Our hair is made of a type of protein called keratin. A single hair consists of a hair shaft (the part that shows), a root below the skin, and a follicle, from which the hair root grows. At the lower end of the follicle is the hair bulb, where the hair's color pigment, or melanin, is produced.

Most people lose about 50 to 100 head hairs a day. These hairs are replaced - they grow back in the same follicle on your head. This amount of hair loss is totally normal and no cause for worry. If you're losing more than that, though, something may be wrong. The medical term for hair loss-losing enough hair that a person has visibly thin or balding patches - is alopecia.

Catastrophic Hair Loss
Hair loss can be the first outward sign that a person is sick, so it may feel scary. Teens who have cancer and lose their hair because of chemotherapy treatments go through a difficult time, especially girls.

It can help to feel like you have some control over your appearance when you're losing your hair. Try some of the many options for disguising hair loss - such as wearing wigs, hair wraps, hats, and baseball caps. For most teens who lose their hair, the hair does return - including after chemotherapy. And hair loss during chemotherapy is usually a sign that the treatment is working to destroy the cancer cells because you can see how it's working on the good cells (your hair!).

Style your hair when it's dry or damp. Styling your hair while it's wet can cause it to stretch and break. And try to avoid teasing your hair, which can also cause damage. Finally, be careful when using chemicals - such as straighteners or color - on your hair.