hair loss conditions go by the name "effluvium,"
which means an outflow. Effluviums characteristically
affect different phases of the hair growth cycle.
Hair follicles on the scalp do not continuously
produce hair. They cycle through a growth stage
that can last two or more years, then regress
to a resting stage for up to two months before
starting to grow a new hair fiber again. At
any time on a healthy human scalp, about 80%
to 90% of the hair follicles are growing hair.
These active follicles are in what is called
the anagen phase. That leaves up to 10% to 20%
percent of scalp hair follicles in a resting
state called telogen, when they don't produce
any hair fiber.
Telogen effluvium (TE) is probably the second
most common form of hair loss dermatologists
see. It is a poorly defined condition; very
little research has been done to understand
TE. In essence though, TE happens when there
is a change in the number of hair follicles
growing hair. If the number of hair follicles
producing hair drops significantly for any reason
during the resting, or telogen phase, there
will be a significant increase in dormant, telogen
stage hair follicles. The result is shedding,
or TE hair loss.
TE appears as a diffuse thinning of hair on
the scalp, which may not be even all over. It
can be a bit more severe in some areas of the
scalp than others. Most often, the hair on top
of the scalp thins more than it does at the
sides and back of the scalp. There is usually
no hair line recession, except in a few rare
The shed hairs are typically telogen hairs,
which can be recognized by a small bulb of keratin
on the root end. Whether the keratinized lump
is pigmented or unpigmented makes no difference;
the hair fibers are still typical telogen hairs.
People with TE never completely lose all their
scalp hair, but the hair can be noticeably thin
in severe cases. While TE is often limited to
the scalp, in more serious cases TE can affect
other areas, like the eyebrows or pubic region.
Whatever form of hair loss TE takes, it is fully
reversible. The hair follicles are not permanently
or irreversibly affected; there are just more
hair follicles in a resting state than there
should normally be.
There are three basic ways TE can develop.
1. There might be an environmental insult that
"shocks" the growing hair follicles
so much that they decide to go into a resting
state for a while. This results in an increase
in hair shedding and a diffuse thinning of hair
on the scalp. This form of TE can develop rapidly
and may be noticeable one or two months after
receiving the shock. If the trigger is short
lived, then the hair follicles will return to
their growing state and start producing new
hair fibers pretty quickly. This form of TE
usually lasts less than six months and the affected
individual has a normal scalp hair density again
within a year.
2. The second form of TE develops more slowly
and persists longer. The hair follicles may
not all suddenly shed their hair fibers and
enter a resting telogen state. Rather, the follicles
may enter a resting state as they normally would,
but instead of returning to a new anagen hair
growing state after a month or two, they stay
in their telogen state for a prolonged period
This results in a gradual accumulation of hair
follicles in a telogen state and progressively
fewer and fewer anagen hair follicles are left
growing hair. In this form of TE, there may
not be much noticeable hair shedding, but there
will be a slow thinning of the scalp hair. This
form of TE is more likely to occur in response
to a persistent trigger factor.
3. In a third type of TE, the hair follicles
do not stay in a resting state but rather cycle
through truncated growth cycles. When this happens,
the individual experiences thin scalp hair and
persistent shedding of short, thin hair fibers.
Causes of Telogen Effluvium: Stress
What are the trigger factors for TE? The short
answer is many and varied. Classic short-term
TE often happens to women soon after giving
birth. Called postpartum alopecia, the sudden
change in hormone levels at birth is such a
shock to the hair follicles that they shut down
for a while. There may be some significant hair
shedding, but most women regrow their hair quickly.
Similarly, vaccinations, crash dieting, physical
trauma such as being in a car crash, and having
surgery can sometimes be a shock to the system
and a proportion of scalp hair follicles go
into hibernation. As the environmental insult
passes and the body recovers, the TE subsides
and there is new hair growth.
Some drugs may also induce TE, especially antidepressants.
Often a switch to a different drug resolves
More persistent insults can result in more persistent
TE. For example, a chronic illness may lead
to TE. Arguably, the two most common problems
are chronic stress and diet deficiency. Many
dermatologists believe chronic stress can gradually
exert a negative effect on hair growth and lead
to persistent TE. Research with animal models
has provided evidence to back up this claim.
There does indeed seem to be a link between
stress, a change in hair follicle biochemistry,
and more hair follicles entering a telogen resting
Whether dietary problems are causing TE in North
America is hotly argued among dermatologists.
A lack of a mineral, vitamin, or essential amino
acid can certainly cause TE, such as with people
in third world countries where diets can be
completely deficient in one or more nutrients.
Animal experiments also provide supporting evidence.
In first world countries the average diet is
rarely completely deficient in a particular
vitamin or mineral. However, some dermatologists
claim that with a reduction in red meat intake
and a preference for vegetarian diets, some
individuals are not getting a balanced intake
of all the nutrients required for good hair
and overall body growth. In particular, there
are claims that women may be deficient in their
iron intake. Why women specifically? Because
women lose iron at regular intervals as a result
Some dermatologists believe that as we now eat
less red meat, a key source of iron, some people
are not eating enough iron and TE is the result.
