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Alopecia (Hair Loss)


By Wendy S. Levinbook, MD, Private Practice, Hartford Dermatology Associates

Hair loss, also called alopecia, can occur on any part of the body. Hair loss that occurs on the scalp is generally called baldness. Hair loss is often of great concern to people for cosmetic reasons, but it can also be a sign of a bodywide (systemic) disorder.

Hair grows in cycles. Each cycle consists of

  • A long growing phase (anagen)

  • A brief transitional phase (catagen)

  • A short resting phase (telogen)

At the end of the resting phase, the hair falls out, and the cycle begins again as a new hair starts growing in the follicle. Normally, about 50 to 100 scalp hairs reach the end of resting phase each day and fall out. When many more than 100 hairs/day go into resting phase, hair loss (telogen effluvium) may occur. A disruption of the growing phase that causes loss of hairs is called anagen effluvium.

Doctors sometimes classify hair loss as focal (confined to one part of the scalp) or diffuse (widespread). Hair loss may also be classified by whether or not scarring exists.


The most common cause of hair loss is

Other common causes of hair loss are

  • Certain systemic disorders, such as those that cause high fever, systemic lupus erythematosus (lupus), hormonal disorders, and nutritional deficiencies

  • Drugs, particularly chemotherapy

  • Fungal infections, such as ringworm of the scalp (tinea capitis)

  • Physical stresses, such as a high fever, surgery, a major illness, sudden weight loss, or pregnancy (which can lead to a telogen effluvium)

  • Injury (trauma)

Injury to the hair follicles has many causes including

  • Trichotillomania (habitual pulling out of normal hair related to psychologic stresses)

  • Traction alopecia (hair loss caused by continuous traction such as from braids, rollers, or ponytails)

  • Central centrifugal cicatricial alopecia (hair loss with scarring of the scalp, associated with the use of hot combs, chemical relaxers, and hair weaves)

  • Burns and radiation

  • Pressure-induced hair loss

Less common causes include primary hair shaft abnormalities (that is, the abnormality originates in the hair shaft), sarcoidosis, heavy metal poisoning, radiation therapy, and rare skin conditions.

Did You Know...

  • About 50 to 100 scalp hairs normally fall out each day.

Androgenetic alopecia

This form of alopecia may eventually affect up to 80% of white men by the age of 70 (male-pattern hair loss) and about half of all women (female-pattern hair loss). The hormone dihydrotestosterone plays a major role, along with heredity. The hair loss can begin at any age during or after puberty, even during adolescence (see Figure: Losing Hair).

In men, hair loss usually begins at the temples or on the top of the head toward the back. Some men lose only some hair and have only a receding hairline or a small bald spot in the back. Other men, especially when hair loss begins at a young age, lose all of the hair on the top of the head but retain hair on the sides and back of the scalp. This pattern is called male-pattern hair loss.

In women, hair loss occurs on the top of the head and is usually a thinning of the hair rather than a complete loss of hair. The hairline typically stays intact. This pattern is called female-pattern hair loss.

Losing Hair

In men, hair is usually first lost at the temples or on the top of the head toward the back. This pattern is called male-pattern hair loss.

In women, hair is usually first lost on the top of the head. Typically, the hair thins rather than is completely lost, and the hairline stays intact. This pattern is called female-pattern hair loss.

Alopecia areata

In alopecia areata, round, irregular patches of hair are suddenly lost. This disorder is believed to be caused by a malfunction of the body's immune system that causes the body to attack its own tissues (called an autoimmune reaction).

Central centrifugal cicatricial alopecia

Central centrifugal cicatricial alopecia is the most common cause of scarring alopecia in black people, typically occurring in women of African descent. Damage to the scalp, as from hot combs, chemical relaxers, or hair weaves in association with a predisposition to follicular damage due to abnormal hair follicles leads to progressive hair loss and scarring on the top and back of the scalp.

Cutaneous lupus erythematosus

In cutaneous lupus erythematosus, areas of hair may be lost. Hair loss may be permanent if the hair follicle is completely destroyed. Cutaneous lupus erythematosus can affect people who have or do not have systemic lupus erythematosus (SLE, or simply lupus), a disorder in which antibodies or cells produced by the body attack the body's own tissues (called an autoimmune disorder). Systemic lupus erythematosus affects various organs throughout the body. In cutaneous lupus erythematosus, hair tends to be lost in patches.

