Hair Loss (Alopecia)

Reviewed on 3/31/2022

What Is Hair Loss (Alopecia)?

Hair Loss
Normal hair thinning (resulting from follicular miniaturization) involving the temples, frontal hairline, and crown of the scalp, known as "pattern alopecia," occurs in almost everyone as they age.

The loss of hair (alopecia) is a natural phenomenon in all hair-bearing animals that normally occurs during the hair growth cycle. It is estimated that most individuals (assuming they have a full head of hair) lose about 100 scalp hairs over a 24-hour period. Hair loss can become a cosmetic problem when it occurs in the wrong place at the wrong time in the wrong individual. True hair loss should be distinguished from damage to the hair shaft, which may cause breakage close to the scalp. This sort of damage is often caused by exogenous chemicals used to alter the physical characteristics of the hair shaft (hair dye, etc.) or other forms of self-manipulation.

Physicians divide cosmetically significant hair loss into two categories.

  1. Scarring alopecia: This sort of irreversible hair loss is characterized by damage to the underlying skin which results in scarring that destroys the hair follicle and its potential for regeneration. A simple visual examination is usually sufficient to diagnose this problem, although occasionally a biopsy may be necessary. Certain skin diseases, as well as physical trauma, produce this sort of damage.
  2. Non-scarring alopecia: This potentially reversible type of hair loss is very common and can be due to many causes, including certain diseases, drugs, aging, diet, as well as a genetic predisposition for hair loss called androgenetic alopecia (common balding).

There are three cycles of hair growth: growing (80% of follicles), resting, and shedding. In human hair, each follicle cycles at its own individual rate as opposed to most animals, where these cycles change with the season, and all hairs are in the same part of the cycle at the same time. This is why animals grow a thicker coat in the fall and shed most in the spring and why human beings do not shed. Unlike most animals, in humans, each hair has its own pattern of growing, resting, and shedding.

  • Each person sheds hair and regrows hair every day.
  • When this balance is disturbed and more hairs are shed than are regrown, alopecia or hair loss results.

What Causes Hair Loss?

Common causes of hair loss

  • Pattern baldness, a non-scarring alopecia (androgenetic alopecia), is genetically determined. In afflicted postpubertal individuals, hair follicles in the center of the scalp and over the temple begin to miniaturize, producing small, fine hairs which are difficult to see. This process is due to the metabolism of testosterone by an enzyme in the hair follicle. Generally, hair follicles over the ears and around the posterior of the scalp do not possess this enzyme so a fringe of normal hair is maintained.
  • Female-pattern baldness is very similar to its male counterpart, it occurs after menopause, and often spares the frontal hairline. It usually involves an overall thinning of hair.
  • Telogen effluvium is a phenomenon that occurs mostly in females, especially post-pregnancy when there is an entirely, spontaneously reversible shedding of scalp hair.
  • Alopecia areata, a non-scarring alopecia, is thought to be an autoimmune disease and is characterized by distinct, localized, sharply marginated areas of hair loss. This characteristically spontaneously remits but occasionally can result in the loss of 100% of all body hair.
  • Medications such as allopurinol (Zyloprim), oral vitamin A analogs, chemotherapeutic drugs, and warfarin (Coumadin)
  • Poor nutrition and strict dieting and certain types of bariatric surgery
  • Uncommon causes of alopecia

What Symptoms and Signs May Accompany Hair Loss?

You May Shed More Hair Than You Think
All hair follicles, including the 100,000+ on the scalp, exhibit a growth cycle.
  • Most people notice hair loss when looking at themselves in a mirror or when it is brought to their attention by others.
  • You may also find many hairs on your pillow in the morning or in your hairbrush or comb.
  • A woman may notice a decrease in the size of her ponytail or the widening of her part.

When Should Someone Seek Medical Care for Hair Loss?

  • If you have hair loss, you may want to see a doctor to evaluate if there are any medical reasons for the hair loss and to evaluate if any therapies are available for you.
  • See your doctor if you are losing large amounts of hair every day and if you are not feeling well at the same time you are losing hair.
  • Most often hair loss occurs without other signs of illness.
  • If the following symptoms occur at the same time as hair loss, you may have a serious medical condition and you should see a doctor right away.

There is no reason to seek emergency medical care for hair loss.

How Do Healthcare Professionals Assess and Diagnose Hair Loss?

Physicians, generally dermatologists and occasionally endocrinologists, diagnose hair loss by performing a physical examination of the hair shaft and the underlying skin and the distribution of hair loss.

  • Charts with pictures of hair loss help to classify the amount and type of hair loss. These include the Hamilton and Ludwig classification charts.
    • Extra tests may be necessary if the diagnosis is uncertain, especially if you have symptoms besides hair loss.
    • A hair pull test can be performed to examine multiple hair shafts microscopically for thickness, length, structure, and growth phase and to determine if an abnormal number of hairs are falling out.
  • Different thicknesses and lengths occur in the most common type of hair loss, androgenic alopecia.
  • Skin problems leading to hair loss may be diagnosed by taking a sample of skin and hair from the affected area. A doctor looking at this under a microscope might find a specific cause.
  • If hair loss is severe or other signs of illness are present, your healthcare provider may order specific tests, including X-rays and blood tests.

