What are the causes of severe hair fall?

Rapid hair loss can occur from many causes, including illness, stress, medications, and hormone changes. Not all hair loss is a result of abnormal conditions. Hair loss can result from normal shedding. At times, shedding may be greater than usual. This can occur during "telogen effluvium," a normal "resting" phase of hair growth. Hair loss can also result with normal aging. This type of hair loss, called "androgenic alopecia," often has an inherited component.