Your hair is a fairly accurate barometer of your health. Hair cells are some of the fastest growing in the body, and when your body is under stress or in crisis, hair cells can shut down in order to redirect energy elsewhere, to places where it is needed. The types of physical situations that can cause hair loss include hormonal changes, nutritional deficiencies, a variety of medications, surgery, and many medical conditions, in particular, thyroid disease.
Hair loss is actually fairly common. According to the American Academy of Dermatology, nearly half of all adults in the U.S. will experience thinning hair by age 40. But thyroid patients in particular may experience hair loss earlier and more quickly than usual.
Normally, hair grows about a half inch a month for about three years, and then it goes into a resting period.
One in ten hairs is in a resting period at any one time, and after about three months a new hair pushes the old one out. When more hairs go into resting period, or the conversion process speeds up, the balance becomes disrupted, and hair loss occurs.
Hormonally induced hair loss takes place when an enzyme starts to convert the hormone testosterone on the scalp to its less useful version, dihydrotestosterone, or DHT. DHT then attacks the hair follicle, and shrinks it, even making it disappear entirely. Hair becomes thinner and finer, and may stop growing entirely. This conversion of testosterone to DHT seems to be sped up in some patients with hyperthyroidism or hypothyroidism, and may be the cause of hair loss that continues for thyroid patients, despite what is considered sufficient thyroid treatment.
Some people actually complain that rapid hair loss is the worst symptom of their thyroid problem - the thinning hair, large amounts of hair falling out in the shower or sink, often accompanied by changes in the hair's texture, making it dry, coarse, or easily tangled. Interestingly, some people have actually written to tell me that their thyroid problem was initially "diagnosed" by a hairdresser, who noticed the change in their hair!
While thyroid disease frequently causes general hair loss from the hair on the head, a unique and characteristic symptom of hypothyroidism is loss of the hair on the outer edge of the eyebrows. General loss of body hair from areas other than the head can also be seen in thyroid disease.
If you have a thyroid condition, and are concerned about the amount of hair you are losing, here are some steps to take.
Get Evaluated by a Dermatologist.
Even if you are in the midst of dealing with a thyroid problem, it's still a good idea to see a dermatologist. A good dermatologist experienced in hair loss can do a complete workup in order to assess the various causes of hair loss, and run tests that may identify other autoimmune conditions besides thyroid that may cause hair loss. For a hair loss specialist, visit the American Hair Loss Council website at http://www.ahlc.org/members.htm, or contact the American Academy of Dermatology, who can provide a referral to a dermatologist in your area.
Make Sure It's Not Your Thyroid Drug
If you are taking levothyroxine (i.e., Synthroid, Levoxyl, Unithroid, Levothroid) as your thyroid hormone replacement, and still losing hair, you may need to take action. Prolonged or excessive hair loss IS a side effect of these drugs for some people. Note: Many doctors do NOT know this, even though it is a stated side effect in the Synthroid patient literature, for example, so don't be surprised if your doctor is not aware of this.