Illnesses or medical conditions: Endocrine (hormonal) conditions, such as uncontrolled diabetes or thyroid disease, can interfere with hair production and cause hair loss. People with lupus can also lose hair. The hormone imbalance that occurs in polycystic ovary syndrome can cause hair loss in teen girls as well as adult women.

Excess hair loss can have many different causes. Hair will regrow spontaneously in some forms of hair loss. Other forms can be treated successfully by a dermatologist. For the several forms of hair loss for which there is no cure at present, there is research in progress that holds promise for the future. Talk to your dermatologist about the best options for you.

Hormonal problems may cause hair loss. If your thyroid gland is overactive or underactive, your hair may fall out. This hair loss usually can be helped by treatment thyroid disease. Hair loss may occur if male or female hormones, known as androgens and estrogens, are out of balance. Correcting the hormone imbalance may stop your hair loss.

Alopecia areata: This is classified as an autoimmune disease, but the cause is unknown. People who develop alopecia areata are generally in good health. A few people may have other autoimmune disorders including thyroid disease. Some scientists believe that some people are genetically predisposed to develop alopecia areata and that a trigger, such as a virus or something else in the environment, sets off the condition. A family history of alopecia areata makes you more likely to develop it. With alopecia areata, your hair generally grows back, but you may lose and regrow your hair a number of times.

The main cause of female and male hair loss is due to the effects of a hormone byproduct called DHT (Di Hydrotestosterone) on the hair follicle. DHT is created indirectly from the hormone Testosterone, which is converted to DHT by certain enzymes in the body naturally.

Hair loss is a natural daily phenomenon, re-growth is generally a given. But this shedding of hair cannot be the main cause of hair loss. Every strand of hair on a human head is genetically programmed to a cycle that includes growth, stabilization, aging and shedding. On the average, a human head sheds about 50 - 125 (depending on gender) but most of them will come back after the resting stage as the follicle itself is not destroyed. Trouble begins when the loss exceeds re-growth, or the re-growth is weak and unhealthy. These are the main causes of hair loss.

This myth has been used to sell hair loss products as bizarre as a device that allows you hang upside down in your closet overnight in order to restore blood flow. But as Paul McAndrews, MD, a board-certified dermatologist and hair restoration surgeon and a clinical professor at the University of California School of Medicine, explains, "Blood supply is excellent in the balding region, which is why hair transplant works so well."

High fever, severe infection, major surgery, significant life stressor from four weeks to three months after a person has a high fever, severe infection, major surgery, or significant life stressor such as death in the family, he or she may be shocked to see a lot of hair falling out. This condition usually corrects itself but may require treatment.