There are many causes of scalp hair loss. This article will cover the common ones.

In general, most hair loss is not associated with systemic or internal disease, nor is poor diet a frequent factor. Thyroid disease can cause hair loss, but thyroid tests on people who have ordinary hair loss are usually normal. Although many medications list “hair loss” among their potential side effects, drugs are also not overall common causes of thinning or lost hair. On the other hand, with cancer treatments and immune suppression medications, hair loss is not uncommon.

One useful way to classify hair loss is by whether the loss is localized and patchy, or whether it affects large areas or the whole scalp.

Patchy hair loss

Some conditions produce small areas of hair loss, while others affect large areas of the scalp. Common causes of patchy hair loss are:

* alopecia areata (patches of baldness that usually grow back)
* traction alopecia (thinning from tight braids or ponytails)
* trichotillomania (the habit of twisting or pulling hair out)
* tinea capitis (fungal infection)

Alopecia areata

A common condition, alopecia areata usually starts as a single, quarter-sized circle of perfectly smooth baldness. Alopecia patches usually regrow in three to six months without treatment. Sometimes, hair grows back in white. In another variant, alopecia can produce two or three bald patches. When these grow back, they may be replaced by others. The most extensive form is called alopecia totalis, in which the entire scalp goes bald. It’s important to emphasize that patients who have localized hair loss generally don’t go on to lose hair all over the scalp. Alopecia can affect hair on other parts of the body too– for example, the beard.

Alopecia areata is considered an autoimmune condition, in which the body attacks itself (in this case its own hair follicles). Most alopecia patients, however, do not have systemic problems and need no medical tests. Alopecia is also often blamed on “stress,” but in fact it’s usually the other way around: having alopecia causes the stress, at least until people find out what it is.

Treatments for alopecia areata include injecting steroids into affected patches to stimulate hair growth. This is not practical for large areas. Other treatments, such as oral steroids or ultraviolet light therapy, are either toxic or impractical. In most mild cases, patients can comb over the affected areas. In more severe and chronic cases, some patients wear hairpieces; nowadays some men shave their whole scalp, now that this look has become fashionable.

Traction alopecia

Tight braids and ponytails can pull hard enough on hairs to make them fall out. If this happens, it’s best to choose hairstyles that put less pressure on hair roots. The sooner this is done the better, to avoid permanent damage.

There is no cure for common baldness, but surgical hair replacement can give you back a head of your own hair. Available since the 1950s, surgical hair replacement is a low-risk procedure.

Surgeons remove tiny plugs (grafts) of your hair-bearing skin and transplant them into tiny holes made in your scalp. They take these plugs from the band of hair extending from above your ears around the back of your scalp.

During one session, your surgeon may transplant between 60 and 100 hair plugs, each about the diameter of a pencil eraser. Local anesthesia and mild sedation minimize discomfort during surgery.

Hospitalization usually is unnecessary. Within a few days after the operation, tiny scabs form around each hair graft. When the scabs disappear, the donor hairs usually fall out. New hairs generally start to grow within a few months.

If the baldness and thinning is extensive, one should not expect to walk out of the first surgery with a full, natural-looking head of hair. Even after the transplanted hairs begin growing, these widely scattered clumps may look conspicuous. Additional surgeries may be needed to fill the void. It may take a year or two before you will be pleased with your new appearance.

The quest for a new look may cost in the range of $2,000 for each round of surgery. Typically, it takes three or fours sessions to cover a bald area.

Under normal conditions, scalp hairs live for about three years (the anagen, or growing, phase); they then enter the telogen, or resting, phase. During this three-month period, the hair root shrivels up into a small white “club,” then the hair falls out. It is therefore normal to lose about 100 hairs every day, more of them on days when shampooing loosens the hairs that are ready to fall out. The hairs are then replaced by the body.

Sometimes people worried about losing their hair start noticing hairs on their pillow or in the sink, not realizing that they’ve always been there. A close look at these will usually reveal the white “club” at the end, showing that these hairs were already dead. Normally, about 10% of scalp hairs are in the telogen phase.

There are several circumstances that produce a “shock to the system” that alters the hair growth rhythm. As a result, as much as 30-40% of the hairs can cycle into telogen. Three months later hairs come out in a massive shedding (effluvium), especially near the front of the scalp. These include:

* childbirth
* high fever
* sudden weight loss (crash dieting)
* surgery

None of these has to be life-threatening, nor does hair loss always follow them. (It can happen after one pregnancy but not the next.) But when the hair falls out, it’s all over the place–covering the pillow, clogging the drain, and so forth. Paradoxically, the more dramatic the hair loss, the better the prognosis, because when the body gets back into normal rhythm, most if not all of that hair comes back. No special treatment is needed. Normal shampooing can continue, because this only loosens hairs that were going to come out anyway.

Even men who never “go bald” thin out over the years. Unlike those with reversible telogen shedding, those with common male-pattern hair loss don’t notice much hair coming out; they just see that it’s not there anymore. Adolescent boys notice some receding near the temples as their hairlines change from the straight-across boys’ pattern to the more “M-shaped” pattern of adult men. This normal development does not mean they are losing hair.

