Hair passes through four phases during its growth cycle. At any one time, different hairs on your head and body are in different phases and it is the balance of these that keeps the volume of your hair pretty much constant.
There is the growth or anagen phase; the transition or catagen phase; the resting or telogen phase; and the returning growth or mesanagen phase. The full cycle can take between two and five years to run through. If follicles are stuck in the telogen phase, hair loss will slowly become apparent, particularly if those hairs affected are all in the same spot.
There can be a number of causes for hair loss and these might be:
• Stress
• A hormonal imbalance
• Genetic predisposition
• A thyroid disorder
• Poor diet
• Cosmetic treatments
• Certain medication
The important thing to remember is that if you are losing hair due to too many follicles being in the resting phase, there is every chance that the condition can be reversed as the follicles themselves are not damaged in any way.
In any hair loss situation, your first step should be to consult your doctor, who may refer you to a dermatologist to diagnose the cause of the condition.