Hair loss (alopecia) Types and Causes

Hi friends today I would like to say about Hair Loss. Before going to that I am giving brief information on Hair.

Hair is made up of keratin (protein) which is produced in hair follicles on the outer layer of skin. These Follicles are responsible for production of new hair cells. Generally hair is a thread of dead keratin cells. The average adult head has about 100,000 to 150,000 hairs and loses up to 100 of them a day.

At any point of time, about 90% of the hair on a person's scalp is growing. Each follicle has its own life cycle that can be influenced by age, disease, and a wide variety of other factors. The life cycle of Hair is divided into three phases,

1)      Anagen Phase:

The anagen phase is the “growing” phase of a hair follicle. In this phase hair follicle starts to grow back to full size and extend deeper into the skin. Scalp hairs grow about one-half inch per month during the anagen phase.

The period of time typically ranging from four to six years. This is a rapid rate of cellular growth compared to most other tissues in the body.

2)      Catagen Phase:

In this phase Hair stops growing and the hair follicle starts shrinking. This “regression” period is called the catagen phase. The catagen phase for scalp hair follicles lasts about two to three weeks.

3)      Telogen Phase or Resting Phase:

During this phase the follicle appears inactive and the hair shaft may also be shed during this period. Shed hairs may appear on bedding, on clothing, in combs and brushes.Many shed hairs simply go down the drain after shampooing. The time period of this phase is Three months.

What is Hair Loss?

Hair loss also known as alopecia or baldness, It means loss of hair from the head or body. Baldness can refer to general hair loss or male pattern hair loss.

There are many types of hair loss

• Involutional alopecia:

It is a natural condition in which the hair gradually thins with age. More hair follicles go into the resting phase, and the remaining hairs become shorter and less in number.

• Androgenic alopecia:

It is a genetic condition that can affect both men and women. Men with this condition, called male pattern baldness, can begin suffering hair loss as early as their teens or early 20s. It is characterized by a receding hairline and gradual disappearance of hair from the crown and frontal scalp. Women with this condition, called female pattern baldness, don't experience noticeable thinning until their 40s or later. Women experience a general thinning over the entire scalp, with the most extensive hair loss at the crown.

• Alopecia areata:

It starts suddenly and causes patchy hair loss in children and young adults. This condition may result in complete baldness (alopecia totalis). But in about 90% of people with the condition, the hair returns within a few years.

• Alopecia universalis:

It causes all body hair to fall out, including the eyebrows, eyelashes, and pubic hair.

• Trichotillomania:

This Problem seen most frequently in children, is a psychological disorder in which a person pulls out one's own hair.

• Telogen effluvium:

It is temporary hair thinning over the scalp that occurs because of changes in the growth cycle of hair. A large number of hairs enter the resting phase at the same time, causing hair shedding and subsequent thinning.

• Scarring alopecias (Cicatricial Alopecias):

It results in permanent loss of hair. Inflammatory skin conditions (cellulitis, acne) and other skin disorders (such as some forms of lupus and lichen planus) often result in scars that destroy the ability of the hair to regenerate. Hot combs and hair too tightly woven and pulled can also result in permanent hair loss.

What Causes of Hair Loss?

There are different factors may influence hair loss,

• Genetics: Almost all pattern hair loss is caused by heredity, from genes passed on by both maternal and paternal ancestors.

• Hormones, such as abnormal levels of androgens (male hormones normally produced by both men and women)

• Autoimmune disorders may cause patchy hair loss in children and young adults.
• Diseases: Thyroid disease, lupus, diabetes, Iron deficiency, eating disorders and anemia can cause hair loss.

• Nutritional deficiencies: Low protein diet or severely calorie-restricted diet can also cause temporary hair loss.
• Poisons
• Drugs including chemotherapy drugs used in Cancer treatment, Beta adrenergic blockers used to control blood pressure, and birth control pills can cause temporary hair loss.

• Radiation exposure: Ionizing radiation such as the type used for cancer treatment, also affects rapidly dividing cells most severely, and, as a result of exposure to radiation, actively producing hair follicles are shut down.

• Stress, illness and childbirth can cause temporary hair loss.
• Physical trauma to the scalp such as from wounds from accidental cutting or impact, thermal burns from heat or fire, chemical burns from acids, alkalis, or other caustic substances.

• Hair styling technique: This type of hair loss called traction alopecia can result from certain hair-styling techniques that pull tightly on the hairs, such as tight “cornrow” braids and pigtails. Modifying these styling techniques so that they are not too tight solves the problem.

• Cosmetic products and procedures that weaken or damage the hair shaft can result in hair loss.
• Common causes: There have been numerous causes blamed for pattern hair loss, including “hot blood,” excessive blood circulation in the scalp, inadequate blood circulation in the scalp, wearing hats, brushing the hair too much, brushing too little, dirty scalps, oily scalps, hormones in scalp oil, dandruff, various diseases, excessively tight scalps, inadequate oxygen reaching the hair follicles, inadequate nutrition or nutritional deficiencies, “sleeping” hair follicles, and hairs “stuck” in the hair follicles.