Alopecia areata: Researchers believe that this is an autoimmune disease. Autoimmune means the body attacks itself. In this case, the body attacks its own hair. This causes smooth, round patches of hair loss on the scalp and other areas of the body. People with alopecia areata are often in excellent health. Most people see their hair re-grow. Dermatologists treat people with this disorder to help the hair re-grow more quickly.
Christiano is more of a skeptic. Lab results are nice, she said, but “you can grow mouse or rat hair sixteen ways till Sunday. They grow beautifully!” She laughed. “Humans, not so much.” She points out that there’s so much we still don’t understand. For one: Why does the hair on the back of men’s heads stick around, even when all the rest drops? She also counsels caution when playing God with hair loss. Some companies are seeking hair-restoration cures by attempting to modify developmental-cell pathways. Those pathways, Christiano says, “are potent, and so it’s tempting, but you have to make sure it’s well enough controlled that you don’t initiate a cancer signal.”
Because hair concealers work like wigs, choosing one that's right for you is important. More than anything, it should be as natural looking and as subtle as possible. Pick one that matches your natural hair color. Most hair fibers come in nine colors, and if you want to achieve a good color fit, you can blend two colors. Apply first the dark color and then the lighter color.
Many other women, though, start noticing thinning hair on top of their heads. Doctors say the defining sign is a widening of the part. The hairline itself is usually intact, but the hair becomes less dense behind it. Doctors will often run a battery of tests to make sure there are no treatable medical conditions, such as anemia, thyroid problems, tumors, or hormonal problems. "Ninety percent of the time, it's normal," Patel said.