What causes hair loss?

Common causes of hair loss include:

Family history. In most cases, hair loss is inherited, which means it's passed down from one or both of your parents. This is called male-pattern or female-pattern hair loss.
Stress, including physical stress from surgery, illness, or high fever.
Chemotherapy, which is powerful medicine that destroys cancer cells.
Damage to your hair from pulling it back too tightly, wearing tight braids or ponytails, or using curling irons or dyes.
Age. You grow less hair as you get older. Hair also gets thinner and tends to break more easily as you age.
Poor diet, especially not getting enough protein or iron.
Thyroid diseases, such as hypothyroidism and hyperthyroidism.
Ringworm of the scalp, which is common in children.

What are the symptoms?

Your symptoms will depend on what kind of hair loss you have.

If your hair is thinning, it happens slowly over time, so you may not notice the hairs falling out. If your hair is shedding, then clumps of hair fall out. You may lose hair all over your scalp, which is called general hair loss. Or you may lose hair only in one area, which is called focal hair loss.

With inherited hair loss, men usually get bald spots around the forehead or on the top of the head, while women have some thinning all over the scalp, but mostly on the top of the head.

Since your hair has a lot to do with your appearance, losing it may cause you to have lower self-esteem if you don't like how you look. This is especially true in women and teens.