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 (small circular or coin size patches of scalp baldness that usually grow back within months),
  • traction alopecia (thinning from tight braids or ponytails),
  • trichotillomania (the habit of twisting or pulling hair out),
  • tinea capitis (fungal infection). 

What is 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 regrows in white where it was previously dark. In another variant, alopecia can produce two or three bald patches. When these regrow, others may replace them. 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 or eyebrows.

Alopecia areata is an autoimmune condition in which the body attacks its own hair follicles. Most alopecia patients, however, do not have systemic problems and need no medical tests. While alopecia areata is frequently blamed on “stress,” in fact, it may be the other way around; that is, having alopecia may cause stress.

Treatments for alopecia areata include injecting small amounts of steroids like triamcinolone into affected patches to stimulate hair growth. Although localized injections may not be practical for large areas, often this is a very effective treatment in helping the hairs return sooner. Other treatments such as oral steroids, immune suppressives, or ultraviolet light therapy are available for more widespread or severe cases but may be impractical for most patients because of potential side effects or risks. In most mild cases, patients can easily cover up or 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.

Medically Reviewed by a Doctor on 2/27/2014

What is traction alopecia?
This is a small or localized hair loss area caused by repetitive or persistent pulling or force on hair roots. 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 tension on hair. The sooner this is done the better to avoid permanent damage.

What is trichotillomania?
This refers to the habit of someone voluntarily pulling at their own hairs or twisting them, sometimes without realizing it. The scalp and eyelashes are often affected. Unlike alopecia areata patches, which are perfectly smooth, hair patches in trichotillomania show broken-off hairs. Treatment is often entirely behavioral: You have to notice that you’re doing it and then consciously stop. Severe or resistant cases may require stress counseling with a therapist or psychologist or medical treatment with a psychiatrist. Several anti depressant or anxiety medications have been shown to help with this condition.

What is tinea capitis?
Tinea is the medical word for fungal infection, and capitis means head. Tinea capitis is fungal infection of the scalp that for the most part affects school-age children. Tinea capitis is more common in black African or African-American scalps. This condition is rare in healthy adults. Bald spots usually show broken-off hairs and is accompanied by a dermatitis. Oral antifungals can penetrate the hair roots and cure the infection, after which hair grows back. Sharing hats or combs and brushes may transmit tinea capitis.

What is generalized (diffuse) hair loss?
This is an overall hair thinning without specific bald spots or patterns. While this type of hair loss may not be noticeable to others, often the individual will feel their hair is not as thick or full as it previously was. Common conditions in this category are

  • telogen effluvium (rapid shedding after childbirth, fever, or suddenweight loss);
  • androgenetic or androgenic hair loss (“male-pattern baldness,” “female-pattern baldness”).

 

 What is telogen effluvium?
Under normal conditions, scalp hairs live for about three years (the anagen, or growing, phase); they then enter the telogen, or resting, phase. During the three-month telogen 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 who worry 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,
  • severe illness,
  • severe emotional stress or loss.

None of these need be life-threatening, nor does hair loss usually follow them. (Moreover, 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; these people need no special treatment. Normal shampooing can continue, because this only loosens hairs that were going to come out anyway.

 

What is androgenetic or androgenic alopecia (“male-pattern baldness,” “female-pattern baldness”)?
This type of alopecia is often attributed to genetic predisposition and family history. Androgenic alopecia is seen in both men and women. The hair loss in men is often faster, earlier onset, and more extensive.

Doctors refer to common baldness as “androgenetic alopecia” or “androgenic alopecia,” which implies that a combination of hormones and heredity (genetics) is needed to develop the condition. The exact cause of this pattern is unknown. (The male hormones involved are present in both men and women.)

Male-pattern baldness
Even men who never “go bald” thin out somewhat 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

  • People inherit baldness through their mother’s male relatives. Actually, baldness can come from either side of the family or both. Looking at one’s family can give someone at best an educated guess about how he or she will turn out. Studies are ongoing in this field, and current research has been inconclusive about the inheritance patterns.
  • Longer hair puts a strain on roots. It doesn’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.

Is hair loss in women different than men?
Female-pattern baldness
     Women lose hair on an inherited (genetic) basis, too, but the female pattern tends to be more diffuse, with less likelihood of the crown and 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. There seems to be a normal physiologic thinning that comes with age and occurs in many women in their early to mid 30s. More women have underlying causes of hair loss than men. These include treatable conditions like anemia and thyroid disease and polycystic ovary syndrome. These conditions are diagnosed by blood tests along with a historical and physical evidence. Although a few studies have suggested that baldness may be inherited through the mother’s family genes, these theories require further testing. Current studies are inconclusive.

While stories about hats choking off follicles or long hair pulling on the roots may be more folklore, repeat hair trauma like tightly woven hair pulled back and consistent friction can potentially worsen or cause localized hair loss in some individuals. Individuals who pull their hair tightly back in a rubber band can develop a localized hair loss at the front of the scalp.

Hair loss “myths” of special concern to women

  • Longer hair does not necessarily 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. Burns or severe processing may cause hair loss and breakage. Styles that pull tight may cause some loss, but hair coloring and “chemicals” usually don’t.

Medically Reviewed by a Doctor on 2/27/2014

Source(s): http://www.medicinenet.com/hair_loss/