Hair loss, either temporary or permanent, may occur for a variety of reasons. Hair loss may be reversed through medication or surgical procedures. The loss of one's hair can cause concern as attractiveness and youth are often linked to the presence of hair. Hair loss usually develops gradually and may be patchy or diffuse.
- Alopecia is the medical term for hair loss.
- Baldness is a common term for total hair loss on the scalp.
Hair loss may be permanent or temporary
- The most common type of permanent hair loss is [[Androgenetic alopecia|male pattern baldness (androgenetic alopecia)]]. Male-pattern baldness may begin in the late teens or early twenties. It is characterized by receeding hair at the temples and balding at the top of the head. It may progress to total baldness.
- Female pattern baldness is characterized by thinning at the front, sides and crown of the head. It rarely progresses to total baldness.
- Inflammation of the scalp may lead to cicatricial (scarring) alopecia. Because the hair follicle is damaged in this condition, the hair will not grow back.
- Alopecia areata is an autoimmune disorder which causes hair loss on the scalp or other parts of the body. The hair loss pattern is typically round, smooth patches. The hair loss may be associated with itching or soreness.
- Telogen effluvium is a sudden hair loss which is diffuse. Hair comes out in clumps and is distributed evenly on the scalp.
- Traction alopecia is caused by mechanical traction on the hair. Common precipitators include tight rollers, braids, or cornrows. Hair loss occurs between braids or cornrows or at the site where the hair is pulled.
- Chemotherapy or radiation given during cancer treatment may induce hair loss. Hair generally returns once treatment is finished.
Common symptoms of hair loss include:
- Thinning hair on the scalp, a receding hairline, or a horseshoe-shaped pattern that leaves the crown of the head exposed (androgenic alopecia in men)
- Thinning of hair at the crown (androgenic alopecia in women)
- Sudden loss of patches of hair, usually in a smooth circular pattern (alopecia areata).
- Complete loss of all hair on the body (a rare disease called alopecia universalis)
- Patches of broken hairs and incomplete hair loss, usually on the scalp but sometimes involving the eyebrows. This condition (trichotillomania) often occurs in children and is associated with a history of rubbing or pulling at hair.
- Loss of "clumps" of hair after various illnesses and drug treatments, rapid weight loss, anemia, stress, or pregnancy (telogen effluvium)
Roughly 100 hairs are lost from the average head every day. The average scalp contains about 100,000 hairs. Each individual hair survives for an average of four and a half years, during which time it grows about half an inch a month. Usually in its fifth year, the hair falls out and is replaced within six months by a new one. There are three stages of hair growth: 
- The anagen phase lasts for about three years. Most hair is in this stage at any point in time.
- The transitional or catagen phase contains a small percentage of hair at a time (2%-3%).
- The final, or telogen phase contains about 10% of hair. This is a resting phase which lasts about three months. When the hair dies, it is ejected and a small nodule is left at the hair shaft.
Because hair is in each of the three phases at a given time, normal loss of hair is gradual and not generally noticed.
Genetic baldness is caused by the body's failure to produce new hairs and not by excessive hair loss. Both men and women tend to lose hair thickness and amount as they age. Inherited or "pattern baldness" affects many more men than women. About 25% of men begin to bald by the time they are 30 years old, and about two-thirds are either bald or have a balding pattern by age 60. Currently 35 million men suffer from hair loss in the United States. By age 50, half of all men experience some level of hair loss.
In addition to the causes listed above, some other causes of hair loss include:
- Autoimmune conditions such as Systemic Lupus Erythematous
- Certain infectious diseases such as syphilis
- Emotional or physical stress
- Excessive shampooing and blow-drying
- Hormonal changes -- for example, thyroid disease, childbirth, or use of birth control pills
- Nervous habits such as continual hair pulling or scalp rubbing (trichotillomania)
- Radiation therapy
- Tinea capitis (ringworm of the scalp)
- Tumor of the ovary or adrenal glands
The diagnosis of hair loss in both men and women is fairly straightforward. A history of the hair loss is first obtained. Common questions include:
- When the hair loss was first noticed
- If the hair loss is diffuse or localized
- Whether the loss was gradual or sudden
- Any physical, medical or emotional stressors in the past several months (pregnancy, illness, infection or surgery.