Other potential deficiencies of the modern North
American diet -- such as a lack of zinc, amino
acid L-lysine, or vitamins B6 and B12 -- have
also been suggested to contribute to TE.
When dietary deficiencies are suspected, supplements
may be taken. However, supplements themselves
can cause problems. Our bodies can only process
so much iron each day. At high doses, iron is
toxic and this can itself cause hair loss. At
really high doses, iron supplements will cause
death. Vitamin A supplements can also cause
a TE reaction in some individuals, as excessive
vitamin A can also be toxic.
TE can occur on its own or as part of another
disease. The early stages of androgenetic alopecia
(male or female pattern baldness, AGA for short)
are effectively TE. Early AGA is characterized
by an increase in resting telogen hair follicles.
Someone in the early stages of AGA may have
up to 40% of their scalp hair follicles in telogen.
TE can also be a symptom of other conditions,
such as inflammatory conditions like alopecia
areata. Hair follicles are particularly sensitive
to thyroid hormones and about one third of individuals
with a thyroid disorder have TE. Exposure to
toxins can also cause TE as one of many symptoms.
Treatments for Telogen Effluvium
How TE is treated depends on what has activated
it. For short-term TE that can be linked to
a trigger like surgery, the best response is
to sit tight and wait for the follicles to recover
of their own accord.
For persistent TE, if the causal factor can
be isolated, then the best method is to remove
it. For example, if stress is the problem, stress
reduction is the long-term answer. If a dietary
deficiency appears on a blood test, then supplements
can work. A deficiency in thyroid hormones can
be treated with hormone supplements.
However, often a specific causal factor cannot
be identified. If this is the case, there are
few treatment options. Most dermatologists resort
to prescribing minoxidil, a direct hair growth
stimulator. Minoxidil can work well for some
individuals with TE, but if the underlying cause
is still present, then minoxidil must be continued
to block redevelopment of TE. With removal of
the trigger, minoxidil use can be stopped.
Before leaving the subject of TE, here are a
few words about natural hair shedding. Everyone
sheds hair and you may see more hair shed at
certain times of the year. Studies show that
humans, at least in Northern Europe away from
the equator, shed more hair in the fall and
to a lesser extent in the spring.
This temporary increase in the number of telogen
hair follicles and shed hair is probably due
to changes in hormones in response to changes
in daylight exposure. Studies in mink and other
mammals show that daylight exposure significantly
alters prolactin levels and that prolactin has
a significant effect on molting. As with mink
and other mammals, humans probably have much
the same molting response. Such hair loss should
Anagen effluvium is a diffuse hair loss like
telogen effluvium, but it develops much more
quickly and can cause individuals to lose all
their hair. Anagen effluvium is most frequently
seen in people taking cytostatic drugs for cancer
or those who have ingested toxic products like
Substances of this type inhibit rapid cell proliferation.
This is a desirable factor if you are trying
to block the development of a cancer, but the
cells of hair follicles are some of the most
rapidly proliferating, noncancerous cells the
body has. Hair fiber from scalp hair follicles
grows at up to 0.4mm a day and that rate of
growth requires a lot of cell proliferation.
Cytostatic cancer drugs and various toxins and
poisons inhibit rapid cell growth, including
the proliferation of cells in the hair follicles.
The result is a sudden shut down of hair fiber
The onset of anagen effluvium is very rapid.
Some individuals who start taking anti-cancer
drugs can literally pull their hair out in clumps
within the first two weeks. Because these drugs
act so quickly and are so potent, the hair follicles
have no time to enter into a telogen resting
state, as with telogen effluvium, a response
to a more moderate environmental challenge.
Instead, in anagen effluvium the hair follicles
enter a state of suspended animation, frozen
in time. The hair fibers fall out quickly, but
instead of looking like typical telogen hairs
with little bulbs of keratin on the root end,
the hairs that fall out are mostly dystrophic
anagen hairs with a tapered or sometimes feathered
With cytostatic anti-cancer drugs, the degree
of hair loss varies from person to person. Some
people may have a mixture of anagen effluvium
and telogen effluvium and have more limited
Some cancer treatment centers try to block the
hair loss using a cold therapy. More popular
in Europe than North America, cold therapy involves
covering the scalp with ice packs or using a
special hood filled with cold water while the
anti-cancer drugs are given. The cold sends
the hair follicles into suspended animation
prior to contact with the drug. This stops the
hair follicle cells from taking up the drug
and being damaged by it. The result is much
less drug-induced hair loss. However, doctors
worry that any cancer cells in the skin may
also avoid the anti-cancer drugs if cold therapy
is given during drug treatment.
Some experimental drugs to block drug induced
hair loss are under development, but the same
fear applies. The treatments to stop hair loss
may also protect any cancer cells in the skin.
While, the development of anagen effluvium is
rapid, the recovery is also equally rapid. Because
the follicles are just frozen in time, they
are ready to grow once the factor causing the
anagen effluvium has been removed.
On completion of an anti-cancer drug treatment
course, a person may start to see new hair growth
within a month. The hair follicles are not destroyed,
so there should be a normal hair growth density.
However, some people notice a change in the
nature of the hair fiber produced. Some people
find their hair changes from straight to curly
or vice versa, or sometimes there is a change
in hair color. These changes may be permanent.