Learn about the many causes of hair loss.
According to the American Dermatological Association (ADA), a certain amount of hair loss (also known as alopecia) is completely normal, even healthy, for most people. As long as only about 50 to 100 hairs are shed a day, there should be no cause for alarm. However, individuals should visit a dermatologist if they notice hair thinning or falling out at an abnormal pace. Such symptoms may be signs of a more serious problem and should be addressed immediately. The National Institute of Health (NIH) cites aging, genetics, diseases, diet and medication, among other factors that cause of hair loss.
The most simple-to-resolve causes of hair loss are damaging hair care practices. Wearing hair in tight braids or pigtails can cause traction alopecia, which may lead to the scarring of the scalp and the prevention of future hair growth. Hair treatments including hot oil, chemical "perming" or straightening, dyeing and bleaching can also cause inflammation and irritation of hair follicles, which may lead to scar tissue and decreased hair growth.
The most common type of hair loss is hereditary thinning or balding, scientifically known as androgenetic alopecia. Both men and women can experience this, which exacerbates the natural hair loss that follows aging. It most obviously manifests in men (beginning as early as their 20s for some), thus the nickname "male pattern baldness."
There is currently no cure for hereditary hair loss, although certain some lotions (applied to the scalp) and oral medications may prove helpful in either regenerating some of the thinned hair, or preventing further hair loss. Solutions as simple as toupees or as complicated as hair transplant surgery are also available.
In addition to poor nutrition -- namely diets low in protein -- hair loss can be traced to health problems like lupus and diabetes. Certain types of cancer treatments, such as chemotherapy, may also cause hair loss. Illnesses that result in high fever or infection can cause hair loss, as can major surgery and other medical emergencies that put stress on the body.
Women may experience hair loss shortly after giving birth due to the fluctuation of hormone levels in the body and thyroid problems can lead to hair loss due to similarly vacillating hormones. Some prescription medications can also induce hair loss.
Several more unusual conditions include hair loss as a primary symptom. Trichotillomania in its mildest form is the habit of a person pulling out his or her own hair, eyebrows and eyelashes, though it can be a symptom of more severe psychological issues and should be addressed by a doctor if serious.
An autoimmune condition called alopecia areata -- in which the patient's otherwise healthy body begins fighting hair as though it were an invasive disease -- also leads to extreme hair loss, from quarter-sized patches to total body hair loss. Cicatricial alopecia, a rare disorder which results from unknown causes, leads to hair loss and extreme itchiness, that may result in further irritation and hair loss in the affected area. Neither a cause nor cure is known for either disease, though some effective treatments have been developed, including anti-inflammatory medications to slow the spread of cicatricial alopecia, and cortisone injections, topical medications and oral medication for alopecia areata.