Hormone imbalance

If women have excessive amounts of male hormones, they can develop masculine characteristics (called virilization), such as a deepened voice, acne, and hair in locations more typical of male hair growth, such as the face and trunk (hirsutism). Virilization can also include scalp hair loss. The most common cause of virilization is polycystic ovary syndrome (PCOS). Rarely, a tumor can secrete male hormones, causing virilization, or virilization may develop in a female who is taking anabolic steroids to enhance athletic performance.

Drugs: Male-pattern or female-pattern baldness can occur when anabolic steroids are used. Chemotherapy drugs typically cause anagen effluvium. Other prescription drugs (for example, drugs used to treat high blood pressure, acne, thyroid disorders, seizures, or blood thinners) typically cause hair loss via telogen effluvium.

Nutritional disorders

Nutritional disorders are a less common cause of hair loss. Symptoms vary according to the specific nutritional disorder:

  • Excess vitamin A: Rash, scaly chapped lips, painful swelling of the limbs, sluggishness, loss of appetite, and weight loss

  • Iron deficiency: Anemia, easy exhaustion, and a decreased ability to exercise

  • Zinc deficiency: Rash, diarrhea, underdeveloped genitals, frequent infections, loss of appetite, and poor wound healing

Physical stresses

Stresses such as a high fever, surgery, a major illness, weight loss, or pregnancy can increase the number of hairs that go into the resting phase (causing telogen effluvium). Hair typically falls out a few months after the stress. This type of hair loss tends not to be permanent.

Psychologic stresses

These stresses can lead to the habitual twisting, teasing, or pulling out of normal hair (trichotillomania). The habit is most common among children but may occur in adults. The hair pulling may not be noticed for a long time, confusing doctors and parents, who may mistakenly think that a disorder such as alopecia areata or a fungal infection is causing the hair loss.

Ringworm of the scalp (tinea capitis)

Scalp ringworm is a fungal infection that is a common cause of patchy hair loss in children. The infection begins as a dry, scaly patch that gradually enlarges. Hairs may eventually break off, usually flush with the surface of the scalp, looking like black dots. Sometimes the hair breaks off above the surface of the scalp, leaving short stubs. Hair loss may be permanent, especially if the infection is left untreated.

Traction alopecia

This disorder is hair loss caused by tight braids, rollers, or ponytails that pull constantly on hair. Hair loss most often occurs at the hairline of the forehead and temples.


The following information can help people decide whether a doctor's evaluation is needed and help them know what to expect during the evaluation.

Warning signs

The following are of particular concern:

  • Signs of a bodywide disorder, including poisoning

  • In women, development of masculine characteristics (virilization), such as a deepened voice, hair in locations more typical of male hair growth (hirsutism), irregular menstrual periods, and acne

When to see the doctor

People who have hair loss and signs of a bodywide disorder should see a doctor promptly. Women who have developed masculine characteristics should call their doctor to discuss how soon they should be seen. Other people should see a doctor when possible, but an appointment is not urgent unless other symptoms develop.

What the doctor does

Doctors first ask questions about the person's symptoms and medical history and then do a physical examination. What doctors find during the history and physical examination often suggests a cause of the hair loss and the tests that may need to be done.

Doctors ask about the hair loss:

  • Whether hair loss began gradually or suddenly

  • How long it has been present

  • Whether hair loss is increasing

  • Whether hair is being lost over the entire head or in one specific area

They note other symptoms such as itching and scaling. They ask about hair care, including whether braids, rollers, and hair dryers are used and whether the hair is routinely pulled or twisted.

Doctors ask whether the person has been recently exposed to drugs, toxins, or radiation or has experienced significant stress (such as that resulting from surgery, chronic illness, fever or psychologic stress). The person is asked about other characteristics that may suggest a cause, including dramatic weight loss, dietary practices (including various restrictive diets), and obsessive-compulsive behavior. Current and recent drug use is reviewed. The person is asked whether any family member has had hair loss.

During the physical examination, doctors focus on the scalp, noting the distribution of hair loss, the presence and characteristics of any skin abnormalities, and the presence of any scarring. They measure the width of the central part at several points (see Figure: Losing Hair) and check for abnormalities of hair shafts.

Doctors evaluate hair loss elsewhere on the body (such as the eyebrows, eyelashes, arms, and legs). They look for rashes that may be associated with certain types of alopecia and for signs of virilization in women such as a deepened voice, hirsutism, an enlarged clitoris (the smaller female organ that corresponds to the penis), and acne. They also examine the thyroid gland.

