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Hair Loss

What Is Hair Loss?

Hair loss of any sort is called alopecia—be it normal male-pattern baldness (androgenic alopecia, or AGA) that commonly occurs as men age, or abnormal hair loss associated with certain diseases, hormonal disturbances, or treatments such as chemotherapy. There are two general types of alopecia: scarring and non-scarring. In scarring alopecia, the hair follicles that support the hair shaft are destroyed by an underlying condition, so that hair loss is irreversible. In non-scarring alopecia (which includes AGA and alopecia areata), the follicles are preserved, so that regrowth of lost hair remains a possibility. Alopecia has many causes, all of which may affect both sexes.

Who Gets Hair Loss?

Nearly two-thirds of men develop some form of balding, and at least two-thirds of women have some form of hair thinning.

By far the most common form of hair loss is androgenetic alopecia, usually called male and female pattern baldness. By age 50 half of all men of European origin will experience this kind of hair loss, which can begin as early as age 20. Some other genetic groups— Asians, some Africans and African Americans, and Native Americans—seldom or never get bald in this manner. Though the exact process that shuts down the hair follicles has yet to be explained, the male hormone dihydrotestosterone plays a role.

Female pattern baldness usually begins at about age 30, becomes noticeable around age 40, and may be even more noticeable after menopause. The pattern of female hair loss is usually an overall thinning—two hairs where five used to be—rather than a bald area on top of the head, though women may have a receding hairline, too. As in males, hair follicles simply shut down, with hormones playing some role in the process. Some cases of baldness in females may be due to iron deficiency or thyroid abnormalities. Male pattern baldness in a female could be a sign of excess androgen production, such as from ovarian or adrenal tumors, or a side effect of contraceptive pills.


  • AGA in men: hairline recession at the temples and thinning hair over the vertex; progressive merging of these areas.
  • AGA in women: thinning of hair on top of head with a widened partline; unlike male pattern hair loss, frontal hair margins almost always preserved.
  • Alopecia areata (a common type of autoimmune hair loss usually first appearing in children or young adults): coin-size areas of temporary, often recurring, hair loss on the head or elsewhere; rarely, total scalp hair or body hair loss.

Causes/Risk Factors

  • An inherited change that normally occurs with age (AGA).

  • Following childbirth, women may experience a several month-long period of increased hair shedding (telogen effluvium).

  • An autoimmune response (alopecia areata).

  • Bacterial or fungal infections (when severe, may cause scarring and permanent hair loss).

  • Cutaneous (skin) discoid lupus or scleroderma (scarring alopecia).

  • Chemotherapy drugs (diffuse hair loss with temporary complete baldness).

  • Other drugs including corticosteroids, testosterone, heparin, occasionally cholesterol-lowering drugs, and antithyroid agents (increased rate of hair shedding).

  • Malnutrition (especially inadequate protein intake), digestive malabsorption, anorexia nervosa, rapid weight loss, or chronic illness.

  • Rare congenital and developmental defects.

  • Chemical and physical agents, such as acids, bleach, burns, freezing, or radiation (including x-rays and radiotherapy for cancer).

  • Poisoning with toxic levels of arsenic, bismuth, boric acid, and vitamin A.

  • Self-induced baldness from unconscious plucking out of hair (known as trichotillomania).

What If You Do Nothing?

It’s impossible to prevent male and female pattern baldness, and in most people the baldness will almost always become more noticeable as they age. For hair loss caused by illness, medication, radiation therapy, or hormonal fluctuations, hair will usually grow back when the condition or treatment has ended.


  • Alopecia can usually be diagnosed by examination of the characteristic patterns of hair loss.

  • More extensive medical tests are warranted when a pathological condition is thought to cause hair loss.


  • Any underlying medical condition causing alopecia needs to be diagnosed and treated.

  • Treatment for AGA is not necessary, but you can take steps to help maintain your hair’s cosmetic appearance. Combing is less injurious to hair than brushing. If you must brush, do so when your hair is dry. Be sure to disentangle the hair from the brush. Avoid hairbrushes and combs that pull your hair.

  • Avoid bleaching, hot combs, excessive sun exposure, permanent waving, and straightening.

  • The topical medication minoxidil (Rogaine®) often slows the loss of hair and may lead to regrowth of some hair. Use of minoxidil means lifetime commitment. Any new hair may vanish if you discontinue treatment, and the drug has not been shown to inhibit hair loss.

  • Men may benefit from the prescription oral drug finasteride, which causes some hair growth in most users, though it is not effective for men over age 60 or for those who are completely bald. Like minoxidil, finasteride must be taken every day to sustain its benefit. (Because finasteride may cause birth defects, it is not prescribed for women).

  • Hair gels, permanent waves, wigs, hair weaves, hair transplants, or surgery to reposition existing portions of the scalp are other methods to consider.

  • Women whose hair loss is related to excess levels of androgen may benefit from treatment with drugs that slow production of androgen or block its action. These medications include spironolactone (Aldactone) and dexamethasone (Decadron).

  • Treatment for alopecia areata usually depends upon how severe the hair loss is and whether it involves only one or two patches or is more extensive. A combination of treatments is often the best approach.

  • Hair transplantation, which involves the doctor transplanting part of the scalp with full hair thickness to the bald patch, is expensive, time consuming, and sometimes painful. A very small percentage of patients suffer chronic head pain afterward. Potential complications include permanent scarring and chronic infection.

  • Scalp reduction involves reducing the size of the scalp. The doctor stretches the skin on the top of the head and cuts some of it away, thereby reducing the total area of bald skin. In a procedure known as a “flap,” the doctor stretches a piece of skin that has hair on it and folds it over the bald area. Scalp reduction is often combined with hair transplantation.


  • It’s impossible, at present, to prevent male and female pattern baldness.
  • Hair shaft breakage may be prevented by not over-processing hair with coloring agents or procedures such as permanent waving or straightening.

When To Call Your Doctor

Although it is normal to shed 50 to 100 hairs a day, consult your doctor or dermatologist if you notice persistent excess shedding, which may be a symptom of an underlying medical disorder. Also see your doctor if a scalp infection is suspected. Infection can lead to permanent hair loss.

Robert Hurd, M.D., American Board of Internal Medicine and Professor of Endocrinology and Health Care Ethics, Xavier University, Cincinnati, OH. Review provided by VeriMed Healthcare Network.