A: You are young to have gray hair, but it happens. And usually there's not much you can do about it.
In addition to age, there are a number of factors that contribute to the age at which hair becomes gray. These include:
1. Heredity. Premature graying is common in some families.
2. Gender. Men tend to get gray hair at an earlier age than women.
3. Certain diseases. Examples include vitamin B12 deficiency, thyroid disease and vitiligo (an autoimmune skin disease). Skin conditions, such as eczema or scalp infections, may also cause graying. Such causes may be reversible once the skin disease is treated.
4. Smoking. Those who smoke are more likely to turn gray at a young age.
5. Medications. Certain drugs, such as lithium and methotrexate, can cause hair to fall out, making the remaining gray hair more noticeable.
A common misconception is that stress turns hair gray. There are rare examples of people suddenly losing pigmented (darker) hair, which makes their gray hair more noticeable, but everyday stress or worry does not change hair color.
Researchers are looking for ways to restore the capacity of melanocytes to produce melanin after hair turns gray. Until then, there are only a few ways to handle the situation: Color your hair, shave your head, or do nothing.
I recommend a checkup with your doctor to make sure you are in good health and to look for reversible causes of premature graying. Most of the time, there is no disease, condition or other identifiable reason for premature graying. And unfortunately, no way to stop the process.
(Robert H. Shmerling, M.D., is a practicing physician in rheumatology at Beth Israel Deaconess Medical Center, Boston, Mass., and an Associate Professor in Medicine at Harvard Medical School.)
(For additional consumer health information, please visit http://www.health.harvard.edu.)