Some Causes and Features of Hair Loss


Common Features*


Hair loss over the entire scalp

Male-pattern hair loss (androgenetic alopecia)

Often a family history

Sometimes a history of using anabolic steroids

A doctor's examination

Female-pattern hair loss (androgenetic alopecia)

Often a family history

Sometimes occurring during menopause

Sometimes in women with masculine characteristics (virilization), a history of using anabolic steroids such as dihydrotestosterone, polycystic ovary syndrome (PCOS), or a tumor that produces male hormones

A doctor's examination

Sometimes measurement of blood levels of the male hormones testosterone and dehydroepiandrosterone sulfate (DHEAS)

Drugs and toxins

A history of using a specific drug such as certain chemotherapy drugs, anticoagulants, retinoids, oral contraceptives, ACE inhibitors, beta-blockers, lithium, antithyroid drugs, anticonvulsants, or high doses of vitamin A or of being exposed to metals such as thallium and arsenic

A doctor's examination

Sometimes blood tests to check for exposure to toxins or heavy metals

Stress (psychologic or physical) causing telogen effluvium

Psychologic symptoms

Recent weight loss, surgery, severe illness with a fever, or delivery of a baby

A doctor's examination

Sometimes blood tests to check for anemia and iron deficiency and to evaluate thyroid function

Thyroid disorders

With hyperthyroidism (an overactive thyroid gland), difficulty tolerating heat, sweating, weight loss, bulging eyes, shakiness (tremor), restlessness, and an enlarged thyroid gland (goiter)

With hypothyroidism (an underactive thyroid gland), difficulty tolerating cold, weight gain, coarse and thick skin, and sluggishness

A doctor's examination

Blood tests that evaluate thyroid function

Nutritional disorders, such as vitamin A excess or a deficiency of iron or zinc

Symptoms of the specific nutritional disorder

A doctor's examination

Sometimes blood tests to check for nutritional disorders

Typically patchy hair loss, but sometimes loss of all scalp hair (alopecia totalis); sometimes loss of all body and scalp hair (alopecia universalis)

A doctor’s examination

Hair loss only in a specific area of the scalp

Alopecia areata

Round patches of hair loss with short broken hairs (resembling exclamation points) around the edges of the patches

Sometimes a burning sensation or itching

Sometimes loss of hair from the side and back edges of the scalp (ophiasis)

A doctor’s examination

Cutaneous lupus erythematosus

Scattered patches of hair loss

Sometimes a rash on the scalp that tends to be red, raised, and scaly

Sometimes areas of scarring

Sometimes itching

A doctor's examination

Blood tests to check for lupus

Biopsy of the scalp

Lichen planopilaris (lichen planus of the scalp)

Shiny, reddish-purplish, flat-topped bumps

Scattered patches of hair loss

Often areas of scarring

A doctor's examination

Biopsy of the scalp

Burns, injuries, or radiation (for example, from radiation therapy)

A history of burns, radiation therapy, or injury

Often scarring

A doctor's examination

Sometimes other tests to check for the cause

Tinea capitis (ringworm of the scalp)

Bald areas sometimes with small black dots (due to hair that has broken off at the scalp surface) or hairs broken just above the scalp surface

Round, scaly areas of skin, which can be red or inflamed

A doctor's examination

Examination of plucked hairs under a microscope and/or culture of plucked hairs

Sometimes a Wood light examination

Traction alopecia

Braids, rollers, or ponytails that are left in too long or pulled too tight

A doctor's examination

Trichotillomania (compulsive hair pulling)

Typically an asymmetric, bizarre, irregular hair loss pattern

Sometimes obsessive-compulsive behavior

Affects women 4 times more often than men

A doctor's examination

*Features include symptoms and results of the doctor's examination. Features mentioned are typical but not always present.

Rarely, biopsy of the scalp is done.


Testing is usually unnecessary if a cause is identified based on the doctor's examination. For example, male-pattern or female-pattern hair loss generally requires no testing. However, if hair loss occurs in a young man with no family history of hair loss, the doctor may question him about use of anabolic steroids and other drugs. Women who have significant hair loss and who have developed masculine characteristics are asked whether they use prescription or illegal drugs and undergo blood tests to measure levels of the hormones testosterone and dehydroepiandrosterone sulfate (DHEAS). If the doctor's examination detects signs of other hormonal abnormalities or other serious illness, blood tests to identify those disorders may be needed.

