Causes and risk factors
In male pattern baldness, which tends to be inherited, the hair is usually lost at the temples and the crown. This happens because of an excess of a chemical called dihydrotestosterone, or DHT, which causes the hair follicles to make thinner and thinner hair until they eventually pack up completely.
Other causes of hair loss, which may not follow this pattern, include:
Iron-deficiency anemia
Under active thyroid
Fungal scalp infection
Some prescribed medicines
Stress