Some “myths” about male-pattern baldness

* You inherit baldness through your mother’s male relatives. Actually, baldness can come from either side of the family, or both. Looking at your family can give you at best an educated guess about how you’ll turn out.

* Longer hair puts a strain on roots. They don’t. And hats don’t choke off the circulation to the scalp to cause hair loss either.

* Shampooing does not accelerate balding.

* “Poor circulation” does not cause hair loss, and massaging doesn’t stop it.

Many conditioners, shampoos, vitamins, and other products claim to help hair grow in some unspecified way. These are harmless but useless. To slow down hair loss, there are two basic options:

* Minoxidil (brand name: Rogaine): This topical application is over-the-counter, no prescription is required. It works best on the crown, less on the frontal region. Available as a 2% solution, Rogaine may grow a little hair, but is better at holding onto what’s still there. There are few side effects with Rogaine. The main problem with this treatment is the need to keep applying it twice a day, and most men get tired of it after a while. In addition, Minoxidil works less well on the front of the head, which is where baldness bothers most men. This drug also comes in a higher strength, 5%, which may be a bit more effective.

* Finasteride (brand name: Propecia): This is a lower-dose version of a drug that shrinks prostates in middle-aged men. Propecia is by prescription and is taken once a day. Propecia does grow and thicken hair to some extent, but its main use is to keep hair that’s still there. It’s therefore best for men who still have enough hair to retain. One side effect is impotence, but this is no more common than it is in the general population, and is reversible when the drug is stopped. Taking Propecia once a day is easier that applying minoxidil, but the prospect of taking a pill daily for years doesn’t sit well with some men

Female-pattern baldness

Women lose hair on an inherited (genetic) basis too, but the female pattern is more diffuse, with less likelihood of the frontal hairline being lost. Although some women may notice hair thinning as early as their 20s, the pace of hair loss tends to be gradual, often taking years to become obvious to others. (It’s common to hear women with what appear to have a full head of hair exclaim, “This is nothing–you should have seen how thick it used to be!”)

Notions about baldness being inherited through the mother’s family, just like stories about hats choking off follicles or long hair pulling on the roots, are just folklore.

Hair loss “myths” of special concern to women:

* Longer hair does not put a strain on roots.

* Shampooing does not accelerate hair loss; it just removes those that were ready to fall out anyway.

* Coloring, perming, and conditioning the hair do not usually cause hair loss. Styles that pull tight may cause some loss, but hair coloring and “chemicals” don’t.

Common baldness, sometimes called male- or female-pattern baldness, accounts for 99 percent of hair loss in men and women. Although its exact causes are unknown, heredity, hormones and age are contributing factors. Unlike hair loss resulting from disease or other non-hereditary factors, hair loss due to common baldness is permanent.

Male baldness usually begins with thinning at the hairline, followed by the appearance of a thinned or bald spot on the crown of the head.

Women with common baldness rarely develop bald patches. Instead, they experience a diffuse thinning of their hair.

Hair is a conspicuous element in many cultural definitions of fashion, youth and sexuality. So, it is not surprising that many cringe at the first sign of thinning hair.

Most people lose between 50 and 100 strands of hair daily, with little impact. As hairs fall out naturally, new hairs grow in. So there is no need to despair if you spot a hair or two in your sink. However, with age this natural regrowth process may slow or stop, and thinning and baldness may occur. If you are concerned about it, see your doctor for an evaluation to find out if your hair loss is due to an underlying medical disorder.

Like your skin and nails, your hair goes through a finely tuned cycle of growth and rest. Excessive hair loss can occur at any time this delicate cycle is upset.

A hair grows from its follicle at an average rate of about 1/2 inch per month. Each hair grows for 2 to 6 years, then rests, and then falls out. A new hair soon begins growing in its place. At any time, about 85% of the hair is growing and 15% is resting.

Baldness occurs when hair falls out but new hair does not grow in its place. The cause of the failure to grow new hair in female pattern baldness is not well understood, but it is associated with genetic predisposition, aging, and levels of endocrine hormones (particularly androgens, the male sex hormones).

Changes in the levels of androgens can affect hair production. For example, after the hormonal changes of menopause, many women find that the hair on the head is thinned, while facial hair is coarser. Although new hair is not produced, follicles remain alive, suggesting the possibility of new hair growth.

Female pattern baldness is usually different from that of male pattern baldness. The hair thins all over the head, but the frontal hairline is maintained. There may be a moderate loss of hair on the crown, but this rarely progresses to total or near baldness as it may in men.

Hair loss can occur in women for reasons other than female pattern baldness, including the following:

* Temporary shedding of hair (telogen effluvium)
* Breaking of hair (from such things as styling treatments and twisting or pulling of hair)
* Patchy areas of total hair loss (alopecia areata — an immune disorder causing temporary hair loss)
* Medications
* Certain skin diseases
* Hormonal abnormalities
* Iron deficiency
* Underactive thyroid
* Vitamin deficiency

The cause of BPH is not well understood. No definite information on risk factors exists. For centuries, it has been known that BPH occurs mainly in older men and that it doesn’t develop in men whose testes were removed before puberty. For this reason, some researchers believe that factors related to aging and the testes may spur the development of BPH.

