The reasons for hair loss are many. When hair loss begins suddenly, the cause
may be due to illness, diet, medication, or childbirth. If hair loss is gradual
and becomes more noticeable with each passing year, a person may have
hereditary hair loss. Certain hair care practices also can cause noticeable
hair loss.
The following summarizes some of the many causes for hair loss:
Hair Disorders
Hereditary thinning or baldness. Also called androgenetic alopecia, this is the
most common cause of hair loss. When men have hereditary hair loss, a receding
hairline is common as well as hair loss on top of the scalp. Women, on the
other hand, tend to keep their hairline and have visible thinning over the
front and top of the scalp. Very rarely, a man will experience the female
pattern of hereditary hair loss and a woman will show signs of male-pattern
hair loss. The reasons for this are unknown. About 80 million men and women in
the United States have hair loss due to hereditary thinning or baldness.
Alopecia areata. This autoimmune disease causes hair loss on the scalp and
elsewhere on the body. It develops in people of all ages and causes hair to
fall out in patches.
Cicatricial (scarring) alopecia. Developing in otherwise healthy men and women,
cicatricial alopecia is a rare condition that destroys a person s hair
follicles. Scar tissue forms where the follicles once were and re-growth is not
possible. Treatment attempts to stop the inflammation that destroys the hair
follicles.
Disease
Underlying medical condition. A warning sign for about 30 diseases, hair loss
often can be stopped or reversed with treatment for the underlying disease. Two
common underlying medical conditions that can cause hair loss are thyroid
disease and anemia caused by an iron deficiency.
Some cancer treatments. Radiation therapy and some chemotherapeutic medications
cause hair loss. While hair loss is usually temporary, it can be the most
traumatic part of therapy.
Ringworm of the scalp. Without effective treatment, this contagious fungal
infection, which is most common in children, can cause balding and scaling on
the scalp.
Trichotillomania. This impulse control disorder causes people to repeatedly
pull out their own hair. Aside from a constant urge to pull out the hair on the
scalp, sufferers often say they feel compelled to pull out their eyelashes,
nose hairs, eyebrows, and other hairs on their bodies.
Stress and Hormones
Physical stress. Significant hair loss can occur after a major surgery, high
fever, severe infection, or even the flu.
Hormones fluctuate. A dramatic change in hormone levels can cause hair loss
especially in women. Hair loss is common during menopause and after childbirth
due to falling estrogen levels. When hair loss is caused by falling estrogen
levels, the loss is usually temporary and hair re-growth occurs with time. If a
woman is 40 years of age or older, she should not expect to see the hair of her
youth with re-growth.
Diet
Weight loss. Even people losing weight in a physician-monitored program can
experience some hair loss 3 to 6 months after losing more than 15 pounds. This
hair loss is common, and hair growth does return to normal.
Vitamin A excess. Getting too much vitamin A through vitamin supplements or
medications can lead to hair loss. Once the body no longer has an excess of
vitamin A, normal hair growth resumes.
Protein intake too low. When the body does not get enough protein, it conserves
the protein it does get by shifting hair growth into the resting phase. Within
2 to 3 months, the person usually sees visible hair loss. This can be reversed
and prevented by eating enough protein. Meats, eggs, and fish are good sources.
Vegetarians can increase their protein intake by adding nuts, seeds, and beans
to their diet.
Iron intake too low. Consuming too little iron can lead to hair loss. Good
vegetarian sources of iron are iron-fortified cereals, soybeans, pumpkin seeds,
white beans, lentils, and spinach. Clams, oysters, and organ meats top the list
of good animal sources of iron.
Eating disorder. An eating disorder such as anorexia or bulimia can lead to
hair loss.
Medication
Prescription medications that can cause hair loss include:
Blood thinners
High-dose vitamin A
Medicines that treat arthritis, depression, gout, heart problems, and high
blood pressure
Birth control pills. Some women taking or discontinuing birth control pills
experience hair loss. This usually occurs in women with an inherited tendency
toward hair thinning.
Hair Care Practices
Hair cosmetics. Frequent bleaching or permanents can cause the hair to break.
Regular or improper use of dyes, gels, relaxers, and sprays also can cause hair
breakage. Dermatologists recommend limiting use of these hair cosmetics to
reduce hair breakage.
Blow dryers, flat irons, and similar devices. Frequent use of a blow dryer
tends to damage hair. The high heat from a blow dryer can boil the water in the
hair shaft leaving the hair brittle and prone to breakage. Allowing the hair to
air dry and styling it only when dry will lessen this risk. Dermatologists also
recommend limiting the use of flat irons, which straighten hair by using high
heat, and other devices such as curling irons.
Hairpins, clips, and rubber bands. When used to hold hair tightly, hairpins,
clips, and rubber bands can break hair. When selecting hairpins, dermatologists
recommend choosing one with a smooth, ball-tipped surface. Hair clips should
have spongy rubber padding where they make contact with the hair. To minimize
hair breakage, use loosely fitting clips and wear them in different areas of
the scalp so that hair breakage is not localized in a specific area. Rather
than using rubber bands for ponytails, try fabric scrunchies, which loosely
hold the hair.
Certain hairstyles. Years of wearing hair in a style that pulls on the hair
such as a ponytail, cornrows, or braids can cause a type of hair loss known as
traction alopecia.
Too much or vigorous grooming. Too much shampooing, combing, or brushing (100
strokes or more a day) or doing any of these too vigorously can cause hair
breakage. When hair breakage occurs, the hair appears shaggy or too thin.
Dermatologists also caution against vigorously rubbing wet hair with a towel to
dry it or combing wet hair. These also can cause hair breakage because wet hair
is more elastic and more vulnerable to breakage than dry hair.
Dermatologists Can Get to the Root of Hair Loss
With so many causes, it can take a bit of detective work to uncover the reason
for hair loss. Sometimes, more than one cause is responsible. And as we age,
one cause may follow another.
To diagnose the cause of hair loss, a dermatologist usually begins by obtaining
a detailed medical history. The patient is asked about medications taken,
allergies, family history, and diet. Women are asked about their menstruation,
pregnancy, and menopause. The dermatologist also performs a detailed inspection
of the hair and scalp and looks at the way the hair is distributed over the
rest of the body. While examining the hair and scalp, the dermatologist will
examine the pattern of hair loss and look for signs of illness, including any
indication of a scalp infection. Sometimes a hair pull, blood test, or scalp
biopsy is necessary to make the diagnosis.
Once the cause (or causes) is known, treatment or preventive measures can
begin. It is important to realize that when it comes to hair loss, there is no
quick fix. But dermatologists do have the knowledge and resources to halt hair
loss and generate new growth for many patients.