The pull test helps doctors evaluate hair loss. Doctors gently pull on a bunch of hairs (about 40) on at least 3 different areas of the scalp. Doctors then count the number of hairs that come out with each pull and examine them under a microscope to determine their phase of growth. If more than 4 to 6 hairs in the telogen phase come out with each pull, the pull test is positive, and the person most likely has telogen effluvium.

During the pluck test, doctors abruptly pull out about 50 individual hairs (“by the roots”). Doctors examine the roots and shafts of the plucked hairs under a microscope to assess the hair shaft and determine the phase of growth. These results help doctors tell whether the person has a telogen effluvium, a primary hair shaft abnormality, or some other problem.

Daily hair counts can be done to quantify hair loss when the pull test is negative and it is not clear whether hair loss is actually excessive. Hairs lost in the first morning combing or during washing are collected in clear plastic bags daily for 14 days. The number of hairs in each bag is then recorded. Loss of more than 100 hairs/day is abnormal except after shampooing, when up to 250 hairs may be lost. Hairs may be brought in by the person for examination under a microscope.

A biopsy of the scalp skin is done if the diagnosis is not clear after a doctor's examination and other tests. A biopsy helps determine whether hair follicles are normal and can help differentiate alopecia that causes scarring (by destroying the hair follicle) from alopecia that does not. If the hair follicles are abnormal, the biopsy may indicate possible causes.


  • Treatment of specific causes

  • Sometimes hair replacement methods

Specific causes of hair loss are treated when possible. For example, antifungal drugs are used to treat scalp ringworm. Drugs that are causing hair loss are switched or stopped. Hormonal disorders can be treated with drugs or surgery, depending on the cause. Iron or zinc supplements can be given if these minerals are deficient. Cutaneous lupus and lichen planopilaris can usually be treated with corticosteroids or other drugs applied to the scalp or taken by mouth.

Traction alopecia is treated by eliminating physical traction or stress to the scalp.

Scalp ringworm is treated with antifungal drugs taken by mouth.

Trichotillomania is difficult to treat, but behavioral modification, clomipramine, or a selective serotonin reuptake inhibitor (such as fluoxetine, fluvoxamine, paroxetine, sertraline, escitalopram, or citalopram) may be useful.

Hair loss due to physical stresses such as recent weight loss, surgery, a severe illness with a fever, or delivery of a baby (telogen effluvium) is not typically treated because it tends to resolve on its own. Applying minoxidil to the scalp may be helpful for some people.

Hair replacement methods can be tried if hair does not regrow on its own, including

  • Drugs to prevent further hair loss or grow new hair

  • Hair transplantation

  • Wigs


Male-pattern and female-pattern hair loss can sometimes be treated effectively with drugs.

Minoxidil may prevent further hair loss and increase hair growth when applied directly to the scalp twice a day. Hair regrowth can take 8 to 12 months and is noticeable in only about 30 to 40% of people. The most common side effects are skin irritation, such as itching and rash. An increase in hair on the face can also occur.

Finasteride works by blocking the effects of male hormones on the hair follicles and is taken by mouth daily. Finasteride is not used in women. In men, its effectiveness at stopping hair loss and stimulating hair growth is usually evident within 6 to 8 months of treatment and increases over time but can vary from person to person. Finasteride can decrease libido, increase breast size, and contribute to erectile dysfunction. Finasteride can also decrease prostate-specific antigen (PSA) levels. Men should discuss how finasteride can affect prostate cancer screening with their doctor before they begin treatment.

The most important effect of minoxidil or finasteride may be to prevent further hair loss. The effects last only as long as the drugs are taken.

Hormonal modulators, such as birth control pills (oral contraceptives) or spironolactone, may be useful in some women, especially those who have developed masculine characteristics.

Hair transplantation

Transplantation is a more permanent solution. In this procedure, hair follicles are removed from one part of the scalp and transplanted to the bald area. In this technique, only one or two hairs are transplanted at a time. Although this technique is more time-consuming, it does not require removal of large plugs of skin and allows the implants to be oriented in the same direction as the natural hair.

Another surgical option involves removing some bald parts of the scalp skin and stretching the parts that have hair over a wider area.


Wigs often offer the best treatment for temporary hair loss (for example, that caused by chemotherapy). People undergoing chemotherapy should consult a wig maker even before therapy begins so that an appropriate wig can be ready when needed. When hair regrows, it may be different in color and texture from the original hair.

Key Points

  • Male-pattern and female-pattern hair loss is the most common type of hair loss.

  • Doctors look for an underlying disorder in women with signs of virilization.

  • Microscopic hair examination or scalp biopsy may be required to determine the reason for the hair loss.

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