It is normal to shed some hair each day as part of this cycle. However, some people may experience excessive (more than normal) hair loss. Hair loss of this type can affect men, women and children.
A great number of things can cause excessive hair loss or alopecia:

• stress
• illness
• hormonal problems (thyroid hormons, male or female hormones)
• pregnancy (3 months after baby was born)
• some medicines
• infections
• underlying disease, such as lupus or diabetes

The term "common baldness" usually means male-pattern baldness, or permanent-pattern baldness. Male-pattern baldness is the most common cause of hair loss in men. Men who have this type of hair loss usually have inherited the trait. In male-pattern baldness, hair loss typically results in a receding hair line and baldness on the top of the head.