- History of tight braids or cornrows
- A history of tugging at the hair
- Any other signs or symptoms of hormone imbalance (menstrual abnormalities, infertility, dry skin, tremor, palpitations)
- Use of any medications
If determination of hair loss is not fully clear, a hair pull and hair scrape test may be applied to make a hair loss determination.
- Hair pull tests are done by taking twenty to thirty strands of hair and gently pulling on them. If five to seven hair follicles pull out, this will usually indicate a problem with hair loss. The hair can then be examined under a microscope to look for breakage or signs of fungal infection (tinea capitis, trichotillomania, traction alopecia), or unsusual shape (alopecia areata).
- Scalp biopsy is rarely used if the diagnosis is unclear or the scalp fails to respond to treatment.
- Laboratory tests may also be done. The results may help with diagnosing autoimmune disorders, pernicious anemia, or hormone disorders. These laboratory tests include CBC, thyroid function tests, prolactin levels, anti-nuclear antibody levels, and erythrocyte sedimentation rate (ESR).
- Hair loss from menopause or childbirth often returns to normal six months to two years later.
- For hair loss caused by illness (such as fever), radiation therapy, or medication use, no treatment is necessary. The hair will usually grow back when the illness has ended or the therapy is finished. A wig, hat, or other covering may be desired until the hair grows back.
- For hair loss due to heredity, age, and hormones, the topical medication minoxidil (Rogaine) can be helpful for both male and female pattern baldness. Minoxidil is now available without a prescription as a 2% solution (for men and women) and an extra strength 5% solution (for men only) 
- The oral medication Propecia (finasteride) is effective for hair regrowth in some men. It works by decreasing dihydrotestosterone (DHEA) levels in blood and on the scalp and has been clinically proven to slow hair loss and increase hair growth. Finasteride is not FDA approved for use in women.
- Spironolactone, a diuretic, slows hair loss in women.
- Estrogen may also prevent further hair loss in women although it does not appear to help with hair regrowth.
- Hair transplantation (performed by a physician) is a surgical approach which involves transferring growing hair from one part of the head to another. It is somewhat painful and expensive, but usually permanent.
- Hair weaves, hair pieces, or changes of hair style may disguise hair loss. This is generally the least expensive and safest approach to hair loss. Hair pieces should not be sutured to the scalp because of the risk of scars and infection.
Holistic and alternative treatments
There are several key holistic approaches that will encourage healthy hair growth.
- Eating a well-balanced diet careful to balance the level of sugar assumption
- Quality of sleep you have every night
- Daily moderate weight-lifting which will naturally boost HGH levels
- Reducing stress as much as possible
- Eating foods that decrease levels of dihydrotestostrone(DHT), a hormone that increases baldness, will help reverse the amount of balding. Such foods like herb saw palmetto berry, plant sterols, and other botanicals.
ClinicalTrials.gov has a number of open studies relating to hair loss. Information is available here
There is some exciting research in the field of hair loss. Areas studied include:
- Using injections of botulinum toxum to treat alopecia areata
- Comparing spironolactone to minoxidil in the treatment of female pattern hair loss
- Development of a new topical medicine to treat female pattern hair loss after menopause
- Possible effects of steroid injections used to treat alopecia areata on the adrenal gland
- Creating a national alopecia areata registry to understand the genetics of the disease in order to develop better treatment
- Efficacy of ultraviolet light in the treatment of alopecia areata
More information about these research projects can be found on ClinicalTrials.gov.
- ↑ 1.0 1.1 Springer K, Brown M, Stulberg D. Common Hair Loss Disorders. American Family Physician. 2003; 68(1): 93-102. PDF
- ↑ Hillmer A, Hanneken S, Ritzmann S, et al. Genetic Variation in the Human Androgen Receptor Gene Is the Major Determinant of Common Early-Onset Androgenetic Alopecia. Am J Hum Genet. 2005 July; 77(1): 140–148. Published online 2005 May 18. PDF