rate of shedding exceeds the rate of re-growth. This equation, while seemingly obvious, bears emphasizing because with any kind of alopecia (the medical term for hair loss) early diagnosis and treatment to maximize re-growth before the hair follicles become irrevocably damaged will be the key to success, if success is possible. But before we get into hair loss and the reasons for it, and how to reverse it or put it back in once it's gone, let's look at how healthy hair grows.
The normal growth cycle has three phases: the anagen or actual growing phase during which a hair strand grows about a centimeter (less than a half an inch) per month for approximately three or more years, followed by the catagen phase in which the growth of the hair stops. The hair then enters the telogen or resting phase that goes on for about three months. After this, the hair strand falls out and the growth stage starts again. That is, if some kind of alopecia doesn't rear its (potentially bare) head.
What Causes Baldness?
There are several kinds of alopecia, which can be permanent or temporary. Androgenetic alopecia or male pattern baldness is the most common. It has a strong hereditary component and affects about a third of men and women. In men with this condition, the hormone dihydrotestosterone (DHT), a potent natural derivative of testosterone, activates the gene for hair loss. Hair follicles then start to produce shorter and thinner hair, and eventually stop functioning entirely. Once this occurs, only surgical hair transplantation can re-grow hair in the bald area. In women, the relationship of hair loss to DHT is less clear, as less than 40 percent of women with androgenic alopecia actually have elevated androgens.
Temporary hair loss conditions include alopecia areata, thought to be an autoimmune disorder in which the body's immune system attacks hair follicles and disrupts normal hair formation, leading to patchy loss of hair. Although most patients with alopecia areata have no other associated abnormalities, some have other autoimmune disorders such as thyroid disease, vitiligo, lupus, rheumatoid arthritis and ulcerative colitis. Major life stress may cause a temporary thinning of hair (telogen effluvium), one of the most common causes of hair loss in women. This is due to a sudden shift of growing hairs from the anagen to the telogen stage, resulting in hair loss beginning about three months after a major illness, stress, delivery of a baby, a crash diet, thyroid disease or use of a new medication such as birth control pills. Chemotherapy drugs can also cause hair loss (anagen effluvium) because the chemicals literally poison hair follicles. Once therapy is completed, however, the hair cycles can be re-established.
Because there's no single cause for alopecia, many myths have emerged to explain it, along with a raft of specious cures. One claim made by certain shampoos is that clogged pores lead to hair loss, so these products "open the pores" of the hair follicles. No. Clogged pores lead to ingrown hair, not hair loss, so save your money. Another favorite is that poor circulation causes hair loss. Again, no. Even in areas of supposed poor circulation, hair will grow after transplantation. The glut of ineffective or downright fraudulent treatments is why I strongly urge anyone noticing any kind of unusual hair loss to seek the evaluation and advice of a physician as soon as possible.
Medications to Re-Grow Hair
Minoxidil, an over-the-counter medication sold as Rogaine, works by activating the hair follicle into its growth phase. In both sexes, it has been shown to be superior to placebo in causing minimal to moderate hair regrowth. The new hair is often thinner and shorter than the original hair.
Antiandrogen treatment with drugs such as spironolactone and flutamide is effective in some patients, but is not approved by the FDA for the treatment of hair loss. Also, these drugs pose a danger to a fetus if the mother ingests them because they will enter the fetal circulation and may cause ambiguous genitalia in male offspring.
Finasteride (Propecia) reduces the conversion of testosterone to its potent metabolite DHT. This is approved for use in men with male pattern baldness, but not in women because of the risk of causing genital abnormalities in male offspring. In addition to stimulating new hair growth, it often slows hair loss, so should be used relatively soon after hair loss becomes noticeable. These medications have to be used for a minimum of six months before concluding whether the drugs are effective or not.
Other treatments include corticosteroids, which may be injected into the scalp of individuals that have limited alopecia areata and often will lead to new hair growth. Anthralin is a tarry substance used to treat psoriasis and has had some success in patients with alopecia areata. There are also a number of creams, gels, pills, shampoos and other nostrums sold over the Internet or at health food stores that claim to enhance new hair growth, but generally there is no scientifically valid data behind those claims.
What About Surgery?
Patients for whom a physician has recommended surgical hair transplantation will be glad to know that the treatment has evolved from implanting unsubtle plugs to extremely acute micro- and mini-graftings that replace one to three hairs at a time, creating a natural looking hairline. Surgical options also include scalp reduction surgery, in which bald scalp is removed and hair-bearing scalp is stretched upward to replace it; scalp flap surgery that moves a "flap" of hair-bearing skin and underlying tissue from one area of the body to another (best for patients with only frontal baldness); and bald scalp excision, in which bald scalp is removed and hair-bearing scalp is transplanted later.
Needless to say, these treatments can be costly, time consuming, and produce a certain amount of discomfort during the healing process. If transplantation surgery is warranted, the same rules apply as when choosing a surgeon for any procedure (see my blog on plastic surgery). Research your surgeon's credentials thoroughly. Find out which hospitals he or she is affiliated with and where they have surgical privileges. Discuss your objectives; be fully educated about the procedure, the appropriate expectations and the potential side effects.
The toupee has also evolved, especially the attachment methods. The vacuum prosthesis is a silicon shell base with implanted hair. A clear co-polyester film is attached to the bottom of the shell, creating a strong vacuum seal that keeps the hairpiece securely in place. The transdermal membrane graft uses a polymer almost as thin as a contact lens as an attachment device. Also, for some individuals, weaves, which are external hair-bearing devices made of real or artificial hair that are attached directly to the scalp or to existing hair, may provide an excellent cosmetic result.
Although most scalp hair loss has a strong hereditary component and rarely reflects a serious medical condition, it can be psychologically devastating to the individual. Therefore, if you, a loved one or a friend is distraught over hair loss, it is important to seek out a physician who is knowledgeable about the topic (such as a dermatologist) and is also sympathetic to the emotional needs of those who suffer from excessive hair loss.
Follow Glenn D. Braunstein, M.D. on Twitter: www.twitter.com/CedarsSinai