What Is the Treatment for Hair Loss?

If hair loss is caused by an illness, treatment of the illness is the best treatment for hair loss. The decision to treat androgenetic alopecia depends upon its emotional effect on the patient's sense of well-being. Many different therapies to stop hair loss and regrow hair are promoted; you should discuss these options with your physician to establish their validity.

Treatment options for androgenetic alopecia include grooming techniques, wigs and hairpieces, medications, and surgery.

  • Styling hair to cover the areas with the most hair loss is effective for mild cases. Washing and styling the hair will not cause further hair loss.
  • For more severe hair loss, wigs and hairpieces can provide good results if you are willing to try them. Either of these options can be used in combination with medications or surgery if the results of styling or the hairpiece alone are not satisfying.

Are There Home Remedies for Hair Loss?

Treatment of this problem at home is difficult.

  • Decreasing the amount of pulling, tugging, and tension on the hair can prevent damage to the hair follicle and shaft.
  • Most people will need to see their doctor to determine if there is a medical problem causing hair loss and to consider if treatment is indicated.

A wide variety of nonprescription products and services are offered for hair loss.

You should discuss them with your physician before initiating any therapies, especially if you are on medications or have chronic illnesses.

What Is the Medical Treatment for Hair Loss?

Androgenetic alopecia

  • Finasteride (Propecia): a pill taken once daily that blocks the activity of an enzyme that metabolizes testosterone to a substance that inhibits hair growth. Any regrowth is not permanent. Finasteride is not used for the treatment of hair loss in women.
  • Minoxidil (Rogaine, Loniten): A medication you rub directly onto your scalp. This medication enlarges hairs and makes them grow for a longer period.
    • It works for both men and women some of the time.
    • It works best for balding at the top and back of the head and less well for the front area of the scalp.
    • Stopping this medication can result in loss of the hair that developed during its use.

Alopecia areata

Intralesional injection of steroids directly into the areas of involved skin can promote hair growth in treated areas.

When Is Surgery Appropriate for Hair Loss?

  • Hair transplant: A doctor takes plugs of hair from areas on your scalp where hair is thick and puts them on areas where your hair is thin.
    • This procedure, if performed by an expert, can produce a natural-appearing hairline but hair plugs placed by the neophyte can have a bothersome checkerboard appearance.
  • Follicular transplants, which move individual hairs units from one place to another, are replacing hair-plug transplants.
  • Scalp rotation: A doctor moves a piece of your scalp that has good hair growth to an area of poor growth. The procedure is effective in children, but adults do not respond well to this type of treatment.

Is Follow-up Necessary After Treatment of Hair Loss?

During treatment for hair loss, you can expect to return to the doctor periodically to determine the response to treatment and to monitor for side effects from the medications being used.

Is It Possible to Prevent Hair Loss?

Prevention can be accomplished only by early treatment. Sometimes what you think may be hair loss is actually just hair breakage from overuse of hair dryers, curling irons, dyes, and styling products.

What Is the Prognosis of Hair Loss?

The ability to stop hair loss most often depends on the underlying cause.

  • If taking a certain medication is the cause, stopping the medication should stop the hair loss.
  • The most common type of hair loss, androgenic alopecia, usually follows a pattern with hair thinning in the front of the scalp first and progressing on to involve the back and top of the head. This type tends to be progressive.
  • Finasteride helps stop hair loss in a majority of men, and minoxidil decreases hair loss in a significant percentage of men and women. It is important to realize that the beneficial effect of these medications is transient and if stopped the hair loss will continue.
    • The best prevention of hair loss is early treatment. Research has shown that minoxidil is most useful for people who have been losing hair for less than five years.
    • A doctor who can help determine if the medications are working and who can watch for side effects of the medications should follow up with people who are being treated with minoxidil or finasteride.

Hair Loss Pictures

This man demonstrates typical male-pattern baldness. Notice that the side and back regions are least affected.
This man demonstrates typical male-pattern baldness. Notice that the side and back regions are the least affected.
This is a typical view of male-pattern baldness from the back.
This is a typical view of male-pattern baldness from the back.
This man has mostly frontal balding. Early treatment is the only prevention of hair loss.
This man has mostly frontal balding. Early treatment is the only prevention of further hair loss.

Women's Hair Loss

Hair loss doesn't only happen to men. There are a variety of causes of hair loss in women, including hormone problems, childbirth, PCOS, alopecia areata, and ringworm, among others.

See pictures of other causes of women's hair loss, and learn about treatments for thinning hair.

Reviewed on 3/31/2022
Medically reviewed by Norman Levine, MD; American Board of Dermatology


Ahanogbe, Isabella, and Alde Carlo P. Gavino. "Evaluation and Management of the Hair Loss Patient in the Primary Care Setting." Prim Care Clin Offic Pract 2015: 1-21.

Rogers, Nicole E. "Medical Treatments for Male and Female Pattern Hair Loss." J Am Acad Dermatol 59.4 Oct. 2008: 547-566.

Stefanato, C.M. "Histopathology of Alopecia: A Clinicopathological Approach to Diagnosis." Histopathology 56.1 Jan. 2010: 24-38.