People who notice hair falling out, thinning, or appearing in large amounts on their comb or brush should consult a dermatologist. With correct diagnosis, many people with hair loss can be helped. A dermatologist will evaluate a patient's hair-loss problem to find the cause so they can determine whether the problem will resolve on its own or medical treatment is needed.

Normal Hair Growth

• About 90 percent of the hair is growing at any one time, and the growth phase lasts between two and six years.
• Ten percent of the hair is in a resting phase that lasts two to three months, and at the end of its resting stage the hair is shed.
• When a hair is shed, a new hair from the same follicle replaces it and the growing cycle starts again.
• Scalp hair grows about one-half inch per month, but as people age their rate of hair growth slows.
• Most hair shedding is due to the normal hair cycle, and losing 50 to 100 hairs per day is expected and is no cause for alarm.

Causes of Excessive Hair Loss

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.

Improper Chemical Treatments

Many men and women use chemical treatments on their hair, including dyes, tints, bleaches, straighteners, and permanent waves. These treatments rarely damage hair if they are done correctly. However, the hair can become weak and break if any of these chemicals are used too often. If hair becomes brittle from chemical treatments, it is best to stop until the hair grows out.

Hereditary Thinning or Balding

Also known as androgenetic alopecia, this is the most common cause of hair loss, and can be inherited from either the mother's or father's side of the family. Women with this trait develop thinning hair, but do not become completely bald. Hereditary hair loss can start in one's teens, twenties, or thirties. While there is no cure, medical treatments are available that may help some people, including:

• Minoxodil, a lotion applied to the scalp twice a day, which can be used by men and women
• Finasteride, an oral prescription medication used by men only which blocks the formation of the active male hormone in the hair follicle

Alopecia Areata

The cause of alopecia areata is unknown, but it is thought to be an autoimmune condition (the body makes antibodies to its own hair) that may affect children or adults of any age. The affected persons are generally in excellent health. This type of hair loss usually causes totally smooth, round patches about the size of a coin or larger. Although rare, it can result in complete loss of scalp and body hair. In most cases the hair regrows; however, dermatologists treat many people with this condition in order to make hair regrow faster.

Alopecia Areata

Treatment includes:

• cortisone injections in the scalp where the hair loss occurred
• topical medications
• a special kind of light treatment
• pills

Telogen Effluvium

Illness, stress, and other factors can cause too many hairs to enter the resting (telogen) phase of the hair growth cycle, and it produces a dramatic increase in the amount of hair shed (effluvium), usually without bald patches. In many cases, telogen effluvium usually resolves in a few months on its own. Causes of telogen effluvium include:

• High Fever, Severe Infection, Severe Flu
• Major Surgery/Chronic Illness
• Thyroid Disease
• Inadequate Protein in Diet
• Low Serum Iron
• Medications
• Birth Control Pills
• Cancer Treatments

Tinea Capitis (Scalp Ringworm)

Caused by a fungal infection, tinea capitis is characterized by patches of scaling that can spread and result in broken hair, redness, swelling, and even oozing on the scalp. This contagious disease is most common in children, and oral medication will cure it.

Trichotillomania (Hair Pulling)

Children, and sometimes adults, will twist or pull their hair, brows, or lashes until they come out. Oftentimes this is just a bad habit that gets better when the harmful effects of that habit are explained. Sometimes hair pulling can be a coping response to unpleasant stresses and occasionally is a sign of a serious psychological problem.

Cicatricial (Scarring) Alopecia

This rare disorder can cause patchy hair loss and associated itching and/or pain. Inflammation around the hair follicle causes damage, scarring, and permanent hair loss in the affected area. The cause or trigger of cicatricial alopecia is unknown. Treatment focuses on stopping the spread of inflammation.

Hair Restoration Surgery

Dermatologists and dermatologic surgeons perform hair restoration surgery to correct hair loss and create a natural-looking hairline. Patients with well-defined baldness, thinning hair, and those with limited hair loss due to scalp injury or burns are generally good candidates for hair replacement surgery.

48-year-old male with male pattern baldness

Seven months later after three sessions

The type of hair replacement surgery chosen depends on the extent and pattern of hair loss. To achieve the best results, a dermatologist may use one or more of the following procedures:

Hair Transplants

Hair transplant surgery is based on the principle of donor dominance, which means that hair from healthy donor sites will take root and grow normally when transplanted into balding, recipient sites. Hair transplantation involves:

• removing small strips of hair-bearing scalp from the back and sides of the head, known as the "donor region," which contains hair that will grow throughout a lifetime
• repairing the donor region, usually resulting in a very narrow scar which is hidden by overlying hair
  
• harvesting strips of hair-bearing scalp and dividing into grafts for placement in the balding areas

The amount of coverage varies depending on the extent of baldness and the specific procedure performed. Within one month, much of the transplanted hair is shed. About two months later, hair starts to grow and continues to grow at a normal rate. After six months, the transplanted hairs begin to take on a natural appearance.

Scalp Reduction

Scalp reduction offers a special benefit to patients with extensive balding. In this procedure, bald areas are reduced or even eliminated by removing several inches of the bald skin, then pulling the sides together and suturing them. Scalp reduction surgery can be performed alone or in conjunction with a hair transplant.

Scalp Extenders or Tissue Expanders

These devices are inserted under the scalp for about three to four weeks to stretch hair-bearing areas, and may be used to increase the effectiveness of scalp reductions. The extender acts like a large rubber band, and the expander works like a balloon, allowing for an even greater reduction in the balding area.

For hair restoration surgery, the patient can expect:

• Treatment performed using local anesthesia in the dermatologist's office, an ambulatory surgery center, or other outpatient facility.
• To resume their normal activities, avoiding strenuous physical exercise until further notified.
• Mild side effects which may include: some swelling and brusing around the eyes after two or three days (which can be minimized by ice compresses and sleeping in a semi-reclined postion), and some numbness at the donor and recipient sites which usually disappears within three months.
• Multiple sessions at various intervals are usually required, and the entire process can take months to years to complete.
• As with all surgical procedures, there is always some risk. However, complications from the surgical treatment of hair loss are rare and generally minimal.

A dermatologist is a physician who specializes in treating the medical, surgical and cosmetic conditions of the skin, hair and nails. To learn more about hair loss and hair restoration, log onto www.aad.org or call toll-free (888) 462-DERM (3376) to find a dermatologist in your area.

To Learn More:
Contact the American Academy of Dermatology (AAD), which represents almost all dermatologists in the U.S. and has more than 16,000 members worldwide. Most of the Academy's members are board-certified in dermatology, which means they have completed a three-year residency and passed a rigorous two-part test administered by the American Board of Dermatology.

Log on to the Academy's Web site at www.aad.org and you can:

• Locate a dermatologist in your area;
• Read information on skin conditions, including more than 65 brochures on individual dermatology topics;
• Get advice about skin cancer prevention and detection, and other ways to care for your skin; and
• Learn about the latest dermatologic procedures and how to make informed decisions about having those procedures.

source : http://www.aad.org/public/publications/pamphlets/common_hairloss.html