The top reason for hair loss in most cases is the hormone DHT which damages the hair follicles. This is naturally present in men and those who go bald do so because of both the hormone and their genes. In women, hormonal fluctuations could lead to lower than normal estrogen levels. Estrogen is supposed to balance and regulate DHT. With less estrogen, DHT has a stronger effect.
Severe Illness
Thyroid and Infections - A serious thyroid disorder could be your reason for hair loss. Aside form thyroid problems though, other severe illnesses such as high fever and infections could shock your system and cause your hair to temporarily fall out at a faster rate.
Nutrient Deficiency
Nutritional Deficiencies - As some studies would show, being deficient in some vitamins and minerals could be the reason for hair loss. Individuals who have diets low in protein and some B-complex vitamins may experience temporary hair loss. The lack of iron or the inability of the body to completely absorb iron may also cause your hair to shed faster. The only logical solution to this problem would be to eat right and take supplementation.
Medications
Medications - We all know that certain cancer treatment can cause massive hair loss. There are however, other medication types that could be the reason for hair loss. Some steroids and blood thinners are examples of these medicines.
Major Operation
A major operation is both a physically and emotionally traumatic experience for some. A person could still continue losing hair even a month or more after the operation. Often though, a person will stop losing his hair as soon as he completely recuperates from the surgical procedure.
Stress
There are some sources that try to downplay stress as a cause for hair loss. Stressful situations however could lead to a condition called telogen effluvium. Constant and extreme bombardment of physical or emotional stress could push some of the hair strands in the growing phase prematurely into the resting phase. Eventually, these hair strands will begin to shed.
Infection
Ringworms could infest the scalp and cause hair loss. This unsightly and uncomfortable reason for hair loss is a form of scalp infection.
Hairstyles
As long as you moderately use hairstyling products, you're safe from hair loss. It is generally agreed upon though that using too much of these hair products and rigorous hair blow drying could damage the hair severely. In some people the main reason for hair loss would be certain hairstyles. Tight braiding and pony tailing could uproot hair strands. In severe cases, the scalp injury could develop scar tissue in which case it would be difficult to re-grow hair.
Auto-Immune Disorder
Alopecia aratea is a rare condition among individuals but it is still considered to be a possible major reason for hair loss. In this condition, the immune system mistakenly attacks the follicle cells. The attack damages the cells and causes hair loss.
