It is normal to lose between 50-100 hairs a day, this is part of the hair renewal process. However most people suffer from excessive hair loss at one time in their life. There are many reasons for this including medication, radiation, chemotherapy, exposure to chemicals, hormonal and nutritional factors, thyroid disease, generalized or local skin disease, and stress.
Many of these causes are temporary and a few are permanent. These are some of the more common reason for hair loss.
Since hormones both stimulate hair growth and cause hair loss, hormonal changes by far have the biggest impact on hair loss. These can affect both men and women in the following ways:
This is the most common cause of thinning and affects both men and women. Men generally have hair loss concentrated in a specific pattern from the front through to the crown. Women tend to have thinning throughout their head without being in any specific pattern. This type of hair loss is caused by the androgen DHT, or Dihydrotestosterone. Since everyone has DHT that is produced by their bodies and only some people suffer from hair loss there has to be another factor involved. This other factor is having follicles that have a greater number of Androgen receptors for the DHT to attach to. This is the component that is inherited through the genes. To date the most effective preventative treatments are anti androgens, drugs that prevent the creation of DHT. In the future gene therapy will one day be able to alter the genes to prevent the follicles from being affected by DHT.
After pregnancy many women experience a loss of hair, this is caused many hair simultaneously entering the resting (telogen) phase. Within two to three months after giving birth, some women will notice large amounts of hair coming out in their brushes and combs. This can last one to six months, but resolves completely in most cases. This condition is caused by the hormonal changes that take place after a woman's body recovers from her pregnancy.
Birth control pills
Women who have a genetic predisposition to suffer from Androgenic Alopecia can have it occur at a much younger age by taking birth control pills. The hormonal changes that occur trigger the onset of the Androgenic Alopecia. If a woman has a history of female pattern loss in her family she should advise her doctor before going on the pill. After the discontinuation of the pill the woman may notice that her hair begins shedding two or three months later. This may continue for six months when it usually stops. In some cases the process cannot be reversed and the woman may not regrow some of the hair that was lost.
DISEASE OR ILLNESS INFLUENCES
Since the follicle is a very sensitive it does respond to imbalances in the body. Most hair loss causes by disease or illness is temporary and resolves itself after the body has returned to a healthy condition.
High fever, severe infection, severe flu
Sometimes one to three months after a high fever, severe infection or flu, a person may experience hair loss, this is usually temporary and corrects itself.
Both an overactive thyroid and an underactive thyroid can cause hair loss. Thyroid disease can be diagnosed by your physician with laboratory tests. Hair loss associated with thyroid disease can be reversed with proper treatment.
Some people who go on low protein diets, or have severely abnormal eating habits, may develop protein malnutrition. To help save protein the body shifts growing hair into the resting phase. If this happens massive amounts of hair shedding can occur two to three months later. A sign of this is if the hair can be pulled out by the roots fairly easily. This condition can be reversed and prevented by eating the proper amount of protein. Its very important when dieting to maintain an adequate protein intake.
Some prescription drugs may cause temporary hair shedding in a small percentage of people. Examples of such drugs include some of the medicines used for the following: gout, arthritis, depression, heart problems, high blood pressure, or blood thinner. High doses of vitamin A may also cause hair shedding.
Chemotherapy and radiation treatment will cause hair loss because it stops hair cells from dividing. Hairs become thin and break off as they exit the scalp. This occurs one to three weeks after the treatment. Patients can lose up to 90 percent of their scalp hair. The hair will regrow after treatment ends and patients may want to get wigs before treatment. There are some drugs in development to help prevent this hair loss from occurring.
Low serum iron
Iron deficiency occasionally produces hair loss. Some people don't have enough iron in their diets or may not fully absorb iron in their diets. Women who have heavy menstrual periods may develop iron deficiency. Low iron can be detected by laboratory tests and can be corrected by taking iron pills.
Major surgery/chronic illness
Anyone who has a major operation - a tremendous shock to the system - may notice increased hair shedding within one to three months afterwards. The condition reverses itself within a few months but people who have a severe chronic illness may shed hair indefinitely. A relatively unknown fact is that hair transplantation surgery can actually cause additional hair loss or "shock fallout". Hairs lost from shock fallout usually don't regrow.
This type of hair loss is believed to be caused by the immune system reacting to hair follicles as if they were antibodies and shutting them down. The hair loss is usually limited to a coin sized area and all the hair in the area is lost leaving a totally smooth round patch. In a more severe rarer condition called Alopecia Totalis, all hair on the entire body is lost, including the eyelashes. Treatments include topical medications, a special kind of light treatment, or in some cases drugs.
Fungus Infection (Ringworm) of the scalp
Caused by a fungus infection, ringworm (which has nothing to do with worms) begins with small patches of scaling that can spread and result in broken hair, redness, swelling, and even oozing. This contagious disease is most common in children and oral medication will cure it.
n cause hair loss is some people. Usually it occurs 3 months after the stressful event has occurred and it may take 3 months after the stress period has ended for the hair growth to resume. In most cases it is temporary if the person is not predisposed to genetic or Androgenic Alopecia, if they are stress may trigger the onset of genetic hair loss or may worsen existing Androgenic hair loss.
MECHANICAL DAMAGE CAUSES HAIR LOSS
Damage to the hair can be self inflicted either by intentional or unintentional means. Some people going through stress continuously pull at their hair until it comes out. Styling hair by bleaching, braiding and straightening can also cause damage and results in hair being lost.
Trichotillomania or Hair Pulling
Some children and less often adults play with their hair by pulling on it or twisting it. This can be part of a behavioral problem or a bad habit that is often done unconsciously. If the behavior is not stopped permanent hair loss can result from the constant stress on the hair. Its best to seek the help of a mental health professional to solve this problem.
Hair Styling Treatments
Many people change the appearance of their hair by using chemical treatments like dyes, tints, bleaches, straighteners, relaxers and permanent waves. If correctly done and done using reputable products, its rare to have any damage. However, hair can become weak and break if any of these chemicals are used too often. Hair can also break if the solution is left on too long, if two procedures are done on the same day, or if bleach is applied to previously bleached hair. Some chemical relaxers do contain powerful chemicals and there have been instances of people get chemical burns from these products resulting in permanent hair loss. Only go to qualified hair stylists and if doing it yourself make sure you only use reputable products and follow the product directions.