Growth and Fall of Hair – The Stages, Causes, And Effects
The growth of hair is more complicated than we realize. Over several years, hair grows in four distinct stages. It will be much easier to take care of our tresses if we understand the concept of hair growth and hair loss. It is important to understand the hair growth cycle if you suffer from hair thinning, or hair loss, or have a family member who suffers from pattern baldness.
A description of the stages of hair growth:-
Every part of the body, including the hair, goes through a complex, multi-stage growth process. It is typical for a person to experience three inches of hair growth in six months and approximately six inches of hair growth in a year.
Hair follicles and hair shafts make up the hair structure. Hair follicles are located beneath the scalp’s surface and are the primary source of new hair growth. Cell division occurs in folicles, which are living structures. The hair shaft is the part of the hair that grows outside the hair scalp and is attached to the scalp with a hair bulb.
There are three established phases of hair growth:
- A follicle’s anagen or growth phase occurs when hair grows out from its bulb to its full length. At this stage, the hair shaft gets longer due to rapid cell division.In the anagen phase, hair grows about one inch every month. This phase lasts for about five to six years. This means that hair can reach a length of 30 inches if it is not cut.
- Catagen is a transitional phase characterized by a decrease in blood supply to the hair follicles. During this period, the hair stops growing. Catagen lasts for about 10 days.
- This is the resting phase when the hair follicles remain attached to the strands, but the growth stops. The telogen phase lasts about 90 to 100 days.Approximately 10 to 15% of hair strands go through the telogen phase at some point in time, resulting in the loss of 50-100 hair strands per day.
- There is also a 4th phase in the hair growth cycle known as the exogen phase, during which hair strands fall from the roots and a whole new process begins. The exogen phase lasts about two to five months.
Each strand of hair grows independently at a different rate, otherwise, all of the hair would grow and fall out at once. In addition to metabolic imbalances, illnesses, improper nutrition, stress, and chemicals, the disruption of the hair growth cycle is another cause of hair loss.
What is hair loss?
In contrast to normal hair fall, hair loss indicates that the hair growth cycle has been disrupted. While hair fall marks a few hair strands lost each day, hair loss leads to a decrease in volume and density. There are many causes behind hair loss; some of them are reversible and some irreversible.
Types of hair loss:-
- Androgenetic Alopecia:- The most common type of hair loss is androgenetic alopecia, which affects more than 50 million men and 30 million women in the United States. Androgenetic alopecia can be treated with medication, but it is hereditary.
Male Pattern Hair Loss:-
As men age, their hair loss can begin above the temples and progress around the perimeter and top of the head, often leaving a ring of hair at the bottom.. Many men with male pattern hair loss eventually become bald.
Female Pattern Hair Loss:-
A woman’s hair slowly thins all over her scalp, but the hairline usually does not recede as a natural part of aging. Most women experience this type of hair loss after puberty, but hair loss can begin at any age. Female pattern hair loss can cause hair to thin dramatically, but only rarely does it lead to baldness.
- Telogen Effluvium:- Telogen effluvium usually begins three months after a medical event. If the triggering event is temporary—for example, if you recover from an illness or stop taking the medication causing the hair loss—your hair may grow back after six months. Telogen effluvium is considered chronic if hair loss lasts longer than six months. For reasons that are unclear to doctors, this type of hair loss may last for years in some people. If hair doesn’t regrow on its own, our dermatologists can offer medication that can help.
- Anagen Effluvium:- Anagen effluvium is rapid hair loss resulting from medical treatment, such as chemotherapy. These potent and fast-acting medications kill cancer cells, but they may also shut down hair follicle production in the scalp and other parts of the body. After chemotherapy ends, hair usually grows back on its own. Dermatologists can offer medication to help hair grow back more quickly.
- Alopecia Areata:- Alopecia areata is an autoimmune condition, which means the body’s immune system attacks healthy tissues, including the hair follicles. This causes hair to fall out and prevents new hair from growing. This condition can affect adults and children, and hair loss can begin suddenly and without warning. Hair from the scalp typically falls out in small patches and is not painful. Hair in other parts of the body, including the eyebrows and eyelashes, may also fall out. Over time, this disease may lead to alopecia totalis or complete hair loss. Dermatologists treat alopecia areata with medication that may help hair regrow. If you are interested in talking with other people who have alopecia areata, NYU Langone hosts a monthly support group for people with this condition.
- Scarring alopecia: Health conditions such as the formation of lupus and lichen planus, or even acne, cellulitis, and folliculitis lead to this type of hair loss. Hot combs and tight ponytails as well as braids also lead to this problem. This is a permanent form of hair loss and cannot be reversed.