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.