Human hair grows in a continuous cyclic pattern of growth and rest known as the " hair growth cycle." Three phases of the cycle exist: Anagen= growth phase; Catagen= degradation phase; Telogen= resting phase. This cycle applies to all hairs in the body, though their duration may vary in different areas of the body. This means that a few hairs often
Periods of growth (anagen) between two and eight years are followed by a brief period, two to four weeks, in which the follicle is almost totally degraded (catagen). The resting phase (telogen) then begins and lasts two to four months. Shedding of the hair occurs only after the next growth cycle (anagen) begins and a new hair shaft begins to emerge. On average 50-100 telogen hairs are shed every day. This is normal hair loss and accounts for the hair loss seen every day in the shower and with hair combing. These hairs will regrow. At any given moment, about 90 percent of these follicles are in the anagen, or growing phase and not more than 10 percent of the follicles are in the resting phase (telogen) at any time. The prolonged growth phase and the high percentage of hairs in growth phase are responsible for the long hairs on the scalp.
During this phase, which lasts between two and six years depending on genetic factors and age, hair grows approximately a half-inch each month This cycle is controlled by a number of factors such as hormonal and nutritional factors, stress etc.
Of these, androgens (male hormones-testosterone, dihydrotestosterone) are the most important control factors of human hair growth, both in men and women. Androgens must be present for the growth of beard, axillary (underarm), and pubic hair. The growth of scalp hair is NOT androgen-dependent but androgens are responsible for the development of male and female pattern hair loss.
Improper Hair Cosmetic Use/Improper Hair Care - Various chemical treatments on the hair, including dyes, tints, bleaches, straighteners and permanent waves may cause the hair to 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. If hair becomes brittle from chemical treatments, it's best to stop until the hair has grown out.
Hairstyles that pull on the hair, like ponytails and braids, should not be pulled tightly and should be alternated with looser hairstyles. The constant pull causes some hair loss, especially along the sides of the scalp.
Frequent Shampooing, combing and brushing too often, using a hot air dryer can also damage hair, causing it to break. Using a cream rinse or conditioner after shampooing will make it easier to comb and more manageable. When hair is wet, it is more fragile, so vigorous rubbing with a towel, and rough combing and brushing should be avoided. Use wide toothed combs and brushes with smooth tips.
Many conditions, diseases, and improper hair care result in excessive hair loss. People who notice their hair shedding in large amounts after combing or brushing, or whose hair becomes thinner or falls out, should consult a dermatologist. With the correct diagnosis, many people with hair loss can be helped.
At our clinic, we evaluate a patient's hair problem by asking questions about diet, medications including vitamins and health food is taken in the last six months, family history of hair loss, recent illness and hair care habits. Hormonal effects may be evaluated in women by asking about menstrual cycles, pregnancies and menopause. After examining the scalp and hair, we also may check a few hairs under the microscope. Sometimes blood tests or a scalp biopsy may be required for an accurate diagnosis. It's important to find the cause and whether or not the problem will respond to medical treatment.
Other investigations that may be performed include trichoscan and trichogram. Trichoscan is done to assess the density, type of units, assess the number of miniature hairs and assess response to treatment. A trichoscan or hair scan is a simple test to detect miniaturization, and thereby estimate whether there likely possibility of permanent baldness. It takes only 10 minutes to perform and costs only Rs 500.
Emotional turmoil, medications, skin conditions, surgery, childbirth, poor nutrition and illnesses can cause hair follicles to enter the telogen phase prematurely, resulting in increased shedding which presents itself as temporary diffuse thinning.
Among the many medical conditions that can cause hair loss, the most common ones are:
• Anemia • Thyroid disease
• Other endocrine problems (especially those that produce excess androgens)
• Gynecological conditions - such as ovarian tumors • Connective tissue disease (such as Lupus)
• Surgical procedures and general anesthesia
• Rapid weight loss or crash diets that are not nutritionally balanced
• Severe emotional stress
• Drugs such as oral contraceptives, thyroid medication, blood pressure medication (such as beta-blockers or water pills),"mood" medication such as lithium, Prozac, or tri-cyclic antidepressants, blood thinners such as heparin or coumadin,cholesterol lowering medication
The treatment of all these medical causes of hair loss (which never cause total baldness) is that of the underlying cause. Proper nutrition containing proteins, vitamins and minerals, avoiding stress and treatment of the underlying disease, by a specialist, is advised.
Localized hair loss may be sub-divided into scarring and non-scarring types. Alopecia Areata is a genetic, auto-immune disease that typifies the non-scarring type. It manifests itself with the sudden onset of round patches of hair loss associated with normal skin and can be treated with local injections of Cortico-steroids. Fungal infections can cause hair loss in children. Scarring Alopecia can be caused by a variety of medical or dermatological conditions such as Lupus and Lichen Planus, or local radiation therapy. Baldness from injuries, or from local medical problems that have been cured, is usually amenable to hair transplantation. Traction Alopecia is the hair loss that occurs with constant tugging on the hair, in some beauty treatments.
Contrary to popular belief, dandruff usually does not cause hair loss. Likewise, type of water, frequent shampooing, oiling the scalp does not affect hair growth at all. Various shampoos which claim to make the hair grow have no basis.