Hair loss Causes

By far, the most common cause of hair loss, androgenetic alopecia (AGA), is due to a confluence of genetic, hormonal and age-related changes.

Nine year old children do not typically lose hair due to these factors. While scalp hair grows individually --- and may grow for three to five years --- the course of each growing cycle varies by anatomical location and also by individual. In general, the growth phase of scalp hair, known as anagen, typically lasts for several years. During this time, scalp hair grows about 1/2 inch a month. Upon reaching the end of its growing cycle the hair transitions into a resting phase called telogen.

At the end of the telogen phase, the vestigial hair shaft falls out and a new one begins to grow in its place. Once a hair is shed, the growth process begins anew. Most people normally shed 50 to 100 hairs a day. But with about 100,000 hairs in the scalp, this amount of hair loss shouldn't cause noticeable thinning of the scalp hair. In fact, most people will not notice hair loss until they've shed approximately 50% of the hairs on their scalp! And while gradual thinning is considered a normal part of aging, the situation is harder to accept in younger individuals, particularly when the hair loss is sudden or profound. Here, we'll explore some of the more common forms that hair loss may take. Before seeking treatment for a hair loss condition, we strongly encourage you to visit with your primary care provider. He or she is in the best position to offer sensible medical advice.

Specific Causes Of Hair Loss

Pattern baldness (androgenetic alopecia). In male and/or female-pattern hair loss, the duration of (anagen) growth shortens, and each cycle of replacement hairs are not as thick or robust. With each growth cycle, the hairs become rooted more superficially and more susceptible to fall out or breakage.

As previously stated, genetics plays a key role. A history of pattern hair loss on either side of your family increases your risk of balding, and hair loss-affected first degree relatives on both sides dramatically ups the ante. Your genetic identity also determines the age at which you may begin to lose hair and also the speed, pattern and extent of your hair loss.

Cicatricial (scarring) alopecia.

This far less common type of permanent hair loss occurs when inflammation damages and scars the proliferative organ structures within the viable hair follicle. This scarring essentially prevents new hair from growing

Cicatricial alopecia can be observed in several skin conditions, including lupus erythematosus, folliculitis keloidosis, or lichen planus. Though work continues to study the disorder, the underlying dynamics have not yet been fully worked out.

Alopecia areata

Alopecia areata is classified as an autoimmune disease, and new research suggests a linkage to other autoimmune diseases, including, perhaps, celiac disease. People who develop alopecia areata are generally in good health. A few people may have other autoimmune disorders, including thyroidopathy.

Some believe that certain individuals are genetically predisposed to develop alopecia areata and that a trigger, such as a virus or other environmental factor, sets the wheels in motion. A family history of alopecia areata renders one significantly more likely to develop the disease. With alopecia areata, hair may grow back in the lesion, but the problem may return, worsen (alopecia totalis), or even lead to complete loss of all hairs on the head and body (alopecia universalis).

Telogen effluvium

This type of hair loss is usually due to a change in your normal hair cycle. It may occur when some type of shock to your system — emotional or physical — causes hair roots to be pushed prematurely into the resting state. The affected growing hairs from these hair roots fall out. In a month or two, the hair follicles become active again and new hair starts to grow.

Telogen effluvium may follow emotional distress, such as a death in the family or a physiological stress, such as a high fever, sudden or excessive weight loss, extreme diets, nutritional deficiencies, surgery, or metabolic disturbances. Hair typically grows back once the condition that caused it corrects itself, but it usually take months.

Traction alopecia

Excessive hairstyling or hairstyles that pull your hair too tightly cause traction alopecia. If the pulling is stopped before there's scarring of your scalp and permanent damage to the root, hair usually grows back normally.

Other causes of hair loss Poor nutrition

In rare instances, having inadequate protein or iron in your diet or poor nourishment in other ways may cause you to experience hair loss. Fad diets, crash diets and certain illnesses, even including eating disorders, can cause poor nutrition leading to loss of hair.

Disease

Diabetes and lupus erythematosis can cause hair loss

Medical treatments

Undergoing chemotherapy or radiation therapy commonly causes one to develop alopecia. Under these conditions, healthy, growing (anagen) hairs can be affected. After your treatment ends, lost hair typically begins to regrow.

Hormonal changes

Hormonal changes and imbalances can cause temporary hair loss. This may be due to pregnancy, childbirth, discontinuation of birth control pills, the onset of menopause, or an overactive or underactive thyroid gland. The hair loss may be delayed by up to three months following a hormonal change, and it can take another three months for new hair to grow back. During pregnancy, it's normal to experience thicker, more luxuriant hair. It's also common to lose more hair than normal shortly after delivery. If a hormonal imbalance is associated with an overproduction of testosterone, there may be a thinning of hair over the crown of the scalp. Correcting hormonal imbalance with estrogen therapy may ameliorate hair loss.

Hair over-processing

Chemicals used for dying, tinting, bleaching, straightening or permanent waves can cause hair to become damaged and break off if they are overused or used incorrectly. Overstyling and excessive brushing may cause hair to fall out, particularly if the hair shaft becomes damaged.

Scalp infection

Infections, such as ringworm, can invade the scalp, ultimately leading to hair loss if not treated. Once infections are treated, lost hair generally grows back. Ringworm, a fungal infection, can usually be treated with a topical or oral antifungal medication.

Trichotillomania (hair-pulling disorder)

Trichotillomania is a type of thought disorder in which people have an irresistible urge to pull on their hair, whether it's from the scalp, their eyebrows or other areas of the body. Hair pulling from the scalp eventually renders the area with patchy bald spots, which may become highly visible over time. Causes of trichotillomania are still being researched, and no specific cause has yet been found, but antidepressant medication has been used by some individuals with varying degrees of success.