Baldness involves the state of lacking hair where it often grows, especially on the head. The most common form of baldness is a progressive hair thinning condition called androgenic alopecia or “male pattern baldness” that occurs in adult male humans and other species. The amount and patterns of baldness can vary greatly; it ranges from male and female pattern alopecia (androgenic alopecia, also called androgenetic alopecia or alopecia androgenetica), alopecia areata, which involves the loss of some of the hair from the head, and alopecia totalis, which involves the loss of all head hair, to the most extreme form, alopecia universalis, which involves the loss of all hair from the head and the body.

What is the normal cycle of hair growth and loss?

The normal cycle of hair growth lasts for 2 to 6 years. Each hair grows approximately 1 centimeter (less than half an inch) per month during this phase. About 90 percent of the hair on your scalp is growing at any one time. About 10 percent of the hair on your scalp, at any one time, is in a resting phase. After 2 to 3 months, the resting hair falls out and new hair starts to grow in its place.

It is normal to shed some hair each day as part of this cycle. However, some people may experience excessive (more than normal) hair loss. Hair loss of this type can affect men, women and children.

Baldness, also known as alopecia, is hair loss, or absence of hair. Baldness is usually most noticeable on the scalp, but can occur anywhere on the body where hair grows. The condition is more common in men than in women.
What causes hair loss?

Hair loss is believed to be primarily caused by a combination of the following:

• aging
• change in hormones
• illness
• family history of baldness
• burns
• trauma

However, hair loss is not caused by the following:

• poor circulation to the scalp
• vitamin deficiencies
• dandruff
• excessive hat-wearing
• a gene passed on from an individual’s maternal grandfather

Generally, the earlier hair loss begins, the more severe the baldness will become.

What are the different types of baldness?

Baldness can be classified into various types, depending on the cause. Several of the many different types of baldness include the following:

• female-pattern baldness
  Although less common, female-pattern baldness differs from that of male-pattern baldness in that the hair generally thins all over the head, but the frontal hairline is maintained. Female-pattern baldness rarely results in total hair loss.
• male-pattern baldness
  Male-pattern baldness usually is a hereditary condition. The condition may begin at any age. Hair loss often begins on the front, sides, and/or on the crown of the head. Some men may develop a bald spot or just a receding hair line, while others may lose all of their hair.
• alopecia areata
  This hair loss disorder is characterized by sudden loss of hair in one particular area, which grows back after several months. However, if all body hair is suddenly lost, regrowth may not occur. The cause of this type of hair loss is unknown.
• toxic alopecia
  Toxic alopecia may occur following a high fever or severe illness. Certain medications, especially thallium, high doses of vitamin A, and retinoids, may cause toxic alopecia. Medical conditions, such as thyroid disease, and after giving birth may also trigger toxic alopecia. The condition is characterized by temporary hair loss. Also, some cancer medications can cause hair loss.
• scarring alopecia
  Scarred areas may prevent the hair from growing back. Scarring may occur from burns, injury, or x-ray therapy. However, other types of scarring that may cause hair loss can be caused by diseases such as lupus, bacterial or fungal skin infections, lichen planus, sarcoidosis, tuberculosis, or skin cancer.
• trichotillomania (hair pulling)
  Hair pulling, a habit most common among children, may cause hair loss.

What Can Doctors Do?

If you see a doctor about hair loss, he or she will ask questions about your health and family health (called a medical history) and check your scalp. In some cases, the doctor might take hair samples and test for certain medical conditions that can cause hair loss.

If medication is causing hair loss, ask the doctor if you can take a different drug. If your hair loss is due to an endocrine condition, like diabetes or thyroid disease, proper treatment and control of the underlying disorder is important to reduce or prevent hair loss.

If your doctor recommends it, a product like minoxidil that can speed up hair growth also might be helpful. Alopecia areata can be helped by treatment with corticosteroids. If nutritional deficiencies are found to be causing your hair loss, the doctor might refer you to a dietitian or other nutrition expert.

Catastrophic Hair Loss

Hair loss can be the first outward sign that a person is sick, so it may feel scary. Teens who have cancer and lose their hair because of chemotherapy treatments (especially girls) might go through a difficult time.

It can help to feel like you have some control over your appearance when you’re losing your hair. When getting chemotherapy, some people like to cut their hair or shave their heads before the hair falls out. Some even take the hair they cut off and have it made into a wig. Many options can help disguise hair loss — such as wearing wigs, hair wraps, hats, and baseball caps. For most teens who lose their hair, the hair does return — including after chemotherapy.

Taking Care of Your Hair

Eating a balanced, healthy diet is important for a lot of reasons, and it really benefits your hair.

If you’re losing hair, some doctors recommend using baby shampoo, shampooing no more than once a day, and lathering gently. Don’t rub your hair too vigorously with a towel, either. Many hair experts suggest you consider putting away the blow dryer and air drying your hair instead. If you can’t live without your blow dryer, try using it on a low heat setting.

Style your hair when it’s dry or damp. Styling your hair while it’s wet can cause it to stretch and break. And try to avoid teasing your hair, which can cause damage. Finally, be careful when using chemicals — such as straighteners or color — on your hair, and avoid frequent use of chemical treatments.