The many possible causes of hair loss

Everyone loses around 100 hairs from their head every day, but
serious hair loss isn’t a “one cause fits all” type of problem; many
factors contribute to hair loss, and we give you the full rundown
in Chapters 4 and 5. The most common causes of hair loss are
listed here.
 Genetics: Yes, you knew it all along: It’s Mom’s (or Dad’s) fault
that you have no hair. The overwhelming majority (up to 98
percent) of men with balding fall into the genetic category.
Female genetic balding occurs much less frequently, but up to
50 percent of women have hair loss related to their inherited
genes. (See Chapter 4 for more on genetics and hair loss.)
The good news is that only seven percent of men develop the
most advanced balding pattern (left with just a 3 inch wreath
of hair around the side and back of the head). If you’ve inher-
ited this pattern, it’s usually evident by the time you’re 30.
Genetic hair loss in men generally falls into one of several
distinct hair loss patterns identified under the Norwood class-
ification system (see Chapter 4). In balding men, the hair
around the sides of the head almost always retains a normal,
thick appearance. In women, genetic hair loss is different; for
one thing, it tends to occur as overall hair thinning (including
the sides of the head) rather than loss of hair on certain areas
of the head.
 Diseases: A number of diseases as well as hormonal influ-
ences, including thyroid disease and anemia, cause hair loss.
Autoimmune disease also can cause patchy hair loss. We
cover these causes in Chapter 5.
 Mechanical causes: Mechanical hair loss is caused by exter-
nal forces such as tight braiding, rubber banding, turbans,
or other hair torture devices that put stress and strain on
your hair.
 Stress: In some cases, stress can contribute to hair loss in
those who are genetically predisposed to it or can result in a
sudden loss of hair in a condition called telogen effluvium
(read all about it in Chapter 5).
 Medications: Many medicines, most notably anabolic
steroids, birth control pills, antidepressants, and tranquiliz-
ers, can cause hair loss. (See Chapter 5 for a complete list).