The hormone imbalance known as hypothyroidism is a common cause of abnormal eyebrow thinning, especially in women; roughly 27 million Americans suffer from thyroid disease, and about 80 percent of them are women. Thinning eyebrows appear as a symptom of both hypothyroidism (underactive thyroid production) and hyperthyroidism (overactive thyroid production), alongside issues such as excessive fatigue, difficulty losing weight and constantly feeling cold. If your brows appear particularly thin around the edges, visit your doctor for a thyroid screening, which should include thorough blood work. With prescription medication, your eyebrows should fill back in over the ensuing months.
If, however, you aren’t so sure that any of the causes listed above are a problem for you, then a good place to start may be to talk with your healthcare provider about testing. It is important to learn the root cause – especially if dealing with infertility – because that which is causing hair thinning and shedding may also be contributing to your inability to conceive.
Surgeries, severe illnesses and emotional stress can cause hair loss. The body simply shuts down production of hair during periods of stress since it is not necessary for survival and instead devotes its energies toward repairing vital body structures. In many cases there is a three month delay between the actual event and the onset of hair loss. Furthermore, there may be another three month delay prior to the return of noticeable hair regrowth. This then means that the total hair loss and regrowth cycle can last 6 months or possibly longer when induced by physical or emotional stress. There are some health conditions which may go undetected that can contribute to hair loss. These include anemia or low blood count and thyroid abnormalities. Both of these conditions can be detected by a simple, inexpensive blood test.
Changing the shape, thickness and length of the eyebrow is a commonly practiced beauty technique. Some people even remove the eyebrow entirely only to replace it with a pencil-drawn mark (eyebrow pencil). As with any part of the body, repeated irritation can eventually lead to hair loss. Sometimes this is due to manual trauma, chemicals from cosmetics or even infections that arise when breaks in the skin occur. While eyebrow modification will not stop as a commonly practised beauty technique, it should at least be minimized.
If you’re stressed out on a regular basis, you may experience excessive hair shedding. Though this is not typically a permanent problem, physical and emotional stress can cause your eyebrow hair follicles to go into a resting phase. After resting phase, follicles enter telogen, or shedding phase, and will begin to shed. Usually, there is a delay between the stress and the shedding phase, sometimes up to 3-4 months. Thankfully, your hair growth should go back to normal again after your stress decreases. However, it can take several months.
MICHAEL REED, MD: Over-the-counter minoxidil, which is the brand Rogaine, is FDA approved. It's been shown to be effective in scientific studies. Propecia is the new drug on the block, and that probably is more effective. It's a pill that you take once a day, and that has been shown to slow down hair loss and grow hair in a significant number of individuals. Most of the other preparations that are heavily advertised or marketed are not proven to be effective.