Throughout their lives, men produce both testosterone, an important male hormone, and small amounts of estrogen, a female hormone. As men age, the amount of active testosterone in the blood decreases, leaving a higher proportion of estrogen. Studies done on animals have suggested that BPH may occur because the higher amount of estrogen within the gland increases the activity of substances that promote cell growth.

Another theory focuses on dihydrotestosterone (DHT), a substance derived from testosterone in the prostate, which may help control its growth. Most animals lose their ability to produce DHT as they age. However, some research has indicated that even with a drop in the blood’s testosterone level, older men continue to produce and accumulate high levels of DHT in the prostate. This accumulation of DHT may encourage the growth of cells. Scientists have also noted that men who do not produce DHT do not develop BPH.

Some researchers suggest that BPH may develop as a result of “instructions” given to cells early in life. According to this theory, BPH occurs because cells in one section of the gland follow these instructions and “reawaken” later in life. These “reawakened” cells then deliver signals to other cells in the gland, instructing them to grow or making them more sensitive to hormones that influence growth.

Men who have BPH with symptoms usually need some kind of treatment at some time. However, a number of researchers have questioned the need for early treatment when the gland is just mildly enlarged. The results of their studies indicate that early treatment may not be needed because the symptoms of BPH clear up without treatment in as many as one-third of all mild cases. Instead of immediate treatment, they suggest regular checkups to watch for early problems. If the condition begins to pose a danger to the patient’s health or causes a major inconvenience to him, treatment is usually recommended.

Since BPH can cause urinary tract infections, a doctor will usually clear up any infection with antibiotics before treating the BPH itself. Although the need for treatment is not usually urgent, doctors generally advise going ahead with treatment once the problems become bothersome or present a health risk.

The following section describes the types of treatment that are most commonly used for BPH.
Drug Treatment

Over the years, researchers have tried to find a way to shrink or at least stop the growth of the prostate without using surgery. The FDA has approved six drugs to relieve common symptoms associated with an enlarged prostate.

Finasteride (Proscar), FDA-approved in 1992, and dutasteride (Avodart), FDA-approved in 2001, inhibit production of the hormone DHT, which is involved with prostate enlargement. The use of either of these drugs can either prevent progression of growth of the prostate or actually shrink the prostate in some men.

The FDA also approved the drugs terazosin (Hytrin) in 1993, doxazosin (Cardura) in 1995, tamsulosin (Flomax) in 1997, and alfuzosin (Uroxatral) in 2003 for the treatment of BPH. All four drugs act by relaxing the smooth muscle of the prostate and bladder neck to improve urine flow and to reduce bladder outlet obstruction. The four drugs belong to the class known as alpha blockers. Terazosin and doxazosin were developed first to treat high blood pressure. Tamsulosin and alfuzosin were developed specifically to treat BPH.

The Medical Therapy of Prostatic Symptoms (MTOPS) Trial, supported by the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), recently found that using finasteride and doxazosin together is more effective than using either drug alone to relieve symptoms and prevent BPH progression. The two-drug regimen reduced the risk of BPH progression by 67 percent, compared with 39 percent for doxazosin alone and 34 percent for finasteride alone.

Many symptoms of BPH stem from obstruction of the urethra and gradual loss of bladder function, which results in incomplete emptying of the bladder. The symptoms of BPH vary, but the most common ones involve changes or problems with urination, such as

* a hesitant, interrupted, weak stream
* urgency and leaking or dribbling
* more frequent urination, especially at night

The size of the prostate does not always determine how severe the obstruction or the symptoms will be. Some men with greatly enlarged glands have little obstruction and few symptoms while others, whose glands are less enlarged, have more blockage and greater problems.

Sometimes a man may not know he has any obstruction until he suddenly finds himself unable to urinate at all. This condition, called acute urinary retention, may be triggered by taking over-the-counter cold or allergy medicines. Such medicines contain a decongestant drug, known as a sympathomimetic. A potential side effect of this drug may prevent the bladder opening from relaxing and allowing urine to empty. When partial obstruction is present, urinary retention also can be brought on by alcohol, cold temperatures, or a long period of immobility.

It is important to tell your doctor about urinary problems such as those described above. In eight out of 10 cases, these symptoms suggest BPH, but they also can signal other, more serious conditions that require prompt treatment. These conditions, including prostate cancer, can be ruled out only by a doctor’s examination.

Severe BPH can cause serious problems over time. Urine retention and strain on the bladder can lead to urinary tract infections, bladder or kidney damage, bladder stones, and incontinence—the inability to control urination. If the bladder is permanently damaged, treatment for BPH may be ineffective. When BPH is found in its earlier stages, there is a lower risk of developing such complications.